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SERIAL NO

REPLACEMENT PARTS - see MAINTENANCE Parts Ordering

Changes special to this unit ___

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MOD E L 217 2

SELECTIVE VOLT~mTER

INDEX

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SPECIFICATIONS

MODEL FREQUENCY

RANGE SELECTIVITY LEVEL

FULL SCALE ACCURACY TYPICAL FILTER

SELECTIVITY

I 2171A

60 Cycles to 30 Cycle or -68 to +32dbm -+- 5db -80 I 6 Kilocycles 50 Cycle Filter to +32dbm

300 Cycles to 4 Kilocycles

300 Cycles to 50 Cycle or -68 to +32dbm -+- 5db -80 to2174A 400 Kilocycles 100 Cycle Filter +32 dbm 300

to 400 Kilocycles SPURIOUS RESPONSE Below 60db LOW INTERMODULATlON Below 60db POWER REQUIREMENTS 115 V AC-5060 Cycles WEIGHT 28 Ibs

Including a wider filter and demodulator for monitoring SSB AM and FM signals

30 CYCLE FILTER 6db- 35 Cycles

60db-250 Cycles

50 CYCLE FILTER 6db- 60 Cycles

60db-450 Cycles 100 CYCLE FILTER 6db-140 Cycles

60db-900 Cycles

I I

A highly selective measuring instrument utilizing the heteroshydyne principle with balanced modulation offers fast and accurate means of making amplitude measurements High resolution is achieved by means of highly selective crystal It~~2~reg filters with a 50 or 100 cycle filter available for amplitude

A Division ofmeasurements A 3 kilocycle filter with demodulator is proshy RAILWAY COMMUNICATIONS INC vided for monitoring of SSB speech or tone signals 9351 East 59th Street Raytown Missouri

MODEL 2174A FUNCTIONAL BLOCK DESIGN

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ltBandwidth 50 CYCLE FILTER

6db - 60 Cycles 60db - 450 Cycles 100 CYCLE FILTER Submit your requirements for special deviations from above instruments 6db - 140 Cycles

60d b - 900 Cycles 3KC FILTER

3db - 2140 Cycles 45db - 4200 Cycles 10KC FILTER

3d b - 4460 Cycles 45db - 24950 Cycles

Average Measure

A Division of

RAILWAY COMMUNICATIONS INC 9351 E59TH STREET RAYTOWN MISSOURI

Phone Code 816-FLeming 3-2100

Printed in U S A

INSPECTION

This instrument has been thoroughly tested and inspected before shipment

The instrument should be inspected for damage as soon as it is received If no damage is apparent test for operation according to operating instrucshytions in this manual

SU~~Y

The Selective Voltmeter is a highly selective instrument for m~king voltage measurements of frequencies from 3 to 160 kc varying in level from -90 to +32 dbm (30 volts maximum without external attenuator) Zero dbm reference is 1 milliwatt of power (or 775 volts) in a 600Q load The input signalis attenuated to the proper value by the attenuator amplified and demodushylated to 500 kc by a shunt type demodulator and variable oscillator This 500 kc signal passes through a sharp crystal filter then is amplified and detected The dc output is applied to a 200 microampere meter The meter has dbm and voltage scales and is calibrated to indicate the signal level at the instruments input connector

A wide crystal filter or broad tuning may be selected for monitoring~ In this use the SOO kc amplifier output is demodulated by a shunt type demodushylator and crystal oscillator for upper or lower sidebands by a conventional diode detector for ~I signals or by slope detection of FM signals The monitor output is to a speaker or headset jack An internal calibratingcircuit is provided so calibration can be made or checked as desired

DESCRIPTION

GENERAL

All symbols referred to such as (Vl) (X9) (RS3) or capitalized such as CAL 1 LEV or METER are stamped on the chassis or front panel of the instrument andor used in the schematic drawing

The input circuit contains a condenser (Cl) to block DC potentials a transshyformer in the input of 3002 filter so that measurements can be made on balshyanced circuits a 400 kilocycle lowpass filter (3002) and an attenuator The input impedance and balance or unbalance is controlled by UNBAL-BAL switch (Sl) The ATTENUATOR properly adjusts the input signal applied to Vl and has a CAL position used in calibrating the instrument The isolashytion amplifier (Vl) feeds a shunt type balanced demodulator (V2) whose balshyance is controlled by MOD BAL controls C amp R A variable frequency LC osshycillator ( V3) and phase inverter ( V3) supplies carrier frequency for demodulation This frequency is controlled by the main tuning condenser (C36) BAND SEL switch (S3) and a trimmer condenser (e83) CAL 2 TRIM The 50 cps or 3 kc crystal filter (Xl through X4 amp Tl or XS through X8 amp T2) or 10 kc broad coupling (C26 and 29) passes the lower sideband of demodulashytion The SOO kc IF amplifier (V4amp VS) feeds both the measure (~6~ D3-4~ and monitor (V8 9 amp 10) sections of the instrument The IF amp11f1er ga1n is adjusted by CAL 2 LEV (R37) The meter circuit amplifier (Vo) feeds a series shunt type meter rectifier (D3 amp D4) whose output indicates on a 200 microampere meter calibrated in dbm and volts

1

The amplifier (V8) feeds a series type demodulator (Dl D2) for monitoringlower sideband (LSB) or upper sideband (USB) signals The carrier for this demodulator is supplied by a crystal controlled oscillator ( V9) For monshyitoring amplitude modulated signals or slope detection of FM signals this oscillator is made inoperative and diode D2 removed thus the circuit opershyates as a conventional diode detector The resulting audio signal passes through the RC filter (R40 C57 C58) and amplifier ( V9 VIa) to the speaker or a headset plugged into the HEADSET jack (J3) The audio output amplitude is controlled by the potentiometer ~10N LEV (R42)

An audio signal may be amplified by inserting it in the AUDIO IN jack (if provided) just ahead of the audio amplifier ( V9 amp VIO)

A self contained calibration oscillator ( V7) is coupled to a cathode folshylower (A V7) whose output is adjusted by the potentiometer CAL 1 LEV (R55)

Plate power is furnished by a bridge type full wave selenium rectifier (SRI) A voltage regulator tube (Vll) stabilizes the plate supply to all cir shycuits except the monitor section

To prevent heater to cathode leakage and to lower 60 cps modulation (particshyularly in VI amp V2) the filaments are 50 volts DC above ground (R5-8 C9-10) 60 c~s modulation is further reduced by operating VI filament from a DC supshyply (C99middot- 101 SR5 SR6 R72)

INPUT

An input impedance of 135Q 600Q or bridging may be selected by the UNBALshyBAL switch (Sl) This switch also changes the input circuit from unbalanced to balanced on any impedance The BRIDGE input impedance is approxima~elyen 10000 ohms from 1 to 30 kc gradually falling to approximately 8000 ohms at 160 kc

An input impedance of 150 ohms instead of 135 ohms may be obtained by reshymoving resistor R3

Frequencies to be measured are connected to the INPUT connector (Jl) Both sides of the connector are insulated from the front panel thus isolating it from chassis ground during balanced measurements

ATTENUATOR

The attenuator provides 0 to 100 db of attenuation for measuring signals between -68 and +32 dbm (full scale meter indication)

The CAL position is connected to the voltage divider of the calibrate oscil shylator output for calibrating the isolation and IF amplifiers

LOCAL OSCILLATOR (3019)

The local oscillator (3019) is a hartley type using i of tube V3 The tank circuit consists of coil L3 and capacitors C36 C40 through C49C83C84 C88 amp C9l through C95 Capacitor C36 is the main tuning capacitor The even numbered capacitors C40 through C48 amp C88 are the trimmer capacitors

2

for calibrating each band Coil L3 and capacitor C92 are used to set freqshyuency tracking Capacitor C83 (CAL TRn~) is a front panel control affectshying all bands and is used for frequency calibration utilizing the self-conshytained calibrate oscillator as a standard

The local oscillator is varied from 5003 to 660 kilocycles by BAND SEL s~itch and the main tuning cap to measure frequencies of 3 to 160 kiloshycycles respectively as indicated on the frequency dial For example a Gignal of 1 kc is fed into the instrument The BAND SEL switch is set on i~ and frequency dial tuned to 10 kc The local oscillator is now oscillashyting at 501 kc and the lower sideband of demodulation is 500 kc which is the center frequency of the crystal filter

The oscillator half of V3 feeds the phase inverter half of V3 which provides 2pproximately equal potential (about 2 volts) to a plate and cathode of the demodulator tube V2 Potentiometers R25 (screwdriver control inside 3019 assy) and R24 (R MOD BAL on front panel) and capacitors C81 (screwdriver triwner inside 3019 assy) and C80 (C MOD BAL on front panel) adjusts the resistive and capacitive components in the demodulator circuit to give a minimum of oscillator potential at the cathode-plate junction of V2 (pins 1 amp 2) Balancing of the demodulator becomes critical only when the local oscillator frequency approaches the passband of the crystal filter (ie 500 kc) vfuen the oscillator is at 500 kc and the potential at V2 pin 1 amp 2 is balanced to the equivalent of -80 db at the input terminals the meter will indicate -10 As the oscillator frequency is increased the upper side of the crystal filter helps lower the local oscillator frequency potential that reaches the meter The narrow crystal filter rejection band provides at least 80 db of attenuation thus precise balance is not necessary except for measuring low frequencies The Demodulator Balance ii paragraph of 110perating Instructions 17 gives further details

The local oscillator is calibrated by feeding a known frequency into the instrument setting the frequency dial on the correct dial calibration and adjusting the band trimmer capacitor to obtain a peak meter indication

During operationcalibration at 1000 cps can be made using front panel conshytrols only For this the self-contained calibrate oscillator frequency is fed into VI the frequency dial is set at 1 kc and the meter indication peaked using CAL 2 TRn~

CALIBRATE OSCILLATOR

The calibrate oscillator is a hartley oscillator using of tube V7 It is ~oupled to a cathode follower (~ V7) whose output is adjusted by the potenshytiometer CAL 1 LEV (R55) Plate power is supplied to the calibrate oscilshylator only when the BAND SEL switch is in the CAL position thus it operates only during calibration This oscillator supplies potential for both amplishytude and frequency calibration as given in the calibration paragraph The calibrate oscillator is approximately 970 cps and calibrates the unit at 1000 cps (10 on band A) The difference in frequency compensates for capshyacity change in the BAND SEL switch when rotated from A to CAL

3

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SELECTIVITY

The SELECTIVITY switch is used to select one of three filters at the demodshyulator output The position marked 50 - selects a sharp crystal filter for measuring The position marked 3 KC selects a filter of appropriate width for demodulating 3 or 4 kc single sideband voice channels The position marked 10 KC selects mers determine the bathe back of the book

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coupling network dwidth of this position

to the IF amplifier whose The response curves

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D1QNITOR

The control marked MONITOR is an on-off switch for the AC power to the inshystrument and the gain control of the audio amplifier of the monitor section The USB position of the MONITOR switch connects a 50147 kc crystal to the monitor oscillator for demodulating upper sideband signals The LSB posishytion connects a 48953 kc crystal to the oscillator for demodulating lower sideband signals The AM position disconnects the plate power to the oscilshylator and disconnects diode D2 thus converting the series type demodulator to a diode detector The AM position is for monitoring amplitude or freqshyuency modulated voice channels or signals

METER SilJITCH

The t~TER switch (S5) controls the input to the meter circuit (V6 D3 amp D4 and meter) The OFF position shorts the meter input terminals to prevent pinning the needle while monitoring weak signals The ON position connects the IF amplifier output to the meter circuit for measuring and for the secshyond step of calibration The CAL 1 position connects the calibrate oscilshylator output to the meter for the first step of calibration

CALIBRATION

INTERNAL CALIBRATION amplitude and frequency Internal calibration calshyibrates the frequency dial and voltage (or DB) meter indication This is done entirely with front panel controls utilizing the self-contained calshyibrate oscillator and precision voltage divider for standards Step-byshystep procedure is given in the operating instructions

Internal calibration is accomplished in two steps The first step consists of feeding the calibrate oscillator output direct to the meter stage and adjusting the oscillator output (CAL 1 LEV) to give any desired meter indishycation (usually 0) The first part of the second step calibrates the freqshyuency It consists of rotating the FREQUENCY dial pointer to 10 on the A band and adjusting the CAL 2 TRIM control for a peak meter indication This adjustment tunes the local oscillator to the correct frequency for receivshying 1000 cps The second part of the second step calibrates the gain of the amplifiers to give proper meter indication This consists of feeding the calibrate oscillator output through the precision voltage divider (R57-R60 and attenuator CAL position) isolation amp Vl~ IF amp W4-V5) to the meter stage and adjusting the IF amp gain (CAL 2 LEV) to give the same meter inshydication set in step 1 This sets the isolation and IF amplifier gain equal to the loss in the precision voltage divider

4

BASIC CALIBRATION amplitude Basic calibration adjusts the precision voltage divider (R57-R60 and attenuator CAL position) to give the correct voltage (or DB) indication on the meter using an accurate external source as a standard This adjustment is made at the factory It can be checked and readjusted (CAL 3) if necessary as given in the maintenance section

Basic calibration consists of feeding 0 dbm into the input of the instrument and adjusting CAL 2 LEV (R37) to give zero on the meter Next the calibrate oscillator output is fed directly to the meter and adjusted by CAL 1 LEV to give 0 on the meter It is then fed through the isolation amplifier (VI) IF amp (V45 to the meter stage and CAL 3 (R58) is adjusted for 0 meter indication This adjusts the loss in the voltage divider to a value equal to the gain required in the amplifiers to give a correct meter indication

FREQUENCY BAND CALIBRATION using external frequency source The coil L3 is trimmed to set the tracking of the DE amp F bands The capacitor C92 is adjusted to set the tracking of the AB amp C bands Tracking is normally set on the F and C bands Anyone frequency on each band may be calibrated by feeding a known frequency into the instrument and adjusting trimmers C88 and C48 through C40 each for the proper band The band trimmers are progresshysively added to the tank circuit thus adjustment must be made in order from the F band to the A band Details for frequency band calibration are given in the maintenance section

5

OPERATING INSTRUCTIONS

GENERAL

Operation of the Selective Voltmeter is divided into two major functions that of measuring signals as indicated by the meter and that of monitoring carrier and audio voice bands or signals

All controls signal input audio input and output jacks and power connecshytions are on the front panel of the portable instrument Input output and power connections may be on the back of the rack mounted instrument

The power required is 48 watts 50 to 400 cps 115 volts Connection is made to the instrument with the cord furnished in the receptacle (AC) The power switch is located on the MONITOR LEVEL control where the off position is inshydicated (AC OFF)

DEMODULATOR BALANCE

Balance the demodulator as follows with the input signal disconnected (for measuring frequency below 1 kc)

a Switch positions BAND SEL on A or B FREQUENCY dial near 0 SELECTIVITY on 50 shy METER on ON MONITOR LEVEL on minimum

b Adjust MOD BAL controls C and R to obtain a mlnlmum meter reading NOTE If meter reads off scale adjust FREQUENCY dial up scale for full scale meter reading adjust C and R for preliminary balshyance (minimum meter reading) Return FREQUENCY dial to zero freqshyuency (maximum meter reading) and rebalance Repeat if necessary At final balance it should be possible to tune across 0 frequency with an on scale meter reading

c If a balance cannot be obtained within the limits (see note cl) of the CampR control on the front panel adjust the coarse CampR balance controls (see note c2) Set the CampR front panel controls in mid-range and adjust CampR coarse controls until an on scale balance is obtained Complete the balance with the front panel controls

Note cl The MOD BAL CampR controls have ball planetary drives R has a 10-turn control and C has a 4-turn control The limits of rotation are indicated when the drive slips at one extreme of rotation Note c2 Remove the unit from the case and locate the main oscillator assembly (3019) under the chassis Adjust the capacitor and potentiometer controls through the holes marked CampR

The degree of balance needed is dependent on the selectivity of the crystal filter and the frequency measured

6

L

The 50 cps crystal filter is down more than 20 db at 200 cps off and 60 db at 250 cps off thus a 0 db balance will cause negligible error when measuring a 300 cps or higher tone

A quick check is to tune in the desired signal remove the input and observe the meter reading due to carrier If it is less than an estimated -25 db tlen any reading above -10 db will be affected less than 1 db NOTE Do nnt set the meter zero on 0 volts The meter zero is used for meter trackshyi~g at -10 db

At low balance a double peak or erratic meter fluctuations may be noted These do not necessarily indicate trouble if the instrument performs satshyisfactorily when measuring a tone

The tube used as VI is critical in determining the degree of balance obtainshyable principally due to heater to cathode leakage Select a 6BH6 tube or a 66616BH6 to give best balance

INTERNAL CALIBRATION

Calibrate the instrument as follows for direct reading in dbm for the cir shycuit impedances listed Calibration for all impedances are based on 0 dbm equals 1 milliwatt of power Step CAL 2b calibrates the frequency Step CAL 2c calibrates the amplitude (meter db or voltage indication) Note Amplitude calibration is not essential for frequency calibration however frequency calibration is essential for amplitude calibration

CAL 1 a Switch positions

BAND SELECTOR to CAL ATTENUATOR to CAL METER to CAL 1 b Adjust CAL 1 LEVEL to give zero on meter DB scale for a 600Q

circuit For other circuit impedances adjust CAL 1 LEVEL to the following meter indications

(1) (3)

-6 for 150Q circuit -67 db for 130Q circuit

(2) (4)

-65 db -90 db

for 135Q circuit for 75Q circuit

CAL 2 a Switch positions

BAND SELECTOR to CAL METER to ON MONITOR to AM ATTEW0ATOR to CAL SELECTIVITY to 50 -

b Adjust FREQUENCY dial pointer to 10 on A band c d

AdjustAdjust

CAL CAL

2 TRIM to peak meter (this calibrates VAR OSC 2 LEV to give zero on meter DB scale for ALL

frequenc~)

circuit impedances (this calibrates amplitude)

This completes the calibration and the instrument is ready for use When precise measurements are needed it is recormnended that a calibration reshycheck be made during the warmup period See APPENDIX A for precautions

INPUT CIRCUIT SELECTION

The input may be unbalanced or balanced for an input impedance of 135Q 600Q or bridging as selected by the UNBAL-BAL switch The input jack on a standard unit takes a 34 spaced dual banana plug Other input conshynector types are supplied when so ordered

7

FREQUENCY SELECTION

Frequency selection is made by means of the BAND SELECTOR FREQUENCY and SELECTIVITY controls The frequency to be measured is tuned in by the large center knob and position ABC etc of the BAND SELECTOR switch

SELECTIVITY

The SELECTDIITY switch selects the crystal filter bandwidth to be used The 50 cycle position is normally used for measuring and the 3 KC and 10 KC for monitoring h~ere signals are spaced wide enough or circuit noise is low enough the 3 or 10 KC positions may be used for measuring above 3 to 6 KC or 10 to 20 KC respectively For precise measurements the internal cali shybration must be for the selectivity position to be used

AMPLITUDE MEASURElVIENT

Connect the signal to be measured to the INPUT JACK (CAUTION See overshyload paragraph) a Switch positions

BAND SELECTOR to desired band SELECTIVITY to 50 shyATTENUATOR to proper level MONITOR to AM (for precise METER to ON measurements)

b Adjust FREQUENCY dial to desired frequency and for maximum meter indication

c Add meter indication and attenuator position algebraically to obtain amplitude of signal being measured

LOW FREQUENCY ffiASUREMENTS

Measurements below about 500 cps require certain precautions The demodushylator must be balanced as given in the Demodulator Balance paragraph to prevent erroneous meter indication due to carrier leak Odd harmonics of 60 cps indicate on the meter due to internal coupling in the unit thus give a beat and cause erroneous meter indication when attempting to measure 60 and 180 cps etc The input impedance below 1 KC with the UNBAL-BAL switch on the l35Q (or below 300 cps on 600Q position) increases due to the impedance ratio of Cl to R2 amp R3 If 135Q or 600Q impedance is desired at low frequencies use the BRIDGE impedance position and an external 135Q or 600Q terminating resistor

OVERLOAD

The amplifiers of this instrument overload before the meter movement is damaged on moderate overloads--however excessive or prolonged overloads should be avoided

Amplitudes of +20 dbm or higher should not be left applied to the instrushyment for longer than a minute or two since the input circuit may heat If +20 dbm or higher amplitude is to be connected continuously a suitable pad should be connected ahead of the instrument to reduce the level below +20 dbm

LOW AMPLITUDE SIGNALS IN PRESENCE OF HIGH AMPLITUDE SIGNALS

Overloading is reduced by introducing attenuation to the input signals Therefore when measuring a low level signal when high levels are also present the more accurate reading will be made when the attenuator step is selected to give a meter reading on the lower 10 db section of the meter scale vfuen measuring circuits on which amplitudes are not approximately known it is suggested that the entire spectrum be first scanned to detershyTIline the highest amplitude signals present This will indicate the lowest level signals which may be apoundcurately measured When highest to lowest ~~els exceed 45 db some inaccuracy due to overload or intermodulation may JG 3usp~cted When measuring harmonics of a single frequency input accurshyate readings may be made 50 db or less for 2nd and 60 db or less for 3rd hi~rmonics

In any case when a low level signal is being measured if the attenuator switch is changed by 10 db and the meter reading also changes 10 db the measurement can be considered accurate

vfuen many input signals are present no simple rule can be followed as the overload point is determined by the peak envelope of the combined signals which may vary with their amplitude and phase

CARRIER MONITORING

The Selective Voltmeter may be used to monitor lower sideband (LSB) upper sideband (USB) amplitude modulated (AM) or frequency modulated (FM)signals Use the 3 kc position of SELECTIVITY switch above 3 kc only and the 10 kc position above 10 kc only

1 Upper and lower sideband monitoring a Connect the input connector to the circuit to be monitored b Switch positions

SELECTIVITY to 3 KC BAND SEL switch amp FREQUENCY DIAL to midband frequency of the

sideband MONITOR switch to LSB or USB as required MONITOR LEVEL--adjust as needed

If the voice or signal from the speaker (or headset if used in HEADSET jack) is weak turn the I1ETER switch off and the ATTENUATOR down until the desired level is reached

2 AM monitoring

To monitor AM signals feed the signal in the INPUT connector turn the seshylectivity to 3 kc or 10 kc set the MONITOR switch to AM tune the FREQshyUENCY dial to the carrier frequency and adjust the amplitude as for single sideband signals

3 FM monitoring

To monitor FM signals by slope detection feed the signal in the INPUT conshynector turn the SELECTIVITY switch to 10 kc set the MONITOR switch to AM adjust the frequency dial for best reception (one side of thA selectivity curve) and adjust the aDlplitude as for single sideband signals

9

AUDIO MONITORING (on units with AUDIO IN jack)

The audio section of the monitor circuit may be used as a amplifier if desired by inserting the signal in the AUDIO

voice frequency IN jack -The outshy

put amplitude is controlled by the MONITOR LEVEL control

10

MAINTENANCE

GENERAL

Most of the components used in the construction of RYCOM instruments are standard parts obtainable from local suppliers Precision components may be purchased from the manufacturer Special items may not be readily avail shyable from the manufacturer All replacement parts are available from RYCOM

For various reasons changes will occasionally appear in the instruction book text parts list and drawings Continued effort is being made to imshyprove circuitry and use better components During the test procedure inshydividual adjustments are made to obtain optimum operation Parts procureshyment difficulties occasiona ly require substitution of different but equivashylent parts

Normal maintenance involves replacement of tubes fuse and pilot lights

The frequency dial lights are accessible from the front by removing the knobs and black dial cover When replacing the frequency knob depress the comshypression spring washer to give sufficient torque for the desired feel in rotating the knob

To remove the instrument from the case for maintenance remove only the screws around the edge of the front panel

PARTS ORDERING

When ordering parts be sure to specify the instrument serial number as well as the instrument model number and individual part number and symbol This will insure receiving the correct replacement parts with a minimum of delay

METER TRACKING

The zero scale

adjust control is used for tracking the meter at -10 db on the

To check or reset meter tracking adjust the unit o on the meter Turn the attenuator up 10 db to Adjust meter zero screw for -10 if needed Turn readjust CAL 2 LEV for O Recheck -10

to measure a frequency read -10 on the meter attenuator dovm 10 db and

at

BASIC AMPLITUDE CALIBRATION

Tube replacement or aging may cause some error in meter indication which is not expected to be more than ~ db This can be corrected by basic recali shybration of the instrument as discussed in Calibration paragraph of the description and given in step form below

1st step a Connect an external signal of about 1500 - of 0 dbm

amplitude to the input connector (NOTE use a preshycision meter to determine the 0 dbm amplitude)

11

b Switch positions ATTENUATOR on 0 MONITOR on AM METER on ON BAND SEL on A SELECTIVITY on 50 FREQUENCY dial to give peak

indication on meter c Adjust CAL 2 LEV to give 0 on meter

2nd step a CAUTION do not change CAL 2 LEV b Switch positions

METER on CAL 1 BAND SELECTOR on CAL c Adjust CAL 1 LEV to give 0 on meter

3rd step a CAUTION do not change CAL 1 LEV or CAL 2 LEV b Switch positions

METER on ON MONITOR on M~

ATTENUATOR on CAL BAND SELECTOR on CAL SELECTIVITY on 50 shy

c Adjust FREQUENCY dial pointer to 10 on band A d Adjust CAL 2 TRIM for peak meter indication e Adjust CAL 3 control located on top of the chassis

behind the meter to give zero on the meter NOTE It is important to set the frequency dial pointer to 10

on A band in this step since adjustment of CAL 2 TRIM for peak meter indication calibrates the frequency dial

FREQUENCY CALIBRATION

Frequency recalibration is made at 1 KC each time CAL 2 TRIM control is adjusted for peak meter indication during calibration however if the frequency tuning drifts appreciably it may be desirable to recalibrate the bands t at are off and all lower frequency bands If CAL 2 TRIM gives a peak indication at either extreme of rotation (when planetary drive slips) the oscillator has drifted out of the range of the control and should be recalibrated

An accurate 1 to 160 KC oscillator or oscillator and counter will be required to recalibrate the frequency dial (main osc)

Remove the case turn on the power and allow the instrument to warm up for 30 minutes Connect the external oscillator to the INPUT jack Set its frequency as indicated in the chart below Set the CAL 2 TRIM control two turns from either limit Set the attenuator control to the level used BAND SELECTOR and frequency dial to the position indicated in the chart below Adjust the trimmer indicated in the chart to obtain a peak meter indication Do not change the position of CAL 2 TRIM until the CAL oscilmiddot shylator is checked below

AT BAND SEL FREQ DIAL ADJUST TRllIMER Level used F 90 KC F in 3019 osc

Y E 11E 40 KC i D 10 KC (or 0) D II

C II v 4 KC B 1I B 2 KC

A 1 KC (or 0) A Ii

CAL CAL 1 KC CAL (see below)

12

II

The capacitors in the local oscillator are accumulatively added to the cir shycuit as the BAND SELECTOR switch is rotated from F to CAL thus frequency calibration must be made in the order listed above Band D and A may be calibrated at zero using the local oscillator frequency For this the CampR BAL controls must be adjusted for an on scale indication Band D requires a slightly different zero balance adjustment than band A

Check the calibrate oscillator frequency as follows continuing from A band calibration Set the attenuator (AT) on CAL and BAND SELECTOR on CAL The meter should indicate a peak reading from the calibrate oscillator To check this remove the input signal set controls as given in the chart on the preshyceding page for CAL and rotate the FREQ pointer for peak meter indication The peak meter indication should occur at a frequency pointer position of 1 KC as set for band A If it does not recheck the band calibration If CAL still does not give a peak indication at 1 KC note how far off the frequency is on the dial and proceed with the next paragraph

CALIBRATE OSCILLATOR CALIBRATION

If the calibrate oscillator is no more than 25 cps off as indicated in the preceeding paragraph then pad the capacitor C69 to change the calibrate oscillator by the amount of the error If desired measure the frequency of the CAL oscillator at V7 pin 8 It should be approximately 970 cps This will vary from unit to unit Pad C69 capacitor to change the frequency

If the error is off several 100 cps the fault probably is an error in band calibration or faulty component in the local oscillator (3019)

FREQUENCY SCALE TRACKING

If the frequency tracking on anyone band is off appreciably it may be desired to readjust the appropriate components

Tracking of the DEampF bands is accomplished by changing the LC ratio of L3 to the capacitors in the tank circuit (F trimmer or C94 being the variable trimmers used for this) This is a common adjustment for all three bands normally performed on the F band Moving the last turn on the coil then compensating for the frequency change with nFn trimmer or C94 will change the tracking from 90 to 160 KC on the F band several hundred cycles When the last turn is in position cement it in place with Q dope Recalibrate frequency of D and E bands as previously given Retracking any of the above bands will require resetting and possibly retracking of the ABampC bands

Tracking of the ABampC bands is a common adjustment (normally performed on the C band) by adjusting the ratio of C92 to fiC trimmer C92 changes the band tracking as well as the oscillator frequency C trimmer primarily changes only the oscillator frequency

One method of adjusting the tracking is as follows

1 Connect an electronic counter to V2 pin 2 or 7 Set the frequency dial to 4 KC and BAND SELECTOR to HCII band Adjust trimmer for 504000hCU

cps

13

2 Rotate the frequency dial to 6 KC and note the frequency Adjust C92 to shift the oscillator frequency about 10 times the difference between the oscillator frequency and 506000 cps in the direction of needed corshyrection For example the oscillator reads 506025 cps Adjust I1C92 i to give an oscillator frequency of 250 cps less which is 505775 cps

3 Rotate the pointer to 4 KC and adjust nC1 trimmer for 504000 cps If ICi trimmer does not have enough range set it in mid-position and adshyjust the liFI trimmer This will require recalibrat ion of the iiFn band using C94 (do NOT use liF trimmer) after the llCi band tracking has been adjusted and the frequency of nB and AIi band set

4 Check frequency at 6 KC as in step 2 Repeat the adjustment of steps 2 and 3 if needed Remove the counter lead from V2 pin 2 and 7

5 Recalibrate frequency of C BampA bands as previously given Check IiC r

band tracking by measuring a 4 and 6 KC signal

IF STAGE RETUNING

In the event CAL 2 LEV amplitude cannot be turned high enough to calibrate the instrument tube replacement retuning the IF stage transformers or retuning the crystal filters will be necessary

Connect a signal of about 10 KC to the INPUT JACK Tune in the signal and adjust front panel controls for maximum meter indication with SELECTIVITY switch on 50 - Rotate the top and bottom slugs of T4 then T5 for maxshyimum meter indication Do not rotate T3 slugs

CRYSTAL FILTER RETUNING

Crystal filter transformers are Tl and T2 T3 is adjusted during the crystal filter retuning

A sweep frequency generator and dc coupled oscilloscope are required for proper crystal filter retuning These are special units and not normally available thus it is recommended that the instrument be returned to the factory if the crystal filter needs retuning

If equipment as described below is available and it is desired to retune the crystal filter v-rri te the factory for instructions

1 A sweep frequency generator with center frequency between 20 and 160 KC and sweep width adjustable from about 250 cps to 30 KC It should have a repetition rate of about 2 seconds and output amplitude of approximately 01 volt

2 A direct coupled oscilloscope with a long persistence screen

14

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

MODEL 2174A FUNCTIONAL BLOCK DESIGN

BAND WIDTH DBM

~ IN

~ J t DEM-1400KC

Fe 450KC

500 to

900KC

FILTER RESPONSE CURVES MODEL 2174A

I

I I I I

I

I

I

50 CPS ~ I 10 CPS ~ I

I

I

J

jJ

II I 1 I v-I I

I ~ I

I I middot ~

I middot middot

bull IDlt 1100 I v

J~ i I I I v )-

1

1h I

bull

I

lIC

I I

I

II

10 bull

II

200 110 0 1110 200 bull Il 11 II J 5 bull ] 2 I 1 2 J bull 5 J It 11 bull4 ) 1 1 I 12) ampFREQUENCY IN CHIS 1I(QI(I I KILltTeliS UIIpoundltf II IllOCYCLES IlpoundaUIC II IILlCfCUS

I I

l y i i Ille 1middot1 I 1 V bull 1 III

bullKI t bull I ~ 4 3 2 I D 1 2 J 4 5 i 1

II

II

II

ltBandwidth 50 CYCLE FILTER

6db - 60 Cycles 60db - 450 Cycles 100 CYCLE FILTER Submit your requirements for special deviations from above instruments 6db - 140 Cycles

60d b - 900 Cycles 3KC FILTER

3db - 2140 Cycles 45db - 4200 Cycles 10KC FILTER

3d b - 4460 Cycles 45db - 24950 Cycles

Average Measure

A Division of

RAILWAY COMMUNICATIONS INC 9351 E59TH STREET RAYTOWN MISSOURI

Phone Code 816-FLeming 3-2100

Printed in U S A

INSPECTION

This instrument has been thoroughly tested and inspected before shipment

The instrument should be inspected for damage as soon as it is received If no damage is apparent test for operation according to operating instrucshytions in this manual

SU~~Y

The Selective Voltmeter is a highly selective instrument for m~king voltage measurements of frequencies from 3 to 160 kc varying in level from -90 to +32 dbm (30 volts maximum without external attenuator) Zero dbm reference is 1 milliwatt of power (or 775 volts) in a 600Q load The input signalis attenuated to the proper value by the attenuator amplified and demodushylated to 500 kc by a shunt type demodulator and variable oscillator This 500 kc signal passes through a sharp crystal filter then is amplified and detected The dc output is applied to a 200 microampere meter The meter has dbm and voltage scales and is calibrated to indicate the signal level at the instruments input connector

A wide crystal filter or broad tuning may be selected for monitoring~ In this use the SOO kc amplifier output is demodulated by a shunt type demodushylator and crystal oscillator for upper or lower sidebands by a conventional diode detector for ~I signals or by slope detection of FM signals The monitor output is to a speaker or headset jack An internal calibratingcircuit is provided so calibration can be made or checked as desired

DESCRIPTION

GENERAL

All symbols referred to such as (Vl) (X9) (RS3) or capitalized such as CAL 1 LEV or METER are stamped on the chassis or front panel of the instrument andor used in the schematic drawing

The input circuit contains a condenser (Cl) to block DC potentials a transshyformer in the input of 3002 filter so that measurements can be made on balshyanced circuits a 400 kilocycle lowpass filter (3002) and an attenuator The input impedance and balance or unbalance is controlled by UNBAL-BAL switch (Sl) The ATTENUATOR properly adjusts the input signal applied to Vl and has a CAL position used in calibrating the instrument The isolashytion amplifier (Vl) feeds a shunt type balanced demodulator (V2) whose balshyance is controlled by MOD BAL controls C amp R A variable frequency LC osshycillator ( V3) and phase inverter ( V3) supplies carrier frequency for demodulation This frequency is controlled by the main tuning condenser (C36) BAND SEL switch (S3) and a trimmer condenser (e83) CAL 2 TRIM The 50 cps or 3 kc crystal filter (Xl through X4 amp Tl or XS through X8 amp T2) or 10 kc broad coupling (C26 and 29) passes the lower sideband of demodulashytion The SOO kc IF amplifier (V4amp VS) feeds both the measure (~6~ D3-4~ and monitor (V8 9 amp 10) sections of the instrument The IF amp11f1er ga1n is adjusted by CAL 2 LEV (R37) The meter circuit amplifier (Vo) feeds a series shunt type meter rectifier (D3 amp D4) whose output indicates on a 200 microampere meter calibrated in dbm and volts

1

The amplifier (V8) feeds a series type demodulator (Dl D2) for monitoringlower sideband (LSB) or upper sideband (USB) signals The carrier for this demodulator is supplied by a crystal controlled oscillator ( V9) For monshyitoring amplitude modulated signals or slope detection of FM signals this oscillator is made inoperative and diode D2 removed thus the circuit opershyates as a conventional diode detector The resulting audio signal passes through the RC filter (R40 C57 C58) and amplifier ( V9 VIa) to the speaker or a headset plugged into the HEADSET jack (J3) The audio output amplitude is controlled by the potentiometer ~10N LEV (R42)

An audio signal may be amplified by inserting it in the AUDIO IN jack (if provided) just ahead of the audio amplifier ( V9 amp VIO)

A self contained calibration oscillator ( V7) is coupled to a cathode folshylower (A V7) whose output is adjusted by the potentiometer CAL 1 LEV (R55)

Plate power is furnished by a bridge type full wave selenium rectifier (SRI) A voltage regulator tube (Vll) stabilizes the plate supply to all cir shycuits except the monitor section

To prevent heater to cathode leakage and to lower 60 cps modulation (particshyularly in VI amp V2) the filaments are 50 volts DC above ground (R5-8 C9-10) 60 c~s modulation is further reduced by operating VI filament from a DC supshyply (C99middot- 101 SR5 SR6 R72)

INPUT

An input impedance of 135Q 600Q or bridging may be selected by the UNBALshyBAL switch (Sl) This switch also changes the input circuit from unbalanced to balanced on any impedance The BRIDGE input impedance is approxima~elyen 10000 ohms from 1 to 30 kc gradually falling to approximately 8000 ohms at 160 kc

An input impedance of 150 ohms instead of 135 ohms may be obtained by reshymoving resistor R3

Frequencies to be measured are connected to the INPUT connector (Jl) Both sides of the connector are insulated from the front panel thus isolating it from chassis ground during balanced measurements

ATTENUATOR

The attenuator provides 0 to 100 db of attenuation for measuring signals between -68 and +32 dbm (full scale meter indication)

The CAL position is connected to the voltage divider of the calibrate oscil shylator output for calibrating the isolation and IF amplifiers

LOCAL OSCILLATOR (3019)

The local oscillator (3019) is a hartley type using i of tube V3 The tank circuit consists of coil L3 and capacitors C36 C40 through C49C83C84 C88 amp C9l through C95 Capacitor C36 is the main tuning capacitor The even numbered capacitors C40 through C48 amp C88 are the trimmer capacitors

2

for calibrating each band Coil L3 and capacitor C92 are used to set freqshyuency tracking Capacitor C83 (CAL TRn~) is a front panel control affectshying all bands and is used for frequency calibration utilizing the self-conshytained calibrate oscillator as a standard

The local oscillator is varied from 5003 to 660 kilocycles by BAND SEL s~itch and the main tuning cap to measure frequencies of 3 to 160 kiloshycycles respectively as indicated on the frequency dial For example a Gignal of 1 kc is fed into the instrument The BAND SEL switch is set on i~ and frequency dial tuned to 10 kc The local oscillator is now oscillashyting at 501 kc and the lower sideband of demodulation is 500 kc which is the center frequency of the crystal filter

The oscillator half of V3 feeds the phase inverter half of V3 which provides 2pproximately equal potential (about 2 volts) to a plate and cathode of the demodulator tube V2 Potentiometers R25 (screwdriver control inside 3019 assy) and R24 (R MOD BAL on front panel) and capacitors C81 (screwdriver triwner inside 3019 assy) and C80 (C MOD BAL on front panel) adjusts the resistive and capacitive components in the demodulator circuit to give a minimum of oscillator potential at the cathode-plate junction of V2 (pins 1 amp 2) Balancing of the demodulator becomes critical only when the local oscillator frequency approaches the passband of the crystal filter (ie 500 kc) vfuen the oscillator is at 500 kc and the potential at V2 pin 1 amp 2 is balanced to the equivalent of -80 db at the input terminals the meter will indicate -10 As the oscillator frequency is increased the upper side of the crystal filter helps lower the local oscillator frequency potential that reaches the meter The narrow crystal filter rejection band provides at least 80 db of attenuation thus precise balance is not necessary except for measuring low frequencies The Demodulator Balance ii paragraph of 110perating Instructions 17 gives further details

The local oscillator is calibrated by feeding a known frequency into the instrument setting the frequency dial on the correct dial calibration and adjusting the band trimmer capacitor to obtain a peak meter indication

During operationcalibration at 1000 cps can be made using front panel conshytrols only For this the self-contained calibrate oscillator frequency is fed into VI the frequency dial is set at 1 kc and the meter indication peaked using CAL 2 TRn~

CALIBRATE OSCILLATOR

The calibrate oscillator is a hartley oscillator using of tube V7 It is ~oupled to a cathode follower (~ V7) whose output is adjusted by the potenshytiometer CAL 1 LEV (R55) Plate power is supplied to the calibrate oscilshylator only when the BAND SEL switch is in the CAL position thus it operates only during calibration This oscillator supplies potential for both amplishytude and frequency calibration as given in the calibration paragraph The calibrate oscillator is approximately 970 cps and calibrates the unit at 1000 cps (10 on band A) The difference in frequency compensates for capshyacity change in the BAND SEL switch when rotated from A to CAL

3

bull

SELECTIVITY

The SELECTIVITY switch is used to select one of three filters at the demodshyulator output The position marked 50 - selects a sharp crystal filter for measuring The position marked 3 KC selects a filter of appropriate width for demodulating 3 or 4 kc single sideband voice channels The position marked 10 KC selects mers determine the bathe back of the book

a n

coupling network dwidth of this position

to the IF amplifier whose The response curves

transforshyare in

D1QNITOR

The control marked MONITOR is an on-off switch for the AC power to the inshystrument and the gain control of the audio amplifier of the monitor section The USB position of the MONITOR switch connects a 50147 kc crystal to the monitor oscillator for demodulating upper sideband signals The LSB posishytion connects a 48953 kc crystal to the oscillator for demodulating lower sideband signals The AM position disconnects the plate power to the oscilshylator and disconnects diode D2 thus converting the series type demodulator to a diode detector The AM position is for monitoring amplitude or freqshyuency modulated voice channels or signals

METER SilJITCH

The t~TER switch (S5) controls the input to the meter circuit (V6 D3 amp D4 and meter) The OFF position shorts the meter input terminals to prevent pinning the needle while monitoring weak signals The ON position connects the IF amplifier output to the meter circuit for measuring and for the secshyond step of calibration The CAL 1 position connects the calibrate oscilshylator output to the meter for the first step of calibration

CALIBRATION

INTERNAL CALIBRATION amplitude and frequency Internal calibration calshyibrates the frequency dial and voltage (or DB) meter indication This is done entirely with front panel controls utilizing the self-contained calshyibrate oscillator and precision voltage divider for standards Step-byshystep procedure is given in the operating instructions

Internal calibration is accomplished in two steps The first step consists of feeding the calibrate oscillator output direct to the meter stage and adjusting the oscillator output (CAL 1 LEV) to give any desired meter indishycation (usually 0) The first part of the second step calibrates the freqshyuency It consists of rotating the FREQUENCY dial pointer to 10 on the A band and adjusting the CAL 2 TRIM control for a peak meter indication This adjustment tunes the local oscillator to the correct frequency for receivshying 1000 cps The second part of the second step calibrates the gain of the amplifiers to give proper meter indication This consists of feeding the calibrate oscillator output through the precision voltage divider (R57-R60 and attenuator CAL position) isolation amp Vl~ IF amp W4-V5) to the meter stage and adjusting the IF amp gain (CAL 2 LEV) to give the same meter inshydication set in step 1 This sets the isolation and IF amplifier gain equal to the loss in the precision voltage divider

4

BASIC CALIBRATION amplitude Basic calibration adjusts the precision voltage divider (R57-R60 and attenuator CAL position) to give the correct voltage (or DB) indication on the meter using an accurate external source as a standard This adjustment is made at the factory It can be checked and readjusted (CAL 3) if necessary as given in the maintenance section

Basic calibration consists of feeding 0 dbm into the input of the instrument and adjusting CAL 2 LEV (R37) to give zero on the meter Next the calibrate oscillator output is fed directly to the meter and adjusted by CAL 1 LEV to give 0 on the meter It is then fed through the isolation amplifier (VI) IF amp (V45 to the meter stage and CAL 3 (R58) is adjusted for 0 meter indication This adjusts the loss in the voltage divider to a value equal to the gain required in the amplifiers to give a correct meter indication

FREQUENCY BAND CALIBRATION using external frequency source The coil L3 is trimmed to set the tracking of the DE amp F bands The capacitor C92 is adjusted to set the tracking of the AB amp C bands Tracking is normally set on the F and C bands Anyone frequency on each band may be calibrated by feeding a known frequency into the instrument and adjusting trimmers C88 and C48 through C40 each for the proper band The band trimmers are progresshysively added to the tank circuit thus adjustment must be made in order from the F band to the A band Details for frequency band calibration are given in the maintenance section

5

OPERATING INSTRUCTIONS

GENERAL

Operation of the Selective Voltmeter is divided into two major functions that of measuring signals as indicated by the meter and that of monitoring carrier and audio voice bands or signals

All controls signal input audio input and output jacks and power connecshytions are on the front panel of the portable instrument Input output and power connections may be on the back of the rack mounted instrument

The power required is 48 watts 50 to 400 cps 115 volts Connection is made to the instrument with the cord furnished in the receptacle (AC) The power switch is located on the MONITOR LEVEL control where the off position is inshydicated (AC OFF)

DEMODULATOR BALANCE

Balance the demodulator as follows with the input signal disconnected (for measuring frequency below 1 kc)

a Switch positions BAND SEL on A or B FREQUENCY dial near 0 SELECTIVITY on 50 shy METER on ON MONITOR LEVEL on minimum

b Adjust MOD BAL controls C and R to obtain a mlnlmum meter reading NOTE If meter reads off scale adjust FREQUENCY dial up scale for full scale meter reading adjust C and R for preliminary balshyance (minimum meter reading) Return FREQUENCY dial to zero freqshyuency (maximum meter reading) and rebalance Repeat if necessary At final balance it should be possible to tune across 0 frequency with an on scale meter reading

c If a balance cannot be obtained within the limits (see note cl) of the CampR control on the front panel adjust the coarse CampR balance controls (see note c2) Set the CampR front panel controls in mid-range and adjust CampR coarse controls until an on scale balance is obtained Complete the balance with the front panel controls

Note cl The MOD BAL CampR controls have ball planetary drives R has a 10-turn control and C has a 4-turn control The limits of rotation are indicated when the drive slips at one extreme of rotation Note c2 Remove the unit from the case and locate the main oscillator assembly (3019) under the chassis Adjust the capacitor and potentiometer controls through the holes marked CampR

The degree of balance needed is dependent on the selectivity of the crystal filter and the frequency measured

6

L

The 50 cps crystal filter is down more than 20 db at 200 cps off and 60 db at 250 cps off thus a 0 db balance will cause negligible error when measuring a 300 cps or higher tone

A quick check is to tune in the desired signal remove the input and observe the meter reading due to carrier If it is less than an estimated -25 db tlen any reading above -10 db will be affected less than 1 db NOTE Do nnt set the meter zero on 0 volts The meter zero is used for meter trackshyi~g at -10 db

At low balance a double peak or erratic meter fluctuations may be noted These do not necessarily indicate trouble if the instrument performs satshyisfactorily when measuring a tone

The tube used as VI is critical in determining the degree of balance obtainshyable principally due to heater to cathode leakage Select a 6BH6 tube or a 66616BH6 to give best balance

INTERNAL CALIBRATION

Calibrate the instrument as follows for direct reading in dbm for the cir shycuit impedances listed Calibration for all impedances are based on 0 dbm equals 1 milliwatt of power Step CAL 2b calibrates the frequency Step CAL 2c calibrates the amplitude (meter db or voltage indication) Note Amplitude calibration is not essential for frequency calibration however frequency calibration is essential for amplitude calibration

CAL 1 a Switch positions

BAND SELECTOR to CAL ATTENUATOR to CAL METER to CAL 1 b Adjust CAL 1 LEVEL to give zero on meter DB scale for a 600Q

circuit For other circuit impedances adjust CAL 1 LEVEL to the following meter indications

(1) (3)

-6 for 150Q circuit -67 db for 130Q circuit

(2) (4)

-65 db -90 db

for 135Q circuit for 75Q circuit

CAL 2 a Switch positions

BAND SELECTOR to CAL METER to ON MONITOR to AM ATTEW0ATOR to CAL SELECTIVITY to 50 -

b Adjust FREQUENCY dial pointer to 10 on A band c d

AdjustAdjust

CAL CAL

2 TRIM to peak meter (this calibrates VAR OSC 2 LEV to give zero on meter DB scale for ALL

frequenc~)

circuit impedances (this calibrates amplitude)

This completes the calibration and the instrument is ready for use When precise measurements are needed it is recormnended that a calibration reshycheck be made during the warmup period See APPENDIX A for precautions

INPUT CIRCUIT SELECTION

The input may be unbalanced or balanced for an input impedance of 135Q 600Q or bridging as selected by the UNBAL-BAL switch The input jack on a standard unit takes a 34 spaced dual banana plug Other input conshynector types are supplied when so ordered

7

FREQUENCY SELECTION

Frequency selection is made by means of the BAND SELECTOR FREQUENCY and SELECTIVITY controls The frequency to be measured is tuned in by the large center knob and position ABC etc of the BAND SELECTOR switch

SELECTIVITY

The SELECTDIITY switch selects the crystal filter bandwidth to be used The 50 cycle position is normally used for measuring and the 3 KC and 10 KC for monitoring h~ere signals are spaced wide enough or circuit noise is low enough the 3 or 10 KC positions may be used for measuring above 3 to 6 KC or 10 to 20 KC respectively For precise measurements the internal cali shybration must be for the selectivity position to be used

AMPLITUDE MEASURElVIENT

Connect the signal to be measured to the INPUT JACK (CAUTION See overshyload paragraph) a Switch positions

BAND SELECTOR to desired band SELECTIVITY to 50 shyATTENUATOR to proper level MONITOR to AM (for precise METER to ON measurements)

b Adjust FREQUENCY dial to desired frequency and for maximum meter indication

c Add meter indication and attenuator position algebraically to obtain amplitude of signal being measured

LOW FREQUENCY ffiASUREMENTS

Measurements below about 500 cps require certain precautions The demodushylator must be balanced as given in the Demodulator Balance paragraph to prevent erroneous meter indication due to carrier leak Odd harmonics of 60 cps indicate on the meter due to internal coupling in the unit thus give a beat and cause erroneous meter indication when attempting to measure 60 and 180 cps etc The input impedance below 1 KC with the UNBAL-BAL switch on the l35Q (or below 300 cps on 600Q position) increases due to the impedance ratio of Cl to R2 amp R3 If 135Q or 600Q impedance is desired at low frequencies use the BRIDGE impedance position and an external 135Q or 600Q terminating resistor

OVERLOAD

The amplifiers of this instrument overload before the meter movement is damaged on moderate overloads--however excessive or prolonged overloads should be avoided

Amplitudes of +20 dbm or higher should not be left applied to the instrushyment for longer than a minute or two since the input circuit may heat If +20 dbm or higher amplitude is to be connected continuously a suitable pad should be connected ahead of the instrument to reduce the level below +20 dbm

LOW AMPLITUDE SIGNALS IN PRESENCE OF HIGH AMPLITUDE SIGNALS

Overloading is reduced by introducing attenuation to the input signals Therefore when measuring a low level signal when high levels are also present the more accurate reading will be made when the attenuator step is selected to give a meter reading on the lower 10 db section of the meter scale vfuen measuring circuits on which amplitudes are not approximately known it is suggested that the entire spectrum be first scanned to detershyTIline the highest amplitude signals present This will indicate the lowest level signals which may be apoundcurately measured When highest to lowest ~~els exceed 45 db some inaccuracy due to overload or intermodulation may JG 3usp~cted When measuring harmonics of a single frequency input accurshyate readings may be made 50 db or less for 2nd and 60 db or less for 3rd hi~rmonics

In any case when a low level signal is being measured if the attenuator switch is changed by 10 db and the meter reading also changes 10 db the measurement can be considered accurate

vfuen many input signals are present no simple rule can be followed as the overload point is determined by the peak envelope of the combined signals which may vary with their amplitude and phase

CARRIER MONITORING

The Selective Voltmeter may be used to monitor lower sideband (LSB) upper sideband (USB) amplitude modulated (AM) or frequency modulated (FM)signals Use the 3 kc position of SELECTIVITY switch above 3 kc only and the 10 kc position above 10 kc only

1 Upper and lower sideband monitoring a Connect the input connector to the circuit to be monitored b Switch positions

SELECTIVITY to 3 KC BAND SEL switch amp FREQUENCY DIAL to midband frequency of the

sideband MONITOR switch to LSB or USB as required MONITOR LEVEL--adjust as needed

If the voice or signal from the speaker (or headset if used in HEADSET jack) is weak turn the I1ETER switch off and the ATTENUATOR down until the desired level is reached

2 AM monitoring

To monitor AM signals feed the signal in the INPUT connector turn the seshylectivity to 3 kc or 10 kc set the MONITOR switch to AM tune the FREQshyUENCY dial to the carrier frequency and adjust the amplitude as for single sideband signals

3 FM monitoring

To monitor FM signals by slope detection feed the signal in the INPUT conshynector turn the SELECTIVITY switch to 10 kc set the MONITOR switch to AM adjust the frequency dial for best reception (one side of thA selectivity curve) and adjust the aDlplitude as for single sideband signals

9

AUDIO MONITORING (on units with AUDIO IN jack)

The audio section of the monitor circuit may be used as a amplifier if desired by inserting the signal in the AUDIO

voice frequency IN jack -The outshy

put amplitude is controlled by the MONITOR LEVEL control

10

MAINTENANCE

GENERAL

Most of the components used in the construction of RYCOM instruments are standard parts obtainable from local suppliers Precision components may be purchased from the manufacturer Special items may not be readily avail shyable from the manufacturer All replacement parts are available from RYCOM

For various reasons changes will occasionally appear in the instruction book text parts list and drawings Continued effort is being made to imshyprove circuitry and use better components During the test procedure inshydividual adjustments are made to obtain optimum operation Parts procureshyment difficulties occasiona ly require substitution of different but equivashylent parts

Normal maintenance involves replacement of tubes fuse and pilot lights

The frequency dial lights are accessible from the front by removing the knobs and black dial cover When replacing the frequency knob depress the comshypression spring washer to give sufficient torque for the desired feel in rotating the knob

To remove the instrument from the case for maintenance remove only the screws around the edge of the front panel

PARTS ORDERING

When ordering parts be sure to specify the instrument serial number as well as the instrument model number and individual part number and symbol This will insure receiving the correct replacement parts with a minimum of delay

METER TRACKING

The zero scale

adjust control is used for tracking the meter at -10 db on the

To check or reset meter tracking adjust the unit o on the meter Turn the attenuator up 10 db to Adjust meter zero screw for -10 if needed Turn readjust CAL 2 LEV for O Recheck -10

to measure a frequency read -10 on the meter attenuator dovm 10 db and

at

BASIC AMPLITUDE CALIBRATION

Tube replacement or aging may cause some error in meter indication which is not expected to be more than ~ db This can be corrected by basic recali shybration of the instrument as discussed in Calibration paragraph of the description and given in step form below

1st step a Connect an external signal of about 1500 - of 0 dbm

amplitude to the input connector (NOTE use a preshycision meter to determine the 0 dbm amplitude)

11

b Switch positions ATTENUATOR on 0 MONITOR on AM METER on ON BAND SEL on A SELECTIVITY on 50 FREQUENCY dial to give peak

indication on meter c Adjust CAL 2 LEV to give 0 on meter

2nd step a CAUTION do not change CAL 2 LEV b Switch positions

METER on CAL 1 BAND SELECTOR on CAL c Adjust CAL 1 LEV to give 0 on meter

3rd step a CAUTION do not change CAL 1 LEV or CAL 2 LEV b Switch positions

METER on ON MONITOR on M~

ATTENUATOR on CAL BAND SELECTOR on CAL SELECTIVITY on 50 shy

c Adjust FREQUENCY dial pointer to 10 on band A d Adjust CAL 2 TRIM for peak meter indication e Adjust CAL 3 control located on top of the chassis

behind the meter to give zero on the meter NOTE It is important to set the frequency dial pointer to 10

on A band in this step since adjustment of CAL 2 TRIM for peak meter indication calibrates the frequency dial

FREQUENCY CALIBRATION

Frequency recalibration is made at 1 KC each time CAL 2 TRIM control is adjusted for peak meter indication during calibration however if the frequency tuning drifts appreciably it may be desirable to recalibrate the bands t at are off and all lower frequency bands If CAL 2 TRIM gives a peak indication at either extreme of rotation (when planetary drive slips) the oscillator has drifted out of the range of the control and should be recalibrated

An accurate 1 to 160 KC oscillator or oscillator and counter will be required to recalibrate the frequency dial (main osc)

Remove the case turn on the power and allow the instrument to warm up for 30 minutes Connect the external oscillator to the INPUT jack Set its frequency as indicated in the chart below Set the CAL 2 TRIM control two turns from either limit Set the attenuator control to the level used BAND SELECTOR and frequency dial to the position indicated in the chart below Adjust the trimmer indicated in the chart to obtain a peak meter indication Do not change the position of CAL 2 TRIM until the CAL oscilmiddot shylator is checked below

AT BAND SEL FREQ DIAL ADJUST TRllIMER Level used F 90 KC F in 3019 osc

Y E 11E 40 KC i D 10 KC (or 0) D II

C II v 4 KC B 1I B 2 KC

A 1 KC (or 0) A Ii

CAL CAL 1 KC CAL (see below)

12

II

The capacitors in the local oscillator are accumulatively added to the cir shycuit as the BAND SELECTOR switch is rotated from F to CAL thus frequency calibration must be made in the order listed above Band D and A may be calibrated at zero using the local oscillator frequency For this the CampR BAL controls must be adjusted for an on scale indication Band D requires a slightly different zero balance adjustment than band A

Check the calibrate oscillator frequency as follows continuing from A band calibration Set the attenuator (AT) on CAL and BAND SELECTOR on CAL The meter should indicate a peak reading from the calibrate oscillator To check this remove the input signal set controls as given in the chart on the preshyceding page for CAL and rotate the FREQ pointer for peak meter indication The peak meter indication should occur at a frequency pointer position of 1 KC as set for band A If it does not recheck the band calibration If CAL still does not give a peak indication at 1 KC note how far off the frequency is on the dial and proceed with the next paragraph

CALIBRATE OSCILLATOR CALIBRATION

If the calibrate oscillator is no more than 25 cps off as indicated in the preceeding paragraph then pad the capacitor C69 to change the calibrate oscillator by the amount of the error If desired measure the frequency of the CAL oscillator at V7 pin 8 It should be approximately 970 cps This will vary from unit to unit Pad C69 capacitor to change the frequency

If the error is off several 100 cps the fault probably is an error in band calibration or faulty component in the local oscillator (3019)

FREQUENCY SCALE TRACKING

If the frequency tracking on anyone band is off appreciably it may be desired to readjust the appropriate components

Tracking of the DEampF bands is accomplished by changing the LC ratio of L3 to the capacitors in the tank circuit (F trimmer or C94 being the variable trimmers used for this) This is a common adjustment for all three bands normally performed on the F band Moving the last turn on the coil then compensating for the frequency change with nFn trimmer or C94 will change the tracking from 90 to 160 KC on the F band several hundred cycles When the last turn is in position cement it in place with Q dope Recalibrate frequency of D and E bands as previously given Retracking any of the above bands will require resetting and possibly retracking of the ABampC bands

Tracking of the ABampC bands is a common adjustment (normally performed on the C band) by adjusting the ratio of C92 to fiC trimmer C92 changes the band tracking as well as the oscillator frequency C trimmer primarily changes only the oscillator frequency

One method of adjusting the tracking is as follows

1 Connect an electronic counter to V2 pin 2 or 7 Set the frequency dial to 4 KC and BAND SELECTOR to HCII band Adjust trimmer for 504000hCU

cps

13

2 Rotate the frequency dial to 6 KC and note the frequency Adjust C92 to shift the oscillator frequency about 10 times the difference between the oscillator frequency and 506000 cps in the direction of needed corshyrection For example the oscillator reads 506025 cps Adjust I1C92 i to give an oscillator frequency of 250 cps less which is 505775 cps

3 Rotate the pointer to 4 KC and adjust nC1 trimmer for 504000 cps If ICi trimmer does not have enough range set it in mid-position and adshyjust the liFI trimmer This will require recalibrat ion of the iiFn band using C94 (do NOT use liF trimmer) after the llCi band tracking has been adjusted and the frequency of nB and AIi band set

4 Check frequency at 6 KC as in step 2 Repeat the adjustment of steps 2 and 3 if needed Remove the counter lead from V2 pin 2 and 7

5 Recalibrate frequency of C BampA bands as previously given Check IiC r

band tracking by measuring a 4 and 6 KC signal

IF STAGE RETUNING

In the event CAL 2 LEV amplitude cannot be turned high enough to calibrate the instrument tube replacement retuning the IF stage transformers or retuning the crystal filters will be necessary

Connect a signal of about 10 KC to the INPUT JACK Tune in the signal and adjust front panel controls for maximum meter indication with SELECTIVITY switch on 50 - Rotate the top and bottom slugs of T4 then T5 for maxshyimum meter indication Do not rotate T3 slugs

CRYSTAL FILTER RETUNING

Crystal filter transformers are Tl and T2 T3 is adjusted during the crystal filter retuning

A sweep frequency generator and dc coupled oscilloscope are required for proper crystal filter retuning These are special units and not normally available thus it is recommended that the instrument be returned to the factory if the crystal filter needs retuning

If equipment as described below is available and it is desired to retune the crystal filter v-rri te the factory for instructions

1 A sweep frequency generator with center frequency between 20 and 160 KC and sweep width adjustable from about 250 cps to 30 KC It should have a repetition rate of about 2 seconds and output amplitude of approximately 01 volt

2 A direct coupled oscilloscope with a long persistence screen

14

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

INSPECTION

This instrument has been thoroughly tested and inspected before shipment

The instrument should be inspected for damage as soon as it is received If no damage is apparent test for operation according to operating instrucshytions in this manual

SU~~Y

The Selective Voltmeter is a highly selective instrument for m~king voltage measurements of frequencies from 3 to 160 kc varying in level from -90 to +32 dbm (30 volts maximum without external attenuator) Zero dbm reference is 1 milliwatt of power (or 775 volts) in a 600Q load The input signalis attenuated to the proper value by the attenuator amplified and demodushylated to 500 kc by a shunt type demodulator and variable oscillator This 500 kc signal passes through a sharp crystal filter then is amplified and detected The dc output is applied to a 200 microampere meter The meter has dbm and voltage scales and is calibrated to indicate the signal level at the instruments input connector

A wide crystal filter or broad tuning may be selected for monitoring~ In this use the SOO kc amplifier output is demodulated by a shunt type demodushylator and crystal oscillator for upper or lower sidebands by a conventional diode detector for ~I signals or by slope detection of FM signals The monitor output is to a speaker or headset jack An internal calibratingcircuit is provided so calibration can be made or checked as desired

DESCRIPTION

GENERAL

All symbols referred to such as (Vl) (X9) (RS3) or capitalized such as CAL 1 LEV or METER are stamped on the chassis or front panel of the instrument andor used in the schematic drawing

The input circuit contains a condenser (Cl) to block DC potentials a transshyformer in the input of 3002 filter so that measurements can be made on balshyanced circuits a 400 kilocycle lowpass filter (3002) and an attenuator The input impedance and balance or unbalance is controlled by UNBAL-BAL switch (Sl) The ATTENUATOR properly adjusts the input signal applied to Vl and has a CAL position used in calibrating the instrument The isolashytion amplifier (Vl) feeds a shunt type balanced demodulator (V2) whose balshyance is controlled by MOD BAL controls C amp R A variable frequency LC osshycillator ( V3) and phase inverter ( V3) supplies carrier frequency for demodulation This frequency is controlled by the main tuning condenser (C36) BAND SEL switch (S3) and a trimmer condenser (e83) CAL 2 TRIM The 50 cps or 3 kc crystal filter (Xl through X4 amp Tl or XS through X8 amp T2) or 10 kc broad coupling (C26 and 29) passes the lower sideband of demodulashytion The SOO kc IF amplifier (V4amp VS) feeds both the measure (~6~ D3-4~ and monitor (V8 9 amp 10) sections of the instrument The IF amp11f1er ga1n is adjusted by CAL 2 LEV (R37) The meter circuit amplifier (Vo) feeds a series shunt type meter rectifier (D3 amp D4) whose output indicates on a 200 microampere meter calibrated in dbm and volts

1

The amplifier (V8) feeds a series type demodulator (Dl D2) for monitoringlower sideband (LSB) or upper sideband (USB) signals The carrier for this demodulator is supplied by a crystal controlled oscillator ( V9) For monshyitoring amplitude modulated signals or slope detection of FM signals this oscillator is made inoperative and diode D2 removed thus the circuit opershyates as a conventional diode detector The resulting audio signal passes through the RC filter (R40 C57 C58) and amplifier ( V9 VIa) to the speaker or a headset plugged into the HEADSET jack (J3) The audio output amplitude is controlled by the potentiometer ~10N LEV (R42)

An audio signal may be amplified by inserting it in the AUDIO IN jack (if provided) just ahead of the audio amplifier ( V9 amp VIO)

A self contained calibration oscillator ( V7) is coupled to a cathode folshylower (A V7) whose output is adjusted by the potentiometer CAL 1 LEV (R55)

Plate power is furnished by a bridge type full wave selenium rectifier (SRI) A voltage regulator tube (Vll) stabilizes the plate supply to all cir shycuits except the monitor section

To prevent heater to cathode leakage and to lower 60 cps modulation (particshyularly in VI amp V2) the filaments are 50 volts DC above ground (R5-8 C9-10) 60 c~s modulation is further reduced by operating VI filament from a DC supshyply (C99middot- 101 SR5 SR6 R72)

INPUT

An input impedance of 135Q 600Q or bridging may be selected by the UNBALshyBAL switch (Sl) This switch also changes the input circuit from unbalanced to balanced on any impedance The BRIDGE input impedance is approxima~elyen 10000 ohms from 1 to 30 kc gradually falling to approximately 8000 ohms at 160 kc

An input impedance of 150 ohms instead of 135 ohms may be obtained by reshymoving resistor R3

Frequencies to be measured are connected to the INPUT connector (Jl) Both sides of the connector are insulated from the front panel thus isolating it from chassis ground during balanced measurements

ATTENUATOR

The attenuator provides 0 to 100 db of attenuation for measuring signals between -68 and +32 dbm (full scale meter indication)

The CAL position is connected to the voltage divider of the calibrate oscil shylator output for calibrating the isolation and IF amplifiers

LOCAL OSCILLATOR (3019)

The local oscillator (3019) is a hartley type using i of tube V3 The tank circuit consists of coil L3 and capacitors C36 C40 through C49C83C84 C88 amp C9l through C95 Capacitor C36 is the main tuning capacitor The even numbered capacitors C40 through C48 amp C88 are the trimmer capacitors

2

for calibrating each band Coil L3 and capacitor C92 are used to set freqshyuency tracking Capacitor C83 (CAL TRn~) is a front panel control affectshying all bands and is used for frequency calibration utilizing the self-conshytained calibrate oscillator as a standard

The local oscillator is varied from 5003 to 660 kilocycles by BAND SEL s~itch and the main tuning cap to measure frequencies of 3 to 160 kiloshycycles respectively as indicated on the frequency dial For example a Gignal of 1 kc is fed into the instrument The BAND SEL switch is set on i~ and frequency dial tuned to 10 kc The local oscillator is now oscillashyting at 501 kc and the lower sideband of demodulation is 500 kc which is the center frequency of the crystal filter

The oscillator half of V3 feeds the phase inverter half of V3 which provides 2pproximately equal potential (about 2 volts) to a plate and cathode of the demodulator tube V2 Potentiometers R25 (screwdriver control inside 3019 assy) and R24 (R MOD BAL on front panel) and capacitors C81 (screwdriver triwner inside 3019 assy) and C80 (C MOD BAL on front panel) adjusts the resistive and capacitive components in the demodulator circuit to give a minimum of oscillator potential at the cathode-plate junction of V2 (pins 1 amp 2) Balancing of the demodulator becomes critical only when the local oscillator frequency approaches the passband of the crystal filter (ie 500 kc) vfuen the oscillator is at 500 kc and the potential at V2 pin 1 amp 2 is balanced to the equivalent of -80 db at the input terminals the meter will indicate -10 As the oscillator frequency is increased the upper side of the crystal filter helps lower the local oscillator frequency potential that reaches the meter The narrow crystal filter rejection band provides at least 80 db of attenuation thus precise balance is not necessary except for measuring low frequencies The Demodulator Balance ii paragraph of 110perating Instructions 17 gives further details

The local oscillator is calibrated by feeding a known frequency into the instrument setting the frequency dial on the correct dial calibration and adjusting the band trimmer capacitor to obtain a peak meter indication

During operationcalibration at 1000 cps can be made using front panel conshytrols only For this the self-contained calibrate oscillator frequency is fed into VI the frequency dial is set at 1 kc and the meter indication peaked using CAL 2 TRn~

CALIBRATE OSCILLATOR

The calibrate oscillator is a hartley oscillator using of tube V7 It is ~oupled to a cathode follower (~ V7) whose output is adjusted by the potenshytiometer CAL 1 LEV (R55) Plate power is supplied to the calibrate oscilshylator only when the BAND SEL switch is in the CAL position thus it operates only during calibration This oscillator supplies potential for both amplishytude and frequency calibration as given in the calibration paragraph The calibrate oscillator is approximately 970 cps and calibrates the unit at 1000 cps (10 on band A) The difference in frequency compensates for capshyacity change in the BAND SEL switch when rotated from A to CAL

3

bull

SELECTIVITY

The SELECTIVITY switch is used to select one of three filters at the demodshyulator output The position marked 50 - selects a sharp crystal filter for measuring The position marked 3 KC selects a filter of appropriate width for demodulating 3 or 4 kc single sideband voice channels The position marked 10 KC selects mers determine the bathe back of the book

a n

coupling network dwidth of this position

to the IF amplifier whose The response curves

transforshyare in

D1QNITOR

The control marked MONITOR is an on-off switch for the AC power to the inshystrument and the gain control of the audio amplifier of the monitor section The USB position of the MONITOR switch connects a 50147 kc crystal to the monitor oscillator for demodulating upper sideband signals The LSB posishytion connects a 48953 kc crystal to the oscillator for demodulating lower sideband signals The AM position disconnects the plate power to the oscilshylator and disconnects diode D2 thus converting the series type demodulator to a diode detector The AM position is for monitoring amplitude or freqshyuency modulated voice channels or signals

METER SilJITCH

The t~TER switch (S5) controls the input to the meter circuit (V6 D3 amp D4 and meter) The OFF position shorts the meter input terminals to prevent pinning the needle while monitoring weak signals The ON position connects the IF amplifier output to the meter circuit for measuring and for the secshyond step of calibration The CAL 1 position connects the calibrate oscilshylator output to the meter for the first step of calibration

CALIBRATION

INTERNAL CALIBRATION amplitude and frequency Internal calibration calshyibrates the frequency dial and voltage (or DB) meter indication This is done entirely with front panel controls utilizing the self-contained calshyibrate oscillator and precision voltage divider for standards Step-byshystep procedure is given in the operating instructions

Internal calibration is accomplished in two steps The first step consists of feeding the calibrate oscillator output direct to the meter stage and adjusting the oscillator output (CAL 1 LEV) to give any desired meter indishycation (usually 0) The first part of the second step calibrates the freqshyuency It consists of rotating the FREQUENCY dial pointer to 10 on the A band and adjusting the CAL 2 TRIM control for a peak meter indication This adjustment tunes the local oscillator to the correct frequency for receivshying 1000 cps The second part of the second step calibrates the gain of the amplifiers to give proper meter indication This consists of feeding the calibrate oscillator output through the precision voltage divider (R57-R60 and attenuator CAL position) isolation amp Vl~ IF amp W4-V5) to the meter stage and adjusting the IF amp gain (CAL 2 LEV) to give the same meter inshydication set in step 1 This sets the isolation and IF amplifier gain equal to the loss in the precision voltage divider

4

BASIC CALIBRATION amplitude Basic calibration adjusts the precision voltage divider (R57-R60 and attenuator CAL position) to give the correct voltage (or DB) indication on the meter using an accurate external source as a standard This adjustment is made at the factory It can be checked and readjusted (CAL 3) if necessary as given in the maintenance section

Basic calibration consists of feeding 0 dbm into the input of the instrument and adjusting CAL 2 LEV (R37) to give zero on the meter Next the calibrate oscillator output is fed directly to the meter and adjusted by CAL 1 LEV to give 0 on the meter It is then fed through the isolation amplifier (VI) IF amp (V45 to the meter stage and CAL 3 (R58) is adjusted for 0 meter indication This adjusts the loss in the voltage divider to a value equal to the gain required in the amplifiers to give a correct meter indication

FREQUENCY BAND CALIBRATION using external frequency source The coil L3 is trimmed to set the tracking of the DE amp F bands The capacitor C92 is adjusted to set the tracking of the AB amp C bands Tracking is normally set on the F and C bands Anyone frequency on each band may be calibrated by feeding a known frequency into the instrument and adjusting trimmers C88 and C48 through C40 each for the proper band The band trimmers are progresshysively added to the tank circuit thus adjustment must be made in order from the F band to the A band Details for frequency band calibration are given in the maintenance section

5

OPERATING INSTRUCTIONS

GENERAL

Operation of the Selective Voltmeter is divided into two major functions that of measuring signals as indicated by the meter and that of monitoring carrier and audio voice bands or signals

All controls signal input audio input and output jacks and power connecshytions are on the front panel of the portable instrument Input output and power connections may be on the back of the rack mounted instrument

The power required is 48 watts 50 to 400 cps 115 volts Connection is made to the instrument with the cord furnished in the receptacle (AC) The power switch is located on the MONITOR LEVEL control where the off position is inshydicated (AC OFF)

DEMODULATOR BALANCE

Balance the demodulator as follows with the input signal disconnected (for measuring frequency below 1 kc)

a Switch positions BAND SEL on A or B FREQUENCY dial near 0 SELECTIVITY on 50 shy METER on ON MONITOR LEVEL on minimum

b Adjust MOD BAL controls C and R to obtain a mlnlmum meter reading NOTE If meter reads off scale adjust FREQUENCY dial up scale for full scale meter reading adjust C and R for preliminary balshyance (minimum meter reading) Return FREQUENCY dial to zero freqshyuency (maximum meter reading) and rebalance Repeat if necessary At final balance it should be possible to tune across 0 frequency with an on scale meter reading

c If a balance cannot be obtained within the limits (see note cl) of the CampR control on the front panel adjust the coarse CampR balance controls (see note c2) Set the CampR front panel controls in mid-range and adjust CampR coarse controls until an on scale balance is obtained Complete the balance with the front panel controls

Note cl The MOD BAL CampR controls have ball planetary drives R has a 10-turn control and C has a 4-turn control The limits of rotation are indicated when the drive slips at one extreme of rotation Note c2 Remove the unit from the case and locate the main oscillator assembly (3019) under the chassis Adjust the capacitor and potentiometer controls through the holes marked CampR

The degree of balance needed is dependent on the selectivity of the crystal filter and the frequency measured

6

L

The 50 cps crystal filter is down more than 20 db at 200 cps off and 60 db at 250 cps off thus a 0 db balance will cause negligible error when measuring a 300 cps or higher tone

A quick check is to tune in the desired signal remove the input and observe the meter reading due to carrier If it is less than an estimated -25 db tlen any reading above -10 db will be affected less than 1 db NOTE Do nnt set the meter zero on 0 volts The meter zero is used for meter trackshyi~g at -10 db

At low balance a double peak or erratic meter fluctuations may be noted These do not necessarily indicate trouble if the instrument performs satshyisfactorily when measuring a tone

The tube used as VI is critical in determining the degree of balance obtainshyable principally due to heater to cathode leakage Select a 6BH6 tube or a 66616BH6 to give best balance

INTERNAL CALIBRATION

Calibrate the instrument as follows for direct reading in dbm for the cir shycuit impedances listed Calibration for all impedances are based on 0 dbm equals 1 milliwatt of power Step CAL 2b calibrates the frequency Step CAL 2c calibrates the amplitude (meter db or voltage indication) Note Amplitude calibration is not essential for frequency calibration however frequency calibration is essential for amplitude calibration

CAL 1 a Switch positions

BAND SELECTOR to CAL ATTENUATOR to CAL METER to CAL 1 b Adjust CAL 1 LEVEL to give zero on meter DB scale for a 600Q

circuit For other circuit impedances adjust CAL 1 LEVEL to the following meter indications

(1) (3)

-6 for 150Q circuit -67 db for 130Q circuit

(2) (4)

-65 db -90 db

for 135Q circuit for 75Q circuit

CAL 2 a Switch positions

BAND SELECTOR to CAL METER to ON MONITOR to AM ATTEW0ATOR to CAL SELECTIVITY to 50 -

b Adjust FREQUENCY dial pointer to 10 on A band c d

AdjustAdjust

CAL CAL

2 TRIM to peak meter (this calibrates VAR OSC 2 LEV to give zero on meter DB scale for ALL

frequenc~)

circuit impedances (this calibrates amplitude)

This completes the calibration and the instrument is ready for use When precise measurements are needed it is recormnended that a calibration reshycheck be made during the warmup period See APPENDIX A for precautions

INPUT CIRCUIT SELECTION

The input may be unbalanced or balanced for an input impedance of 135Q 600Q or bridging as selected by the UNBAL-BAL switch The input jack on a standard unit takes a 34 spaced dual banana plug Other input conshynector types are supplied when so ordered

7

FREQUENCY SELECTION

Frequency selection is made by means of the BAND SELECTOR FREQUENCY and SELECTIVITY controls The frequency to be measured is tuned in by the large center knob and position ABC etc of the BAND SELECTOR switch

SELECTIVITY

The SELECTDIITY switch selects the crystal filter bandwidth to be used The 50 cycle position is normally used for measuring and the 3 KC and 10 KC for monitoring h~ere signals are spaced wide enough or circuit noise is low enough the 3 or 10 KC positions may be used for measuring above 3 to 6 KC or 10 to 20 KC respectively For precise measurements the internal cali shybration must be for the selectivity position to be used

AMPLITUDE MEASURElVIENT

Connect the signal to be measured to the INPUT JACK (CAUTION See overshyload paragraph) a Switch positions

BAND SELECTOR to desired band SELECTIVITY to 50 shyATTENUATOR to proper level MONITOR to AM (for precise METER to ON measurements)

b Adjust FREQUENCY dial to desired frequency and for maximum meter indication

c Add meter indication and attenuator position algebraically to obtain amplitude of signal being measured

LOW FREQUENCY ffiASUREMENTS

Measurements below about 500 cps require certain precautions The demodushylator must be balanced as given in the Demodulator Balance paragraph to prevent erroneous meter indication due to carrier leak Odd harmonics of 60 cps indicate on the meter due to internal coupling in the unit thus give a beat and cause erroneous meter indication when attempting to measure 60 and 180 cps etc The input impedance below 1 KC with the UNBAL-BAL switch on the l35Q (or below 300 cps on 600Q position) increases due to the impedance ratio of Cl to R2 amp R3 If 135Q or 600Q impedance is desired at low frequencies use the BRIDGE impedance position and an external 135Q or 600Q terminating resistor

OVERLOAD

The amplifiers of this instrument overload before the meter movement is damaged on moderate overloads--however excessive or prolonged overloads should be avoided

Amplitudes of +20 dbm or higher should not be left applied to the instrushyment for longer than a minute or two since the input circuit may heat If +20 dbm or higher amplitude is to be connected continuously a suitable pad should be connected ahead of the instrument to reduce the level below +20 dbm

LOW AMPLITUDE SIGNALS IN PRESENCE OF HIGH AMPLITUDE SIGNALS

Overloading is reduced by introducing attenuation to the input signals Therefore when measuring a low level signal when high levels are also present the more accurate reading will be made when the attenuator step is selected to give a meter reading on the lower 10 db section of the meter scale vfuen measuring circuits on which amplitudes are not approximately known it is suggested that the entire spectrum be first scanned to detershyTIline the highest amplitude signals present This will indicate the lowest level signals which may be apoundcurately measured When highest to lowest ~~els exceed 45 db some inaccuracy due to overload or intermodulation may JG 3usp~cted When measuring harmonics of a single frequency input accurshyate readings may be made 50 db or less for 2nd and 60 db or less for 3rd hi~rmonics

In any case when a low level signal is being measured if the attenuator switch is changed by 10 db and the meter reading also changes 10 db the measurement can be considered accurate

vfuen many input signals are present no simple rule can be followed as the overload point is determined by the peak envelope of the combined signals which may vary with their amplitude and phase

CARRIER MONITORING

The Selective Voltmeter may be used to monitor lower sideband (LSB) upper sideband (USB) amplitude modulated (AM) or frequency modulated (FM)signals Use the 3 kc position of SELECTIVITY switch above 3 kc only and the 10 kc position above 10 kc only

1 Upper and lower sideband monitoring a Connect the input connector to the circuit to be monitored b Switch positions

SELECTIVITY to 3 KC BAND SEL switch amp FREQUENCY DIAL to midband frequency of the

sideband MONITOR switch to LSB or USB as required MONITOR LEVEL--adjust as needed

If the voice or signal from the speaker (or headset if used in HEADSET jack) is weak turn the I1ETER switch off and the ATTENUATOR down until the desired level is reached

2 AM monitoring

To monitor AM signals feed the signal in the INPUT connector turn the seshylectivity to 3 kc or 10 kc set the MONITOR switch to AM tune the FREQshyUENCY dial to the carrier frequency and adjust the amplitude as for single sideband signals

3 FM monitoring

To monitor FM signals by slope detection feed the signal in the INPUT conshynector turn the SELECTIVITY switch to 10 kc set the MONITOR switch to AM adjust the frequency dial for best reception (one side of thA selectivity curve) and adjust the aDlplitude as for single sideband signals

9

AUDIO MONITORING (on units with AUDIO IN jack)

The audio section of the monitor circuit may be used as a amplifier if desired by inserting the signal in the AUDIO

voice frequency IN jack -The outshy

put amplitude is controlled by the MONITOR LEVEL control

10

MAINTENANCE

GENERAL

Most of the components used in the construction of RYCOM instruments are standard parts obtainable from local suppliers Precision components may be purchased from the manufacturer Special items may not be readily avail shyable from the manufacturer All replacement parts are available from RYCOM

For various reasons changes will occasionally appear in the instruction book text parts list and drawings Continued effort is being made to imshyprove circuitry and use better components During the test procedure inshydividual adjustments are made to obtain optimum operation Parts procureshyment difficulties occasiona ly require substitution of different but equivashylent parts

Normal maintenance involves replacement of tubes fuse and pilot lights

The frequency dial lights are accessible from the front by removing the knobs and black dial cover When replacing the frequency knob depress the comshypression spring washer to give sufficient torque for the desired feel in rotating the knob

To remove the instrument from the case for maintenance remove only the screws around the edge of the front panel

PARTS ORDERING

When ordering parts be sure to specify the instrument serial number as well as the instrument model number and individual part number and symbol This will insure receiving the correct replacement parts with a minimum of delay

METER TRACKING

The zero scale

adjust control is used for tracking the meter at -10 db on the

To check or reset meter tracking adjust the unit o on the meter Turn the attenuator up 10 db to Adjust meter zero screw for -10 if needed Turn readjust CAL 2 LEV for O Recheck -10

to measure a frequency read -10 on the meter attenuator dovm 10 db and

at

BASIC AMPLITUDE CALIBRATION

Tube replacement or aging may cause some error in meter indication which is not expected to be more than ~ db This can be corrected by basic recali shybration of the instrument as discussed in Calibration paragraph of the description and given in step form below

1st step a Connect an external signal of about 1500 - of 0 dbm

amplitude to the input connector (NOTE use a preshycision meter to determine the 0 dbm amplitude)

11

b Switch positions ATTENUATOR on 0 MONITOR on AM METER on ON BAND SEL on A SELECTIVITY on 50 FREQUENCY dial to give peak

indication on meter c Adjust CAL 2 LEV to give 0 on meter

2nd step a CAUTION do not change CAL 2 LEV b Switch positions

METER on CAL 1 BAND SELECTOR on CAL c Adjust CAL 1 LEV to give 0 on meter

3rd step a CAUTION do not change CAL 1 LEV or CAL 2 LEV b Switch positions

METER on ON MONITOR on M~

ATTENUATOR on CAL BAND SELECTOR on CAL SELECTIVITY on 50 shy

c Adjust FREQUENCY dial pointer to 10 on band A d Adjust CAL 2 TRIM for peak meter indication e Adjust CAL 3 control located on top of the chassis

behind the meter to give zero on the meter NOTE It is important to set the frequency dial pointer to 10

on A band in this step since adjustment of CAL 2 TRIM for peak meter indication calibrates the frequency dial

FREQUENCY CALIBRATION

Frequency recalibration is made at 1 KC each time CAL 2 TRIM control is adjusted for peak meter indication during calibration however if the frequency tuning drifts appreciably it may be desirable to recalibrate the bands t at are off and all lower frequency bands If CAL 2 TRIM gives a peak indication at either extreme of rotation (when planetary drive slips) the oscillator has drifted out of the range of the control and should be recalibrated

An accurate 1 to 160 KC oscillator or oscillator and counter will be required to recalibrate the frequency dial (main osc)

Remove the case turn on the power and allow the instrument to warm up for 30 minutes Connect the external oscillator to the INPUT jack Set its frequency as indicated in the chart below Set the CAL 2 TRIM control two turns from either limit Set the attenuator control to the level used BAND SELECTOR and frequency dial to the position indicated in the chart below Adjust the trimmer indicated in the chart to obtain a peak meter indication Do not change the position of CAL 2 TRIM until the CAL oscilmiddot shylator is checked below

AT BAND SEL FREQ DIAL ADJUST TRllIMER Level used F 90 KC F in 3019 osc

Y E 11E 40 KC i D 10 KC (or 0) D II

C II v 4 KC B 1I B 2 KC

A 1 KC (or 0) A Ii

CAL CAL 1 KC CAL (see below)

12

II

The capacitors in the local oscillator are accumulatively added to the cir shycuit as the BAND SELECTOR switch is rotated from F to CAL thus frequency calibration must be made in the order listed above Band D and A may be calibrated at zero using the local oscillator frequency For this the CampR BAL controls must be adjusted for an on scale indication Band D requires a slightly different zero balance adjustment than band A

Check the calibrate oscillator frequency as follows continuing from A band calibration Set the attenuator (AT) on CAL and BAND SELECTOR on CAL The meter should indicate a peak reading from the calibrate oscillator To check this remove the input signal set controls as given in the chart on the preshyceding page for CAL and rotate the FREQ pointer for peak meter indication The peak meter indication should occur at a frequency pointer position of 1 KC as set for band A If it does not recheck the band calibration If CAL still does not give a peak indication at 1 KC note how far off the frequency is on the dial and proceed with the next paragraph

CALIBRATE OSCILLATOR CALIBRATION

If the calibrate oscillator is no more than 25 cps off as indicated in the preceeding paragraph then pad the capacitor C69 to change the calibrate oscillator by the amount of the error If desired measure the frequency of the CAL oscillator at V7 pin 8 It should be approximately 970 cps This will vary from unit to unit Pad C69 capacitor to change the frequency

If the error is off several 100 cps the fault probably is an error in band calibration or faulty component in the local oscillator (3019)

FREQUENCY SCALE TRACKING

If the frequency tracking on anyone band is off appreciably it may be desired to readjust the appropriate components

Tracking of the DEampF bands is accomplished by changing the LC ratio of L3 to the capacitors in the tank circuit (F trimmer or C94 being the variable trimmers used for this) This is a common adjustment for all three bands normally performed on the F band Moving the last turn on the coil then compensating for the frequency change with nFn trimmer or C94 will change the tracking from 90 to 160 KC on the F band several hundred cycles When the last turn is in position cement it in place with Q dope Recalibrate frequency of D and E bands as previously given Retracking any of the above bands will require resetting and possibly retracking of the ABampC bands

Tracking of the ABampC bands is a common adjustment (normally performed on the C band) by adjusting the ratio of C92 to fiC trimmer C92 changes the band tracking as well as the oscillator frequency C trimmer primarily changes only the oscillator frequency

One method of adjusting the tracking is as follows

1 Connect an electronic counter to V2 pin 2 or 7 Set the frequency dial to 4 KC and BAND SELECTOR to HCII band Adjust trimmer for 504000hCU

cps

13

2 Rotate the frequency dial to 6 KC and note the frequency Adjust C92 to shift the oscillator frequency about 10 times the difference between the oscillator frequency and 506000 cps in the direction of needed corshyrection For example the oscillator reads 506025 cps Adjust I1C92 i to give an oscillator frequency of 250 cps less which is 505775 cps

3 Rotate the pointer to 4 KC and adjust nC1 trimmer for 504000 cps If ICi trimmer does not have enough range set it in mid-position and adshyjust the liFI trimmer This will require recalibrat ion of the iiFn band using C94 (do NOT use liF trimmer) after the llCi band tracking has been adjusted and the frequency of nB and AIi band set

4 Check frequency at 6 KC as in step 2 Repeat the adjustment of steps 2 and 3 if needed Remove the counter lead from V2 pin 2 and 7

5 Recalibrate frequency of C BampA bands as previously given Check IiC r

band tracking by measuring a 4 and 6 KC signal

IF STAGE RETUNING

In the event CAL 2 LEV amplitude cannot be turned high enough to calibrate the instrument tube replacement retuning the IF stage transformers or retuning the crystal filters will be necessary

Connect a signal of about 10 KC to the INPUT JACK Tune in the signal and adjust front panel controls for maximum meter indication with SELECTIVITY switch on 50 - Rotate the top and bottom slugs of T4 then T5 for maxshyimum meter indication Do not rotate T3 slugs

CRYSTAL FILTER RETUNING

Crystal filter transformers are Tl and T2 T3 is adjusted during the crystal filter retuning

A sweep frequency generator and dc coupled oscilloscope are required for proper crystal filter retuning These are special units and not normally available thus it is recommended that the instrument be returned to the factory if the crystal filter needs retuning

If equipment as described below is available and it is desired to retune the crystal filter v-rri te the factory for instructions

1 A sweep frequency generator with center frequency between 20 and 160 KC and sweep width adjustable from about 250 cps to 30 KC It should have a repetition rate of about 2 seconds and output amplitude of approximately 01 volt

2 A direct coupled oscilloscope with a long persistence screen

14

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

The amplifier (V8) feeds a series type demodulator (Dl D2) for monitoringlower sideband (LSB) or upper sideband (USB) signals The carrier for this demodulator is supplied by a crystal controlled oscillator ( V9) For monshyitoring amplitude modulated signals or slope detection of FM signals this oscillator is made inoperative and diode D2 removed thus the circuit opershyates as a conventional diode detector The resulting audio signal passes through the RC filter (R40 C57 C58) and amplifier ( V9 VIa) to the speaker or a headset plugged into the HEADSET jack (J3) The audio output amplitude is controlled by the potentiometer ~10N LEV (R42)

An audio signal may be amplified by inserting it in the AUDIO IN jack (if provided) just ahead of the audio amplifier ( V9 amp VIO)

A self contained calibration oscillator ( V7) is coupled to a cathode folshylower (A V7) whose output is adjusted by the potentiometer CAL 1 LEV (R55)

Plate power is furnished by a bridge type full wave selenium rectifier (SRI) A voltage regulator tube (Vll) stabilizes the plate supply to all cir shycuits except the monitor section

To prevent heater to cathode leakage and to lower 60 cps modulation (particshyularly in VI amp V2) the filaments are 50 volts DC above ground (R5-8 C9-10) 60 c~s modulation is further reduced by operating VI filament from a DC supshyply (C99middot- 101 SR5 SR6 R72)

INPUT

An input impedance of 135Q 600Q or bridging may be selected by the UNBALshyBAL switch (Sl) This switch also changes the input circuit from unbalanced to balanced on any impedance The BRIDGE input impedance is approxima~elyen 10000 ohms from 1 to 30 kc gradually falling to approximately 8000 ohms at 160 kc

An input impedance of 150 ohms instead of 135 ohms may be obtained by reshymoving resistor R3

Frequencies to be measured are connected to the INPUT connector (Jl) Both sides of the connector are insulated from the front panel thus isolating it from chassis ground during balanced measurements

ATTENUATOR

The attenuator provides 0 to 100 db of attenuation for measuring signals between -68 and +32 dbm (full scale meter indication)

The CAL position is connected to the voltage divider of the calibrate oscil shylator output for calibrating the isolation and IF amplifiers

LOCAL OSCILLATOR (3019)

The local oscillator (3019) is a hartley type using i of tube V3 The tank circuit consists of coil L3 and capacitors C36 C40 through C49C83C84 C88 amp C9l through C95 Capacitor C36 is the main tuning capacitor The even numbered capacitors C40 through C48 amp C88 are the trimmer capacitors

2

for calibrating each band Coil L3 and capacitor C92 are used to set freqshyuency tracking Capacitor C83 (CAL TRn~) is a front panel control affectshying all bands and is used for frequency calibration utilizing the self-conshytained calibrate oscillator as a standard

The local oscillator is varied from 5003 to 660 kilocycles by BAND SEL s~itch and the main tuning cap to measure frequencies of 3 to 160 kiloshycycles respectively as indicated on the frequency dial For example a Gignal of 1 kc is fed into the instrument The BAND SEL switch is set on i~ and frequency dial tuned to 10 kc The local oscillator is now oscillashyting at 501 kc and the lower sideband of demodulation is 500 kc which is the center frequency of the crystal filter

The oscillator half of V3 feeds the phase inverter half of V3 which provides 2pproximately equal potential (about 2 volts) to a plate and cathode of the demodulator tube V2 Potentiometers R25 (screwdriver control inside 3019 assy) and R24 (R MOD BAL on front panel) and capacitors C81 (screwdriver triwner inside 3019 assy) and C80 (C MOD BAL on front panel) adjusts the resistive and capacitive components in the demodulator circuit to give a minimum of oscillator potential at the cathode-plate junction of V2 (pins 1 amp 2) Balancing of the demodulator becomes critical only when the local oscillator frequency approaches the passband of the crystal filter (ie 500 kc) vfuen the oscillator is at 500 kc and the potential at V2 pin 1 amp 2 is balanced to the equivalent of -80 db at the input terminals the meter will indicate -10 As the oscillator frequency is increased the upper side of the crystal filter helps lower the local oscillator frequency potential that reaches the meter The narrow crystal filter rejection band provides at least 80 db of attenuation thus precise balance is not necessary except for measuring low frequencies The Demodulator Balance ii paragraph of 110perating Instructions 17 gives further details

The local oscillator is calibrated by feeding a known frequency into the instrument setting the frequency dial on the correct dial calibration and adjusting the band trimmer capacitor to obtain a peak meter indication

During operationcalibration at 1000 cps can be made using front panel conshytrols only For this the self-contained calibrate oscillator frequency is fed into VI the frequency dial is set at 1 kc and the meter indication peaked using CAL 2 TRn~

CALIBRATE OSCILLATOR

The calibrate oscillator is a hartley oscillator using of tube V7 It is ~oupled to a cathode follower (~ V7) whose output is adjusted by the potenshytiometer CAL 1 LEV (R55) Plate power is supplied to the calibrate oscilshylator only when the BAND SEL switch is in the CAL position thus it operates only during calibration This oscillator supplies potential for both amplishytude and frequency calibration as given in the calibration paragraph The calibrate oscillator is approximately 970 cps and calibrates the unit at 1000 cps (10 on band A) The difference in frequency compensates for capshyacity change in the BAND SEL switch when rotated from A to CAL

3

bull

SELECTIVITY

The SELECTIVITY switch is used to select one of three filters at the demodshyulator output The position marked 50 - selects a sharp crystal filter for measuring The position marked 3 KC selects a filter of appropriate width for demodulating 3 or 4 kc single sideband voice channels The position marked 10 KC selects mers determine the bathe back of the book

a n

coupling network dwidth of this position

to the IF amplifier whose The response curves

transforshyare in

D1QNITOR

The control marked MONITOR is an on-off switch for the AC power to the inshystrument and the gain control of the audio amplifier of the monitor section The USB position of the MONITOR switch connects a 50147 kc crystal to the monitor oscillator for demodulating upper sideband signals The LSB posishytion connects a 48953 kc crystal to the oscillator for demodulating lower sideband signals The AM position disconnects the plate power to the oscilshylator and disconnects diode D2 thus converting the series type demodulator to a diode detector The AM position is for monitoring amplitude or freqshyuency modulated voice channels or signals

METER SilJITCH

The t~TER switch (S5) controls the input to the meter circuit (V6 D3 amp D4 and meter) The OFF position shorts the meter input terminals to prevent pinning the needle while monitoring weak signals The ON position connects the IF amplifier output to the meter circuit for measuring and for the secshyond step of calibration The CAL 1 position connects the calibrate oscilshylator output to the meter for the first step of calibration

CALIBRATION

INTERNAL CALIBRATION amplitude and frequency Internal calibration calshyibrates the frequency dial and voltage (or DB) meter indication This is done entirely with front panel controls utilizing the self-contained calshyibrate oscillator and precision voltage divider for standards Step-byshystep procedure is given in the operating instructions

Internal calibration is accomplished in two steps The first step consists of feeding the calibrate oscillator output direct to the meter stage and adjusting the oscillator output (CAL 1 LEV) to give any desired meter indishycation (usually 0) The first part of the second step calibrates the freqshyuency It consists of rotating the FREQUENCY dial pointer to 10 on the A band and adjusting the CAL 2 TRIM control for a peak meter indication This adjustment tunes the local oscillator to the correct frequency for receivshying 1000 cps The second part of the second step calibrates the gain of the amplifiers to give proper meter indication This consists of feeding the calibrate oscillator output through the precision voltage divider (R57-R60 and attenuator CAL position) isolation amp Vl~ IF amp W4-V5) to the meter stage and adjusting the IF amp gain (CAL 2 LEV) to give the same meter inshydication set in step 1 This sets the isolation and IF amplifier gain equal to the loss in the precision voltage divider

4

BASIC CALIBRATION amplitude Basic calibration adjusts the precision voltage divider (R57-R60 and attenuator CAL position) to give the correct voltage (or DB) indication on the meter using an accurate external source as a standard This adjustment is made at the factory It can be checked and readjusted (CAL 3) if necessary as given in the maintenance section

Basic calibration consists of feeding 0 dbm into the input of the instrument and adjusting CAL 2 LEV (R37) to give zero on the meter Next the calibrate oscillator output is fed directly to the meter and adjusted by CAL 1 LEV to give 0 on the meter It is then fed through the isolation amplifier (VI) IF amp (V45 to the meter stage and CAL 3 (R58) is adjusted for 0 meter indication This adjusts the loss in the voltage divider to a value equal to the gain required in the amplifiers to give a correct meter indication

FREQUENCY BAND CALIBRATION using external frequency source The coil L3 is trimmed to set the tracking of the DE amp F bands The capacitor C92 is adjusted to set the tracking of the AB amp C bands Tracking is normally set on the F and C bands Anyone frequency on each band may be calibrated by feeding a known frequency into the instrument and adjusting trimmers C88 and C48 through C40 each for the proper band The band trimmers are progresshysively added to the tank circuit thus adjustment must be made in order from the F band to the A band Details for frequency band calibration are given in the maintenance section

5

OPERATING INSTRUCTIONS

GENERAL

Operation of the Selective Voltmeter is divided into two major functions that of measuring signals as indicated by the meter and that of monitoring carrier and audio voice bands or signals

All controls signal input audio input and output jacks and power connecshytions are on the front panel of the portable instrument Input output and power connections may be on the back of the rack mounted instrument

The power required is 48 watts 50 to 400 cps 115 volts Connection is made to the instrument with the cord furnished in the receptacle (AC) The power switch is located on the MONITOR LEVEL control where the off position is inshydicated (AC OFF)

DEMODULATOR BALANCE

Balance the demodulator as follows with the input signal disconnected (for measuring frequency below 1 kc)

a Switch positions BAND SEL on A or B FREQUENCY dial near 0 SELECTIVITY on 50 shy METER on ON MONITOR LEVEL on minimum

b Adjust MOD BAL controls C and R to obtain a mlnlmum meter reading NOTE If meter reads off scale adjust FREQUENCY dial up scale for full scale meter reading adjust C and R for preliminary balshyance (minimum meter reading) Return FREQUENCY dial to zero freqshyuency (maximum meter reading) and rebalance Repeat if necessary At final balance it should be possible to tune across 0 frequency with an on scale meter reading

c If a balance cannot be obtained within the limits (see note cl) of the CampR control on the front panel adjust the coarse CampR balance controls (see note c2) Set the CampR front panel controls in mid-range and adjust CampR coarse controls until an on scale balance is obtained Complete the balance with the front panel controls

Note cl The MOD BAL CampR controls have ball planetary drives R has a 10-turn control and C has a 4-turn control The limits of rotation are indicated when the drive slips at one extreme of rotation Note c2 Remove the unit from the case and locate the main oscillator assembly (3019) under the chassis Adjust the capacitor and potentiometer controls through the holes marked CampR

The degree of balance needed is dependent on the selectivity of the crystal filter and the frequency measured

6

L

The 50 cps crystal filter is down more than 20 db at 200 cps off and 60 db at 250 cps off thus a 0 db balance will cause negligible error when measuring a 300 cps or higher tone

A quick check is to tune in the desired signal remove the input and observe the meter reading due to carrier If it is less than an estimated -25 db tlen any reading above -10 db will be affected less than 1 db NOTE Do nnt set the meter zero on 0 volts The meter zero is used for meter trackshyi~g at -10 db

At low balance a double peak or erratic meter fluctuations may be noted These do not necessarily indicate trouble if the instrument performs satshyisfactorily when measuring a tone

The tube used as VI is critical in determining the degree of balance obtainshyable principally due to heater to cathode leakage Select a 6BH6 tube or a 66616BH6 to give best balance

INTERNAL CALIBRATION

Calibrate the instrument as follows for direct reading in dbm for the cir shycuit impedances listed Calibration for all impedances are based on 0 dbm equals 1 milliwatt of power Step CAL 2b calibrates the frequency Step CAL 2c calibrates the amplitude (meter db or voltage indication) Note Amplitude calibration is not essential for frequency calibration however frequency calibration is essential for amplitude calibration

CAL 1 a Switch positions

BAND SELECTOR to CAL ATTENUATOR to CAL METER to CAL 1 b Adjust CAL 1 LEVEL to give zero on meter DB scale for a 600Q

circuit For other circuit impedances adjust CAL 1 LEVEL to the following meter indications

(1) (3)

-6 for 150Q circuit -67 db for 130Q circuit

(2) (4)

-65 db -90 db

for 135Q circuit for 75Q circuit

CAL 2 a Switch positions

BAND SELECTOR to CAL METER to ON MONITOR to AM ATTEW0ATOR to CAL SELECTIVITY to 50 -

b Adjust FREQUENCY dial pointer to 10 on A band c d

AdjustAdjust

CAL CAL

2 TRIM to peak meter (this calibrates VAR OSC 2 LEV to give zero on meter DB scale for ALL

frequenc~)

circuit impedances (this calibrates amplitude)

This completes the calibration and the instrument is ready for use When precise measurements are needed it is recormnended that a calibration reshycheck be made during the warmup period See APPENDIX A for precautions

INPUT CIRCUIT SELECTION

The input may be unbalanced or balanced for an input impedance of 135Q 600Q or bridging as selected by the UNBAL-BAL switch The input jack on a standard unit takes a 34 spaced dual banana plug Other input conshynector types are supplied when so ordered

7

FREQUENCY SELECTION

Frequency selection is made by means of the BAND SELECTOR FREQUENCY and SELECTIVITY controls The frequency to be measured is tuned in by the large center knob and position ABC etc of the BAND SELECTOR switch

SELECTIVITY

The SELECTDIITY switch selects the crystal filter bandwidth to be used The 50 cycle position is normally used for measuring and the 3 KC and 10 KC for monitoring h~ere signals are spaced wide enough or circuit noise is low enough the 3 or 10 KC positions may be used for measuring above 3 to 6 KC or 10 to 20 KC respectively For precise measurements the internal cali shybration must be for the selectivity position to be used

AMPLITUDE MEASURElVIENT

Connect the signal to be measured to the INPUT JACK (CAUTION See overshyload paragraph) a Switch positions

BAND SELECTOR to desired band SELECTIVITY to 50 shyATTENUATOR to proper level MONITOR to AM (for precise METER to ON measurements)

b Adjust FREQUENCY dial to desired frequency and for maximum meter indication

c Add meter indication and attenuator position algebraically to obtain amplitude of signal being measured

LOW FREQUENCY ffiASUREMENTS

Measurements below about 500 cps require certain precautions The demodushylator must be balanced as given in the Demodulator Balance paragraph to prevent erroneous meter indication due to carrier leak Odd harmonics of 60 cps indicate on the meter due to internal coupling in the unit thus give a beat and cause erroneous meter indication when attempting to measure 60 and 180 cps etc The input impedance below 1 KC with the UNBAL-BAL switch on the l35Q (or below 300 cps on 600Q position) increases due to the impedance ratio of Cl to R2 amp R3 If 135Q or 600Q impedance is desired at low frequencies use the BRIDGE impedance position and an external 135Q or 600Q terminating resistor

OVERLOAD

The amplifiers of this instrument overload before the meter movement is damaged on moderate overloads--however excessive or prolonged overloads should be avoided

Amplitudes of +20 dbm or higher should not be left applied to the instrushyment for longer than a minute or two since the input circuit may heat If +20 dbm or higher amplitude is to be connected continuously a suitable pad should be connected ahead of the instrument to reduce the level below +20 dbm

LOW AMPLITUDE SIGNALS IN PRESENCE OF HIGH AMPLITUDE SIGNALS

Overloading is reduced by introducing attenuation to the input signals Therefore when measuring a low level signal when high levels are also present the more accurate reading will be made when the attenuator step is selected to give a meter reading on the lower 10 db section of the meter scale vfuen measuring circuits on which amplitudes are not approximately known it is suggested that the entire spectrum be first scanned to detershyTIline the highest amplitude signals present This will indicate the lowest level signals which may be apoundcurately measured When highest to lowest ~~els exceed 45 db some inaccuracy due to overload or intermodulation may JG 3usp~cted When measuring harmonics of a single frequency input accurshyate readings may be made 50 db or less for 2nd and 60 db or less for 3rd hi~rmonics

In any case when a low level signal is being measured if the attenuator switch is changed by 10 db and the meter reading also changes 10 db the measurement can be considered accurate

vfuen many input signals are present no simple rule can be followed as the overload point is determined by the peak envelope of the combined signals which may vary with their amplitude and phase

CARRIER MONITORING

The Selective Voltmeter may be used to monitor lower sideband (LSB) upper sideband (USB) amplitude modulated (AM) or frequency modulated (FM)signals Use the 3 kc position of SELECTIVITY switch above 3 kc only and the 10 kc position above 10 kc only

1 Upper and lower sideband monitoring a Connect the input connector to the circuit to be monitored b Switch positions

SELECTIVITY to 3 KC BAND SEL switch amp FREQUENCY DIAL to midband frequency of the

sideband MONITOR switch to LSB or USB as required MONITOR LEVEL--adjust as needed

If the voice or signal from the speaker (or headset if used in HEADSET jack) is weak turn the I1ETER switch off and the ATTENUATOR down until the desired level is reached

2 AM monitoring

To monitor AM signals feed the signal in the INPUT connector turn the seshylectivity to 3 kc or 10 kc set the MONITOR switch to AM tune the FREQshyUENCY dial to the carrier frequency and adjust the amplitude as for single sideband signals

3 FM monitoring

To monitor FM signals by slope detection feed the signal in the INPUT conshynector turn the SELECTIVITY switch to 10 kc set the MONITOR switch to AM adjust the frequency dial for best reception (one side of thA selectivity curve) and adjust the aDlplitude as for single sideband signals

9

AUDIO MONITORING (on units with AUDIO IN jack)

The audio section of the monitor circuit may be used as a amplifier if desired by inserting the signal in the AUDIO

voice frequency IN jack -The outshy

put amplitude is controlled by the MONITOR LEVEL control

10

MAINTENANCE

GENERAL

Most of the components used in the construction of RYCOM instruments are standard parts obtainable from local suppliers Precision components may be purchased from the manufacturer Special items may not be readily avail shyable from the manufacturer All replacement parts are available from RYCOM

For various reasons changes will occasionally appear in the instruction book text parts list and drawings Continued effort is being made to imshyprove circuitry and use better components During the test procedure inshydividual adjustments are made to obtain optimum operation Parts procureshyment difficulties occasiona ly require substitution of different but equivashylent parts

Normal maintenance involves replacement of tubes fuse and pilot lights

The frequency dial lights are accessible from the front by removing the knobs and black dial cover When replacing the frequency knob depress the comshypression spring washer to give sufficient torque for the desired feel in rotating the knob

To remove the instrument from the case for maintenance remove only the screws around the edge of the front panel

PARTS ORDERING

When ordering parts be sure to specify the instrument serial number as well as the instrument model number and individual part number and symbol This will insure receiving the correct replacement parts with a minimum of delay

METER TRACKING

The zero scale

adjust control is used for tracking the meter at -10 db on the

To check or reset meter tracking adjust the unit o on the meter Turn the attenuator up 10 db to Adjust meter zero screw for -10 if needed Turn readjust CAL 2 LEV for O Recheck -10

to measure a frequency read -10 on the meter attenuator dovm 10 db and

at

BASIC AMPLITUDE CALIBRATION

Tube replacement or aging may cause some error in meter indication which is not expected to be more than ~ db This can be corrected by basic recali shybration of the instrument as discussed in Calibration paragraph of the description and given in step form below

1st step a Connect an external signal of about 1500 - of 0 dbm

amplitude to the input connector (NOTE use a preshycision meter to determine the 0 dbm amplitude)

11

b Switch positions ATTENUATOR on 0 MONITOR on AM METER on ON BAND SEL on A SELECTIVITY on 50 FREQUENCY dial to give peak

indication on meter c Adjust CAL 2 LEV to give 0 on meter

2nd step a CAUTION do not change CAL 2 LEV b Switch positions

METER on CAL 1 BAND SELECTOR on CAL c Adjust CAL 1 LEV to give 0 on meter

3rd step a CAUTION do not change CAL 1 LEV or CAL 2 LEV b Switch positions

METER on ON MONITOR on M~

ATTENUATOR on CAL BAND SELECTOR on CAL SELECTIVITY on 50 shy

c Adjust FREQUENCY dial pointer to 10 on band A d Adjust CAL 2 TRIM for peak meter indication e Adjust CAL 3 control located on top of the chassis

behind the meter to give zero on the meter NOTE It is important to set the frequency dial pointer to 10

on A band in this step since adjustment of CAL 2 TRIM for peak meter indication calibrates the frequency dial

FREQUENCY CALIBRATION

Frequency recalibration is made at 1 KC each time CAL 2 TRIM control is adjusted for peak meter indication during calibration however if the frequency tuning drifts appreciably it may be desirable to recalibrate the bands t at are off and all lower frequency bands If CAL 2 TRIM gives a peak indication at either extreme of rotation (when planetary drive slips) the oscillator has drifted out of the range of the control and should be recalibrated

An accurate 1 to 160 KC oscillator or oscillator and counter will be required to recalibrate the frequency dial (main osc)

Remove the case turn on the power and allow the instrument to warm up for 30 minutes Connect the external oscillator to the INPUT jack Set its frequency as indicated in the chart below Set the CAL 2 TRIM control two turns from either limit Set the attenuator control to the level used BAND SELECTOR and frequency dial to the position indicated in the chart below Adjust the trimmer indicated in the chart to obtain a peak meter indication Do not change the position of CAL 2 TRIM until the CAL oscilmiddot shylator is checked below

AT BAND SEL FREQ DIAL ADJUST TRllIMER Level used F 90 KC F in 3019 osc

Y E 11E 40 KC i D 10 KC (or 0) D II

C II v 4 KC B 1I B 2 KC

A 1 KC (or 0) A Ii

CAL CAL 1 KC CAL (see below)

12

II

The capacitors in the local oscillator are accumulatively added to the cir shycuit as the BAND SELECTOR switch is rotated from F to CAL thus frequency calibration must be made in the order listed above Band D and A may be calibrated at zero using the local oscillator frequency For this the CampR BAL controls must be adjusted for an on scale indication Band D requires a slightly different zero balance adjustment than band A

Check the calibrate oscillator frequency as follows continuing from A band calibration Set the attenuator (AT) on CAL and BAND SELECTOR on CAL The meter should indicate a peak reading from the calibrate oscillator To check this remove the input signal set controls as given in the chart on the preshyceding page for CAL and rotate the FREQ pointer for peak meter indication The peak meter indication should occur at a frequency pointer position of 1 KC as set for band A If it does not recheck the band calibration If CAL still does not give a peak indication at 1 KC note how far off the frequency is on the dial and proceed with the next paragraph

CALIBRATE OSCILLATOR CALIBRATION

If the calibrate oscillator is no more than 25 cps off as indicated in the preceeding paragraph then pad the capacitor C69 to change the calibrate oscillator by the amount of the error If desired measure the frequency of the CAL oscillator at V7 pin 8 It should be approximately 970 cps This will vary from unit to unit Pad C69 capacitor to change the frequency

If the error is off several 100 cps the fault probably is an error in band calibration or faulty component in the local oscillator (3019)

FREQUENCY SCALE TRACKING

If the frequency tracking on anyone band is off appreciably it may be desired to readjust the appropriate components

Tracking of the DEampF bands is accomplished by changing the LC ratio of L3 to the capacitors in the tank circuit (F trimmer or C94 being the variable trimmers used for this) This is a common adjustment for all three bands normally performed on the F band Moving the last turn on the coil then compensating for the frequency change with nFn trimmer or C94 will change the tracking from 90 to 160 KC on the F band several hundred cycles When the last turn is in position cement it in place with Q dope Recalibrate frequency of D and E bands as previously given Retracking any of the above bands will require resetting and possibly retracking of the ABampC bands

Tracking of the ABampC bands is a common adjustment (normally performed on the C band) by adjusting the ratio of C92 to fiC trimmer C92 changes the band tracking as well as the oscillator frequency C trimmer primarily changes only the oscillator frequency

One method of adjusting the tracking is as follows

1 Connect an electronic counter to V2 pin 2 or 7 Set the frequency dial to 4 KC and BAND SELECTOR to HCII band Adjust trimmer for 504000hCU

cps

13

2 Rotate the frequency dial to 6 KC and note the frequency Adjust C92 to shift the oscillator frequency about 10 times the difference between the oscillator frequency and 506000 cps in the direction of needed corshyrection For example the oscillator reads 506025 cps Adjust I1C92 i to give an oscillator frequency of 250 cps less which is 505775 cps

3 Rotate the pointer to 4 KC and adjust nC1 trimmer for 504000 cps If ICi trimmer does not have enough range set it in mid-position and adshyjust the liFI trimmer This will require recalibrat ion of the iiFn band using C94 (do NOT use liF trimmer) after the llCi band tracking has been adjusted and the frequency of nB and AIi band set

4 Check frequency at 6 KC as in step 2 Repeat the adjustment of steps 2 and 3 if needed Remove the counter lead from V2 pin 2 and 7

5 Recalibrate frequency of C BampA bands as previously given Check IiC r

band tracking by measuring a 4 and 6 KC signal

IF STAGE RETUNING

In the event CAL 2 LEV amplitude cannot be turned high enough to calibrate the instrument tube replacement retuning the IF stage transformers or retuning the crystal filters will be necessary

Connect a signal of about 10 KC to the INPUT JACK Tune in the signal and adjust front panel controls for maximum meter indication with SELECTIVITY switch on 50 - Rotate the top and bottom slugs of T4 then T5 for maxshyimum meter indication Do not rotate T3 slugs

CRYSTAL FILTER RETUNING

Crystal filter transformers are Tl and T2 T3 is adjusted during the crystal filter retuning

A sweep frequency generator and dc coupled oscilloscope are required for proper crystal filter retuning These are special units and not normally available thus it is recommended that the instrument be returned to the factory if the crystal filter needs retuning

If equipment as described below is available and it is desired to retune the crystal filter v-rri te the factory for instructions

1 A sweep frequency generator with center frequency between 20 and 160 KC and sweep width adjustable from about 250 cps to 30 KC It should have a repetition rate of about 2 seconds and output amplitude of approximately 01 volt

2 A direct coupled oscilloscope with a long persistence screen

14

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

for calibrating each band Coil L3 and capacitor C92 are used to set freqshyuency tracking Capacitor C83 (CAL TRn~) is a front panel control affectshying all bands and is used for frequency calibration utilizing the self-conshytained calibrate oscillator as a standard

The local oscillator is varied from 5003 to 660 kilocycles by BAND SEL s~itch and the main tuning cap to measure frequencies of 3 to 160 kiloshycycles respectively as indicated on the frequency dial For example a Gignal of 1 kc is fed into the instrument The BAND SEL switch is set on i~ and frequency dial tuned to 10 kc The local oscillator is now oscillashyting at 501 kc and the lower sideband of demodulation is 500 kc which is the center frequency of the crystal filter

The oscillator half of V3 feeds the phase inverter half of V3 which provides 2pproximately equal potential (about 2 volts) to a plate and cathode of the demodulator tube V2 Potentiometers R25 (screwdriver control inside 3019 assy) and R24 (R MOD BAL on front panel) and capacitors C81 (screwdriver triwner inside 3019 assy) and C80 (C MOD BAL on front panel) adjusts the resistive and capacitive components in the demodulator circuit to give a minimum of oscillator potential at the cathode-plate junction of V2 (pins 1 amp 2) Balancing of the demodulator becomes critical only when the local oscillator frequency approaches the passband of the crystal filter (ie 500 kc) vfuen the oscillator is at 500 kc and the potential at V2 pin 1 amp 2 is balanced to the equivalent of -80 db at the input terminals the meter will indicate -10 As the oscillator frequency is increased the upper side of the crystal filter helps lower the local oscillator frequency potential that reaches the meter The narrow crystal filter rejection band provides at least 80 db of attenuation thus precise balance is not necessary except for measuring low frequencies The Demodulator Balance ii paragraph of 110perating Instructions 17 gives further details

The local oscillator is calibrated by feeding a known frequency into the instrument setting the frequency dial on the correct dial calibration and adjusting the band trimmer capacitor to obtain a peak meter indication

During operationcalibration at 1000 cps can be made using front panel conshytrols only For this the self-contained calibrate oscillator frequency is fed into VI the frequency dial is set at 1 kc and the meter indication peaked using CAL 2 TRn~

CALIBRATE OSCILLATOR

The calibrate oscillator is a hartley oscillator using of tube V7 It is ~oupled to a cathode follower (~ V7) whose output is adjusted by the potenshytiometer CAL 1 LEV (R55) Plate power is supplied to the calibrate oscilshylator only when the BAND SEL switch is in the CAL position thus it operates only during calibration This oscillator supplies potential for both amplishytude and frequency calibration as given in the calibration paragraph The calibrate oscillator is approximately 970 cps and calibrates the unit at 1000 cps (10 on band A) The difference in frequency compensates for capshyacity change in the BAND SEL switch when rotated from A to CAL

3

bull

SELECTIVITY

The SELECTIVITY switch is used to select one of three filters at the demodshyulator output The position marked 50 - selects a sharp crystal filter for measuring The position marked 3 KC selects a filter of appropriate width for demodulating 3 or 4 kc single sideband voice channels The position marked 10 KC selects mers determine the bathe back of the book

a n

coupling network dwidth of this position

to the IF amplifier whose The response curves

transforshyare in

D1QNITOR

The control marked MONITOR is an on-off switch for the AC power to the inshystrument and the gain control of the audio amplifier of the monitor section The USB position of the MONITOR switch connects a 50147 kc crystal to the monitor oscillator for demodulating upper sideband signals The LSB posishytion connects a 48953 kc crystal to the oscillator for demodulating lower sideband signals The AM position disconnects the plate power to the oscilshylator and disconnects diode D2 thus converting the series type demodulator to a diode detector The AM position is for monitoring amplitude or freqshyuency modulated voice channels or signals

METER SilJITCH

The t~TER switch (S5) controls the input to the meter circuit (V6 D3 amp D4 and meter) The OFF position shorts the meter input terminals to prevent pinning the needle while monitoring weak signals The ON position connects the IF amplifier output to the meter circuit for measuring and for the secshyond step of calibration The CAL 1 position connects the calibrate oscilshylator output to the meter for the first step of calibration

CALIBRATION

INTERNAL CALIBRATION amplitude and frequency Internal calibration calshyibrates the frequency dial and voltage (or DB) meter indication This is done entirely with front panel controls utilizing the self-contained calshyibrate oscillator and precision voltage divider for standards Step-byshystep procedure is given in the operating instructions

Internal calibration is accomplished in two steps The first step consists of feeding the calibrate oscillator output direct to the meter stage and adjusting the oscillator output (CAL 1 LEV) to give any desired meter indishycation (usually 0) The first part of the second step calibrates the freqshyuency It consists of rotating the FREQUENCY dial pointer to 10 on the A band and adjusting the CAL 2 TRIM control for a peak meter indication This adjustment tunes the local oscillator to the correct frequency for receivshying 1000 cps The second part of the second step calibrates the gain of the amplifiers to give proper meter indication This consists of feeding the calibrate oscillator output through the precision voltage divider (R57-R60 and attenuator CAL position) isolation amp Vl~ IF amp W4-V5) to the meter stage and adjusting the IF amp gain (CAL 2 LEV) to give the same meter inshydication set in step 1 This sets the isolation and IF amplifier gain equal to the loss in the precision voltage divider

4

BASIC CALIBRATION amplitude Basic calibration adjusts the precision voltage divider (R57-R60 and attenuator CAL position) to give the correct voltage (or DB) indication on the meter using an accurate external source as a standard This adjustment is made at the factory It can be checked and readjusted (CAL 3) if necessary as given in the maintenance section

Basic calibration consists of feeding 0 dbm into the input of the instrument and adjusting CAL 2 LEV (R37) to give zero on the meter Next the calibrate oscillator output is fed directly to the meter and adjusted by CAL 1 LEV to give 0 on the meter It is then fed through the isolation amplifier (VI) IF amp (V45 to the meter stage and CAL 3 (R58) is adjusted for 0 meter indication This adjusts the loss in the voltage divider to a value equal to the gain required in the amplifiers to give a correct meter indication

FREQUENCY BAND CALIBRATION using external frequency source The coil L3 is trimmed to set the tracking of the DE amp F bands The capacitor C92 is adjusted to set the tracking of the AB amp C bands Tracking is normally set on the F and C bands Anyone frequency on each band may be calibrated by feeding a known frequency into the instrument and adjusting trimmers C88 and C48 through C40 each for the proper band The band trimmers are progresshysively added to the tank circuit thus adjustment must be made in order from the F band to the A band Details for frequency band calibration are given in the maintenance section

5

OPERATING INSTRUCTIONS

GENERAL

Operation of the Selective Voltmeter is divided into two major functions that of measuring signals as indicated by the meter and that of monitoring carrier and audio voice bands or signals

All controls signal input audio input and output jacks and power connecshytions are on the front panel of the portable instrument Input output and power connections may be on the back of the rack mounted instrument

The power required is 48 watts 50 to 400 cps 115 volts Connection is made to the instrument with the cord furnished in the receptacle (AC) The power switch is located on the MONITOR LEVEL control where the off position is inshydicated (AC OFF)

DEMODULATOR BALANCE

Balance the demodulator as follows with the input signal disconnected (for measuring frequency below 1 kc)

a Switch positions BAND SEL on A or B FREQUENCY dial near 0 SELECTIVITY on 50 shy METER on ON MONITOR LEVEL on minimum

b Adjust MOD BAL controls C and R to obtain a mlnlmum meter reading NOTE If meter reads off scale adjust FREQUENCY dial up scale for full scale meter reading adjust C and R for preliminary balshyance (minimum meter reading) Return FREQUENCY dial to zero freqshyuency (maximum meter reading) and rebalance Repeat if necessary At final balance it should be possible to tune across 0 frequency with an on scale meter reading

c If a balance cannot be obtained within the limits (see note cl) of the CampR control on the front panel adjust the coarse CampR balance controls (see note c2) Set the CampR front panel controls in mid-range and adjust CampR coarse controls until an on scale balance is obtained Complete the balance with the front panel controls

Note cl The MOD BAL CampR controls have ball planetary drives R has a 10-turn control and C has a 4-turn control The limits of rotation are indicated when the drive slips at one extreme of rotation Note c2 Remove the unit from the case and locate the main oscillator assembly (3019) under the chassis Adjust the capacitor and potentiometer controls through the holes marked CampR

The degree of balance needed is dependent on the selectivity of the crystal filter and the frequency measured

6

L

The 50 cps crystal filter is down more than 20 db at 200 cps off and 60 db at 250 cps off thus a 0 db balance will cause negligible error when measuring a 300 cps or higher tone

A quick check is to tune in the desired signal remove the input and observe the meter reading due to carrier If it is less than an estimated -25 db tlen any reading above -10 db will be affected less than 1 db NOTE Do nnt set the meter zero on 0 volts The meter zero is used for meter trackshyi~g at -10 db

At low balance a double peak or erratic meter fluctuations may be noted These do not necessarily indicate trouble if the instrument performs satshyisfactorily when measuring a tone

The tube used as VI is critical in determining the degree of balance obtainshyable principally due to heater to cathode leakage Select a 6BH6 tube or a 66616BH6 to give best balance

INTERNAL CALIBRATION

Calibrate the instrument as follows for direct reading in dbm for the cir shycuit impedances listed Calibration for all impedances are based on 0 dbm equals 1 milliwatt of power Step CAL 2b calibrates the frequency Step CAL 2c calibrates the amplitude (meter db or voltage indication) Note Amplitude calibration is not essential for frequency calibration however frequency calibration is essential for amplitude calibration

CAL 1 a Switch positions

BAND SELECTOR to CAL ATTENUATOR to CAL METER to CAL 1 b Adjust CAL 1 LEVEL to give zero on meter DB scale for a 600Q

circuit For other circuit impedances adjust CAL 1 LEVEL to the following meter indications

(1) (3)

-6 for 150Q circuit -67 db for 130Q circuit

(2) (4)

-65 db -90 db

for 135Q circuit for 75Q circuit

CAL 2 a Switch positions

BAND SELECTOR to CAL METER to ON MONITOR to AM ATTEW0ATOR to CAL SELECTIVITY to 50 -

b Adjust FREQUENCY dial pointer to 10 on A band c d

AdjustAdjust

CAL CAL

2 TRIM to peak meter (this calibrates VAR OSC 2 LEV to give zero on meter DB scale for ALL

frequenc~)

circuit impedances (this calibrates amplitude)

This completes the calibration and the instrument is ready for use When precise measurements are needed it is recormnended that a calibration reshycheck be made during the warmup period See APPENDIX A for precautions

INPUT CIRCUIT SELECTION

The input may be unbalanced or balanced for an input impedance of 135Q 600Q or bridging as selected by the UNBAL-BAL switch The input jack on a standard unit takes a 34 spaced dual banana plug Other input conshynector types are supplied when so ordered

7

FREQUENCY SELECTION

Frequency selection is made by means of the BAND SELECTOR FREQUENCY and SELECTIVITY controls The frequency to be measured is tuned in by the large center knob and position ABC etc of the BAND SELECTOR switch

SELECTIVITY

The SELECTDIITY switch selects the crystal filter bandwidth to be used The 50 cycle position is normally used for measuring and the 3 KC and 10 KC for monitoring h~ere signals are spaced wide enough or circuit noise is low enough the 3 or 10 KC positions may be used for measuring above 3 to 6 KC or 10 to 20 KC respectively For precise measurements the internal cali shybration must be for the selectivity position to be used

AMPLITUDE MEASURElVIENT

Connect the signal to be measured to the INPUT JACK (CAUTION See overshyload paragraph) a Switch positions

BAND SELECTOR to desired band SELECTIVITY to 50 shyATTENUATOR to proper level MONITOR to AM (for precise METER to ON measurements)

b Adjust FREQUENCY dial to desired frequency and for maximum meter indication

c Add meter indication and attenuator position algebraically to obtain amplitude of signal being measured

LOW FREQUENCY ffiASUREMENTS

Measurements below about 500 cps require certain precautions The demodushylator must be balanced as given in the Demodulator Balance paragraph to prevent erroneous meter indication due to carrier leak Odd harmonics of 60 cps indicate on the meter due to internal coupling in the unit thus give a beat and cause erroneous meter indication when attempting to measure 60 and 180 cps etc The input impedance below 1 KC with the UNBAL-BAL switch on the l35Q (or below 300 cps on 600Q position) increases due to the impedance ratio of Cl to R2 amp R3 If 135Q or 600Q impedance is desired at low frequencies use the BRIDGE impedance position and an external 135Q or 600Q terminating resistor

OVERLOAD

The amplifiers of this instrument overload before the meter movement is damaged on moderate overloads--however excessive or prolonged overloads should be avoided

Amplitudes of +20 dbm or higher should not be left applied to the instrushyment for longer than a minute or two since the input circuit may heat If +20 dbm or higher amplitude is to be connected continuously a suitable pad should be connected ahead of the instrument to reduce the level below +20 dbm

LOW AMPLITUDE SIGNALS IN PRESENCE OF HIGH AMPLITUDE SIGNALS

Overloading is reduced by introducing attenuation to the input signals Therefore when measuring a low level signal when high levels are also present the more accurate reading will be made when the attenuator step is selected to give a meter reading on the lower 10 db section of the meter scale vfuen measuring circuits on which amplitudes are not approximately known it is suggested that the entire spectrum be first scanned to detershyTIline the highest amplitude signals present This will indicate the lowest level signals which may be apoundcurately measured When highest to lowest ~~els exceed 45 db some inaccuracy due to overload or intermodulation may JG 3usp~cted When measuring harmonics of a single frequency input accurshyate readings may be made 50 db or less for 2nd and 60 db or less for 3rd hi~rmonics

In any case when a low level signal is being measured if the attenuator switch is changed by 10 db and the meter reading also changes 10 db the measurement can be considered accurate

vfuen many input signals are present no simple rule can be followed as the overload point is determined by the peak envelope of the combined signals which may vary with their amplitude and phase

CARRIER MONITORING

The Selective Voltmeter may be used to monitor lower sideband (LSB) upper sideband (USB) amplitude modulated (AM) or frequency modulated (FM)signals Use the 3 kc position of SELECTIVITY switch above 3 kc only and the 10 kc position above 10 kc only

1 Upper and lower sideband monitoring a Connect the input connector to the circuit to be monitored b Switch positions

SELECTIVITY to 3 KC BAND SEL switch amp FREQUENCY DIAL to midband frequency of the

sideband MONITOR switch to LSB or USB as required MONITOR LEVEL--adjust as needed

If the voice or signal from the speaker (or headset if used in HEADSET jack) is weak turn the I1ETER switch off and the ATTENUATOR down until the desired level is reached

2 AM monitoring

To monitor AM signals feed the signal in the INPUT connector turn the seshylectivity to 3 kc or 10 kc set the MONITOR switch to AM tune the FREQshyUENCY dial to the carrier frequency and adjust the amplitude as for single sideband signals

3 FM monitoring

To monitor FM signals by slope detection feed the signal in the INPUT conshynector turn the SELECTIVITY switch to 10 kc set the MONITOR switch to AM adjust the frequency dial for best reception (one side of thA selectivity curve) and adjust the aDlplitude as for single sideband signals

9

AUDIO MONITORING (on units with AUDIO IN jack)

The audio section of the monitor circuit may be used as a amplifier if desired by inserting the signal in the AUDIO

voice frequency IN jack -The outshy

put amplitude is controlled by the MONITOR LEVEL control

10

MAINTENANCE

GENERAL

Most of the components used in the construction of RYCOM instruments are standard parts obtainable from local suppliers Precision components may be purchased from the manufacturer Special items may not be readily avail shyable from the manufacturer All replacement parts are available from RYCOM

For various reasons changes will occasionally appear in the instruction book text parts list and drawings Continued effort is being made to imshyprove circuitry and use better components During the test procedure inshydividual adjustments are made to obtain optimum operation Parts procureshyment difficulties occasiona ly require substitution of different but equivashylent parts

Normal maintenance involves replacement of tubes fuse and pilot lights

The frequency dial lights are accessible from the front by removing the knobs and black dial cover When replacing the frequency knob depress the comshypression spring washer to give sufficient torque for the desired feel in rotating the knob

To remove the instrument from the case for maintenance remove only the screws around the edge of the front panel

PARTS ORDERING

When ordering parts be sure to specify the instrument serial number as well as the instrument model number and individual part number and symbol This will insure receiving the correct replacement parts with a minimum of delay

METER TRACKING

The zero scale

adjust control is used for tracking the meter at -10 db on the

To check or reset meter tracking adjust the unit o on the meter Turn the attenuator up 10 db to Adjust meter zero screw for -10 if needed Turn readjust CAL 2 LEV for O Recheck -10

to measure a frequency read -10 on the meter attenuator dovm 10 db and

at

BASIC AMPLITUDE CALIBRATION

Tube replacement or aging may cause some error in meter indication which is not expected to be more than ~ db This can be corrected by basic recali shybration of the instrument as discussed in Calibration paragraph of the description and given in step form below

1st step a Connect an external signal of about 1500 - of 0 dbm

amplitude to the input connector (NOTE use a preshycision meter to determine the 0 dbm amplitude)

11

b Switch positions ATTENUATOR on 0 MONITOR on AM METER on ON BAND SEL on A SELECTIVITY on 50 FREQUENCY dial to give peak

indication on meter c Adjust CAL 2 LEV to give 0 on meter

2nd step a CAUTION do not change CAL 2 LEV b Switch positions

METER on CAL 1 BAND SELECTOR on CAL c Adjust CAL 1 LEV to give 0 on meter

3rd step a CAUTION do not change CAL 1 LEV or CAL 2 LEV b Switch positions

METER on ON MONITOR on M~

ATTENUATOR on CAL BAND SELECTOR on CAL SELECTIVITY on 50 shy

c Adjust FREQUENCY dial pointer to 10 on band A d Adjust CAL 2 TRIM for peak meter indication e Adjust CAL 3 control located on top of the chassis

behind the meter to give zero on the meter NOTE It is important to set the frequency dial pointer to 10

on A band in this step since adjustment of CAL 2 TRIM for peak meter indication calibrates the frequency dial

FREQUENCY CALIBRATION

Frequency recalibration is made at 1 KC each time CAL 2 TRIM control is adjusted for peak meter indication during calibration however if the frequency tuning drifts appreciably it may be desirable to recalibrate the bands t at are off and all lower frequency bands If CAL 2 TRIM gives a peak indication at either extreme of rotation (when planetary drive slips) the oscillator has drifted out of the range of the control and should be recalibrated

An accurate 1 to 160 KC oscillator or oscillator and counter will be required to recalibrate the frequency dial (main osc)

Remove the case turn on the power and allow the instrument to warm up for 30 minutes Connect the external oscillator to the INPUT jack Set its frequency as indicated in the chart below Set the CAL 2 TRIM control two turns from either limit Set the attenuator control to the level used BAND SELECTOR and frequency dial to the position indicated in the chart below Adjust the trimmer indicated in the chart to obtain a peak meter indication Do not change the position of CAL 2 TRIM until the CAL oscilmiddot shylator is checked below

AT BAND SEL FREQ DIAL ADJUST TRllIMER Level used F 90 KC F in 3019 osc

Y E 11E 40 KC i D 10 KC (or 0) D II

C II v 4 KC B 1I B 2 KC

A 1 KC (or 0) A Ii

CAL CAL 1 KC CAL (see below)

12

II

The capacitors in the local oscillator are accumulatively added to the cir shycuit as the BAND SELECTOR switch is rotated from F to CAL thus frequency calibration must be made in the order listed above Band D and A may be calibrated at zero using the local oscillator frequency For this the CampR BAL controls must be adjusted for an on scale indication Band D requires a slightly different zero balance adjustment than band A

Check the calibrate oscillator frequency as follows continuing from A band calibration Set the attenuator (AT) on CAL and BAND SELECTOR on CAL The meter should indicate a peak reading from the calibrate oscillator To check this remove the input signal set controls as given in the chart on the preshyceding page for CAL and rotate the FREQ pointer for peak meter indication The peak meter indication should occur at a frequency pointer position of 1 KC as set for band A If it does not recheck the band calibration If CAL still does not give a peak indication at 1 KC note how far off the frequency is on the dial and proceed with the next paragraph

CALIBRATE OSCILLATOR CALIBRATION

If the calibrate oscillator is no more than 25 cps off as indicated in the preceeding paragraph then pad the capacitor C69 to change the calibrate oscillator by the amount of the error If desired measure the frequency of the CAL oscillator at V7 pin 8 It should be approximately 970 cps This will vary from unit to unit Pad C69 capacitor to change the frequency

If the error is off several 100 cps the fault probably is an error in band calibration or faulty component in the local oscillator (3019)

FREQUENCY SCALE TRACKING

If the frequency tracking on anyone band is off appreciably it may be desired to readjust the appropriate components

Tracking of the DEampF bands is accomplished by changing the LC ratio of L3 to the capacitors in the tank circuit (F trimmer or C94 being the variable trimmers used for this) This is a common adjustment for all three bands normally performed on the F band Moving the last turn on the coil then compensating for the frequency change with nFn trimmer or C94 will change the tracking from 90 to 160 KC on the F band several hundred cycles When the last turn is in position cement it in place with Q dope Recalibrate frequency of D and E bands as previously given Retracking any of the above bands will require resetting and possibly retracking of the ABampC bands

Tracking of the ABampC bands is a common adjustment (normally performed on the C band) by adjusting the ratio of C92 to fiC trimmer C92 changes the band tracking as well as the oscillator frequency C trimmer primarily changes only the oscillator frequency

One method of adjusting the tracking is as follows

1 Connect an electronic counter to V2 pin 2 or 7 Set the frequency dial to 4 KC and BAND SELECTOR to HCII band Adjust trimmer for 504000hCU

cps

13

2 Rotate the frequency dial to 6 KC and note the frequency Adjust C92 to shift the oscillator frequency about 10 times the difference between the oscillator frequency and 506000 cps in the direction of needed corshyrection For example the oscillator reads 506025 cps Adjust I1C92 i to give an oscillator frequency of 250 cps less which is 505775 cps

3 Rotate the pointer to 4 KC and adjust nC1 trimmer for 504000 cps If ICi trimmer does not have enough range set it in mid-position and adshyjust the liFI trimmer This will require recalibrat ion of the iiFn band using C94 (do NOT use liF trimmer) after the llCi band tracking has been adjusted and the frequency of nB and AIi band set

4 Check frequency at 6 KC as in step 2 Repeat the adjustment of steps 2 and 3 if needed Remove the counter lead from V2 pin 2 and 7

5 Recalibrate frequency of C BampA bands as previously given Check IiC r

band tracking by measuring a 4 and 6 KC signal

IF STAGE RETUNING

In the event CAL 2 LEV amplitude cannot be turned high enough to calibrate the instrument tube replacement retuning the IF stage transformers or retuning the crystal filters will be necessary

Connect a signal of about 10 KC to the INPUT JACK Tune in the signal and adjust front panel controls for maximum meter indication with SELECTIVITY switch on 50 - Rotate the top and bottom slugs of T4 then T5 for maxshyimum meter indication Do not rotate T3 slugs

CRYSTAL FILTER RETUNING

Crystal filter transformers are Tl and T2 T3 is adjusted during the crystal filter retuning

A sweep frequency generator and dc coupled oscilloscope are required for proper crystal filter retuning These are special units and not normally available thus it is recommended that the instrument be returned to the factory if the crystal filter needs retuning

If equipment as described below is available and it is desired to retune the crystal filter v-rri te the factory for instructions

1 A sweep frequency generator with center frequency between 20 and 160 KC and sweep width adjustable from about 250 cps to 30 KC It should have a repetition rate of about 2 seconds and output amplitude of approximately 01 volt

2 A direct coupled oscilloscope with a long persistence screen

14

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

SELECTIVITY

The SELECTIVITY switch is used to select one of three filters at the demodshyulator output The position marked 50 - selects a sharp crystal filter for measuring The position marked 3 KC selects a filter of appropriate width for demodulating 3 or 4 kc single sideband voice channels The position marked 10 KC selects mers determine the bathe back of the book

a n

coupling network dwidth of this position

to the IF amplifier whose The response curves

transforshyare in

D1QNITOR

The control marked MONITOR is an on-off switch for the AC power to the inshystrument and the gain control of the audio amplifier of the monitor section The USB position of the MONITOR switch connects a 50147 kc crystal to the monitor oscillator for demodulating upper sideband signals The LSB posishytion connects a 48953 kc crystal to the oscillator for demodulating lower sideband signals The AM position disconnects the plate power to the oscilshylator and disconnects diode D2 thus converting the series type demodulator to a diode detector The AM position is for monitoring amplitude or freqshyuency modulated voice channels or signals

METER SilJITCH

The t~TER switch (S5) controls the input to the meter circuit (V6 D3 amp D4 and meter) The OFF position shorts the meter input terminals to prevent pinning the needle while monitoring weak signals The ON position connects the IF amplifier output to the meter circuit for measuring and for the secshyond step of calibration The CAL 1 position connects the calibrate oscilshylator output to the meter for the first step of calibration

CALIBRATION

INTERNAL CALIBRATION amplitude and frequency Internal calibration calshyibrates the frequency dial and voltage (or DB) meter indication This is done entirely with front panel controls utilizing the self-contained calshyibrate oscillator and precision voltage divider for standards Step-byshystep procedure is given in the operating instructions

Internal calibration is accomplished in two steps The first step consists of feeding the calibrate oscillator output direct to the meter stage and adjusting the oscillator output (CAL 1 LEV) to give any desired meter indishycation (usually 0) The first part of the second step calibrates the freqshyuency It consists of rotating the FREQUENCY dial pointer to 10 on the A band and adjusting the CAL 2 TRIM control for a peak meter indication This adjustment tunes the local oscillator to the correct frequency for receivshying 1000 cps The second part of the second step calibrates the gain of the amplifiers to give proper meter indication This consists of feeding the calibrate oscillator output through the precision voltage divider (R57-R60 and attenuator CAL position) isolation amp Vl~ IF amp W4-V5) to the meter stage and adjusting the IF amp gain (CAL 2 LEV) to give the same meter inshydication set in step 1 This sets the isolation and IF amplifier gain equal to the loss in the precision voltage divider

4

BASIC CALIBRATION amplitude Basic calibration adjusts the precision voltage divider (R57-R60 and attenuator CAL position) to give the correct voltage (or DB) indication on the meter using an accurate external source as a standard This adjustment is made at the factory It can be checked and readjusted (CAL 3) if necessary as given in the maintenance section

Basic calibration consists of feeding 0 dbm into the input of the instrument and adjusting CAL 2 LEV (R37) to give zero on the meter Next the calibrate oscillator output is fed directly to the meter and adjusted by CAL 1 LEV to give 0 on the meter It is then fed through the isolation amplifier (VI) IF amp (V45 to the meter stage and CAL 3 (R58) is adjusted for 0 meter indication This adjusts the loss in the voltage divider to a value equal to the gain required in the amplifiers to give a correct meter indication

FREQUENCY BAND CALIBRATION using external frequency source The coil L3 is trimmed to set the tracking of the DE amp F bands The capacitor C92 is adjusted to set the tracking of the AB amp C bands Tracking is normally set on the F and C bands Anyone frequency on each band may be calibrated by feeding a known frequency into the instrument and adjusting trimmers C88 and C48 through C40 each for the proper band The band trimmers are progresshysively added to the tank circuit thus adjustment must be made in order from the F band to the A band Details for frequency band calibration are given in the maintenance section

5

OPERATING INSTRUCTIONS

GENERAL

Operation of the Selective Voltmeter is divided into two major functions that of measuring signals as indicated by the meter and that of monitoring carrier and audio voice bands or signals

All controls signal input audio input and output jacks and power connecshytions are on the front panel of the portable instrument Input output and power connections may be on the back of the rack mounted instrument

The power required is 48 watts 50 to 400 cps 115 volts Connection is made to the instrument with the cord furnished in the receptacle (AC) The power switch is located on the MONITOR LEVEL control where the off position is inshydicated (AC OFF)

DEMODULATOR BALANCE

Balance the demodulator as follows with the input signal disconnected (for measuring frequency below 1 kc)

a Switch positions BAND SEL on A or B FREQUENCY dial near 0 SELECTIVITY on 50 shy METER on ON MONITOR LEVEL on minimum

b Adjust MOD BAL controls C and R to obtain a mlnlmum meter reading NOTE If meter reads off scale adjust FREQUENCY dial up scale for full scale meter reading adjust C and R for preliminary balshyance (minimum meter reading) Return FREQUENCY dial to zero freqshyuency (maximum meter reading) and rebalance Repeat if necessary At final balance it should be possible to tune across 0 frequency with an on scale meter reading

c If a balance cannot be obtained within the limits (see note cl) of the CampR control on the front panel adjust the coarse CampR balance controls (see note c2) Set the CampR front panel controls in mid-range and adjust CampR coarse controls until an on scale balance is obtained Complete the balance with the front panel controls

Note cl The MOD BAL CampR controls have ball planetary drives R has a 10-turn control and C has a 4-turn control The limits of rotation are indicated when the drive slips at one extreme of rotation Note c2 Remove the unit from the case and locate the main oscillator assembly (3019) under the chassis Adjust the capacitor and potentiometer controls through the holes marked CampR

The degree of balance needed is dependent on the selectivity of the crystal filter and the frequency measured

6

L

The 50 cps crystal filter is down more than 20 db at 200 cps off and 60 db at 250 cps off thus a 0 db balance will cause negligible error when measuring a 300 cps or higher tone

A quick check is to tune in the desired signal remove the input and observe the meter reading due to carrier If it is less than an estimated -25 db tlen any reading above -10 db will be affected less than 1 db NOTE Do nnt set the meter zero on 0 volts The meter zero is used for meter trackshyi~g at -10 db

At low balance a double peak or erratic meter fluctuations may be noted These do not necessarily indicate trouble if the instrument performs satshyisfactorily when measuring a tone

The tube used as VI is critical in determining the degree of balance obtainshyable principally due to heater to cathode leakage Select a 6BH6 tube or a 66616BH6 to give best balance

INTERNAL CALIBRATION

Calibrate the instrument as follows for direct reading in dbm for the cir shycuit impedances listed Calibration for all impedances are based on 0 dbm equals 1 milliwatt of power Step CAL 2b calibrates the frequency Step CAL 2c calibrates the amplitude (meter db or voltage indication) Note Amplitude calibration is not essential for frequency calibration however frequency calibration is essential for amplitude calibration

CAL 1 a Switch positions

BAND SELECTOR to CAL ATTENUATOR to CAL METER to CAL 1 b Adjust CAL 1 LEVEL to give zero on meter DB scale for a 600Q

circuit For other circuit impedances adjust CAL 1 LEVEL to the following meter indications

(1) (3)

-6 for 150Q circuit -67 db for 130Q circuit

(2) (4)

-65 db -90 db

for 135Q circuit for 75Q circuit

CAL 2 a Switch positions

BAND SELECTOR to CAL METER to ON MONITOR to AM ATTEW0ATOR to CAL SELECTIVITY to 50 -

b Adjust FREQUENCY dial pointer to 10 on A band c d

AdjustAdjust

CAL CAL

2 TRIM to peak meter (this calibrates VAR OSC 2 LEV to give zero on meter DB scale for ALL

frequenc~)

circuit impedances (this calibrates amplitude)

This completes the calibration and the instrument is ready for use When precise measurements are needed it is recormnended that a calibration reshycheck be made during the warmup period See APPENDIX A for precautions

INPUT CIRCUIT SELECTION

The input may be unbalanced or balanced for an input impedance of 135Q 600Q or bridging as selected by the UNBAL-BAL switch The input jack on a standard unit takes a 34 spaced dual banana plug Other input conshynector types are supplied when so ordered

7

FREQUENCY SELECTION

Frequency selection is made by means of the BAND SELECTOR FREQUENCY and SELECTIVITY controls The frequency to be measured is tuned in by the large center knob and position ABC etc of the BAND SELECTOR switch

SELECTIVITY

The SELECTDIITY switch selects the crystal filter bandwidth to be used The 50 cycle position is normally used for measuring and the 3 KC and 10 KC for monitoring h~ere signals are spaced wide enough or circuit noise is low enough the 3 or 10 KC positions may be used for measuring above 3 to 6 KC or 10 to 20 KC respectively For precise measurements the internal cali shybration must be for the selectivity position to be used

AMPLITUDE MEASURElVIENT

Connect the signal to be measured to the INPUT JACK (CAUTION See overshyload paragraph) a Switch positions

BAND SELECTOR to desired band SELECTIVITY to 50 shyATTENUATOR to proper level MONITOR to AM (for precise METER to ON measurements)

b Adjust FREQUENCY dial to desired frequency and for maximum meter indication

c Add meter indication and attenuator position algebraically to obtain amplitude of signal being measured

LOW FREQUENCY ffiASUREMENTS

Measurements below about 500 cps require certain precautions The demodushylator must be balanced as given in the Demodulator Balance paragraph to prevent erroneous meter indication due to carrier leak Odd harmonics of 60 cps indicate on the meter due to internal coupling in the unit thus give a beat and cause erroneous meter indication when attempting to measure 60 and 180 cps etc The input impedance below 1 KC with the UNBAL-BAL switch on the l35Q (or below 300 cps on 600Q position) increases due to the impedance ratio of Cl to R2 amp R3 If 135Q or 600Q impedance is desired at low frequencies use the BRIDGE impedance position and an external 135Q or 600Q terminating resistor

OVERLOAD

The amplifiers of this instrument overload before the meter movement is damaged on moderate overloads--however excessive or prolonged overloads should be avoided

Amplitudes of +20 dbm or higher should not be left applied to the instrushyment for longer than a minute or two since the input circuit may heat If +20 dbm or higher amplitude is to be connected continuously a suitable pad should be connected ahead of the instrument to reduce the level below +20 dbm

LOW AMPLITUDE SIGNALS IN PRESENCE OF HIGH AMPLITUDE SIGNALS

Overloading is reduced by introducing attenuation to the input signals Therefore when measuring a low level signal when high levels are also present the more accurate reading will be made when the attenuator step is selected to give a meter reading on the lower 10 db section of the meter scale vfuen measuring circuits on which amplitudes are not approximately known it is suggested that the entire spectrum be first scanned to detershyTIline the highest amplitude signals present This will indicate the lowest level signals which may be apoundcurately measured When highest to lowest ~~els exceed 45 db some inaccuracy due to overload or intermodulation may JG 3usp~cted When measuring harmonics of a single frequency input accurshyate readings may be made 50 db or less for 2nd and 60 db or less for 3rd hi~rmonics

In any case when a low level signal is being measured if the attenuator switch is changed by 10 db and the meter reading also changes 10 db the measurement can be considered accurate

vfuen many input signals are present no simple rule can be followed as the overload point is determined by the peak envelope of the combined signals which may vary with their amplitude and phase

CARRIER MONITORING

The Selective Voltmeter may be used to monitor lower sideband (LSB) upper sideband (USB) amplitude modulated (AM) or frequency modulated (FM)signals Use the 3 kc position of SELECTIVITY switch above 3 kc only and the 10 kc position above 10 kc only

1 Upper and lower sideband monitoring a Connect the input connector to the circuit to be monitored b Switch positions

SELECTIVITY to 3 KC BAND SEL switch amp FREQUENCY DIAL to midband frequency of the

sideband MONITOR switch to LSB or USB as required MONITOR LEVEL--adjust as needed

If the voice or signal from the speaker (or headset if used in HEADSET jack) is weak turn the I1ETER switch off and the ATTENUATOR down until the desired level is reached

2 AM monitoring

To monitor AM signals feed the signal in the INPUT connector turn the seshylectivity to 3 kc or 10 kc set the MONITOR switch to AM tune the FREQshyUENCY dial to the carrier frequency and adjust the amplitude as for single sideband signals

3 FM monitoring

To monitor FM signals by slope detection feed the signal in the INPUT conshynector turn the SELECTIVITY switch to 10 kc set the MONITOR switch to AM adjust the frequency dial for best reception (one side of thA selectivity curve) and adjust the aDlplitude as for single sideband signals

9

AUDIO MONITORING (on units with AUDIO IN jack)

The audio section of the monitor circuit may be used as a amplifier if desired by inserting the signal in the AUDIO

voice frequency IN jack -The outshy

put amplitude is controlled by the MONITOR LEVEL control

10

MAINTENANCE

GENERAL

Most of the components used in the construction of RYCOM instruments are standard parts obtainable from local suppliers Precision components may be purchased from the manufacturer Special items may not be readily avail shyable from the manufacturer All replacement parts are available from RYCOM

For various reasons changes will occasionally appear in the instruction book text parts list and drawings Continued effort is being made to imshyprove circuitry and use better components During the test procedure inshydividual adjustments are made to obtain optimum operation Parts procureshyment difficulties occasiona ly require substitution of different but equivashylent parts

Normal maintenance involves replacement of tubes fuse and pilot lights

The frequency dial lights are accessible from the front by removing the knobs and black dial cover When replacing the frequency knob depress the comshypression spring washer to give sufficient torque for the desired feel in rotating the knob

To remove the instrument from the case for maintenance remove only the screws around the edge of the front panel

PARTS ORDERING

When ordering parts be sure to specify the instrument serial number as well as the instrument model number and individual part number and symbol This will insure receiving the correct replacement parts with a minimum of delay

METER TRACKING

The zero scale

adjust control is used for tracking the meter at -10 db on the

To check or reset meter tracking adjust the unit o on the meter Turn the attenuator up 10 db to Adjust meter zero screw for -10 if needed Turn readjust CAL 2 LEV for O Recheck -10

to measure a frequency read -10 on the meter attenuator dovm 10 db and

at

BASIC AMPLITUDE CALIBRATION

Tube replacement or aging may cause some error in meter indication which is not expected to be more than ~ db This can be corrected by basic recali shybration of the instrument as discussed in Calibration paragraph of the description and given in step form below

1st step a Connect an external signal of about 1500 - of 0 dbm

amplitude to the input connector (NOTE use a preshycision meter to determine the 0 dbm amplitude)

11

b Switch positions ATTENUATOR on 0 MONITOR on AM METER on ON BAND SEL on A SELECTIVITY on 50 FREQUENCY dial to give peak

indication on meter c Adjust CAL 2 LEV to give 0 on meter

2nd step a CAUTION do not change CAL 2 LEV b Switch positions

METER on CAL 1 BAND SELECTOR on CAL c Adjust CAL 1 LEV to give 0 on meter

3rd step a CAUTION do not change CAL 1 LEV or CAL 2 LEV b Switch positions

METER on ON MONITOR on M~

ATTENUATOR on CAL BAND SELECTOR on CAL SELECTIVITY on 50 shy

c Adjust FREQUENCY dial pointer to 10 on band A d Adjust CAL 2 TRIM for peak meter indication e Adjust CAL 3 control located on top of the chassis

behind the meter to give zero on the meter NOTE It is important to set the frequency dial pointer to 10

on A band in this step since adjustment of CAL 2 TRIM for peak meter indication calibrates the frequency dial

FREQUENCY CALIBRATION

Frequency recalibration is made at 1 KC each time CAL 2 TRIM control is adjusted for peak meter indication during calibration however if the frequency tuning drifts appreciably it may be desirable to recalibrate the bands t at are off and all lower frequency bands If CAL 2 TRIM gives a peak indication at either extreme of rotation (when planetary drive slips) the oscillator has drifted out of the range of the control and should be recalibrated

An accurate 1 to 160 KC oscillator or oscillator and counter will be required to recalibrate the frequency dial (main osc)

Remove the case turn on the power and allow the instrument to warm up for 30 minutes Connect the external oscillator to the INPUT jack Set its frequency as indicated in the chart below Set the CAL 2 TRIM control two turns from either limit Set the attenuator control to the level used BAND SELECTOR and frequency dial to the position indicated in the chart below Adjust the trimmer indicated in the chart to obtain a peak meter indication Do not change the position of CAL 2 TRIM until the CAL oscilmiddot shylator is checked below

AT BAND SEL FREQ DIAL ADJUST TRllIMER Level used F 90 KC F in 3019 osc

Y E 11E 40 KC i D 10 KC (or 0) D II

C II v 4 KC B 1I B 2 KC

A 1 KC (or 0) A Ii

CAL CAL 1 KC CAL (see below)

12

II

The capacitors in the local oscillator are accumulatively added to the cir shycuit as the BAND SELECTOR switch is rotated from F to CAL thus frequency calibration must be made in the order listed above Band D and A may be calibrated at zero using the local oscillator frequency For this the CampR BAL controls must be adjusted for an on scale indication Band D requires a slightly different zero balance adjustment than band A

Check the calibrate oscillator frequency as follows continuing from A band calibration Set the attenuator (AT) on CAL and BAND SELECTOR on CAL The meter should indicate a peak reading from the calibrate oscillator To check this remove the input signal set controls as given in the chart on the preshyceding page for CAL and rotate the FREQ pointer for peak meter indication The peak meter indication should occur at a frequency pointer position of 1 KC as set for band A If it does not recheck the band calibration If CAL still does not give a peak indication at 1 KC note how far off the frequency is on the dial and proceed with the next paragraph

CALIBRATE OSCILLATOR CALIBRATION

If the calibrate oscillator is no more than 25 cps off as indicated in the preceeding paragraph then pad the capacitor C69 to change the calibrate oscillator by the amount of the error If desired measure the frequency of the CAL oscillator at V7 pin 8 It should be approximately 970 cps This will vary from unit to unit Pad C69 capacitor to change the frequency

If the error is off several 100 cps the fault probably is an error in band calibration or faulty component in the local oscillator (3019)

FREQUENCY SCALE TRACKING

If the frequency tracking on anyone band is off appreciably it may be desired to readjust the appropriate components

Tracking of the DEampF bands is accomplished by changing the LC ratio of L3 to the capacitors in the tank circuit (F trimmer or C94 being the variable trimmers used for this) This is a common adjustment for all three bands normally performed on the F band Moving the last turn on the coil then compensating for the frequency change with nFn trimmer or C94 will change the tracking from 90 to 160 KC on the F band several hundred cycles When the last turn is in position cement it in place with Q dope Recalibrate frequency of D and E bands as previously given Retracking any of the above bands will require resetting and possibly retracking of the ABampC bands

Tracking of the ABampC bands is a common adjustment (normally performed on the C band) by adjusting the ratio of C92 to fiC trimmer C92 changes the band tracking as well as the oscillator frequency C trimmer primarily changes only the oscillator frequency

One method of adjusting the tracking is as follows

1 Connect an electronic counter to V2 pin 2 or 7 Set the frequency dial to 4 KC and BAND SELECTOR to HCII band Adjust trimmer for 504000hCU

cps

13

2 Rotate the frequency dial to 6 KC and note the frequency Adjust C92 to shift the oscillator frequency about 10 times the difference between the oscillator frequency and 506000 cps in the direction of needed corshyrection For example the oscillator reads 506025 cps Adjust I1C92 i to give an oscillator frequency of 250 cps less which is 505775 cps

3 Rotate the pointer to 4 KC and adjust nC1 trimmer for 504000 cps If ICi trimmer does not have enough range set it in mid-position and adshyjust the liFI trimmer This will require recalibrat ion of the iiFn band using C94 (do NOT use liF trimmer) after the llCi band tracking has been adjusted and the frequency of nB and AIi band set

4 Check frequency at 6 KC as in step 2 Repeat the adjustment of steps 2 and 3 if needed Remove the counter lead from V2 pin 2 and 7

5 Recalibrate frequency of C BampA bands as previously given Check IiC r

band tracking by measuring a 4 and 6 KC signal

IF STAGE RETUNING

In the event CAL 2 LEV amplitude cannot be turned high enough to calibrate the instrument tube replacement retuning the IF stage transformers or retuning the crystal filters will be necessary

Connect a signal of about 10 KC to the INPUT JACK Tune in the signal and adjust front panel controls for maximum meter indication with SELECTIVITY switch on 50 - Rotate the top and bottom slugs of T4 then T5 for maxshyimum meter indication Do not rotate T3 slugs

CRYSTAL FILTER RETUNING

Crystal filter transformers are Tl and T2 T3 is adjusted during the crystal filter retuning

A sweep frequency generator and dc coupled oscilloscope are required for proper crystal filter retuning These are special units and not normally available thus it is recommended that the instrument be returned to the factory if the crystal filter needs retuning

If equipment as described below is available and it is desired to retune the crystal filter v-rri te the factory for instructions

1 A sweep frequency generator with center frequency between 20 and 160 KC and sweep width adjustable from about 250 cps to 30 KC It should have a repetition rate of about 2 seconds and output amplitude of approximately 01 volt

2 A direct coupled oscilloscope with a long persistence screen

14

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

BASIC CALIBRATION amplitude Basic calibration adjusts the precision voltage divider (R57-R60 and attenuator CAL position) to give the correct voltage (or DB) indication on the meter using an accurate external source as a standard This adjustment is made at the factory It can be checked and readjusted (CAL 3) if necessary as given in the maintenance section

Basic calibration consists of feeding 0 dbm into the input of the instrument and adjusting CAL 2 LEV (R37) to give zero on the meter Next the calibrate oscillator output is fed directly to the meter and adjusted by CAL 1 LEV to give 0 on the meter It is then fed through the isolation amplifier (VI) IF amp (V45 to the meter stage and CAL 3 (R58) is adjusted for 0 meter indication This adjusts the loss in the voltage divider to a value equal to the gain required in the amplifiers to give a correct meter indication

FREQUENCY BAND CALIBRATION using external frequency source The coil L3 is trimmed to set the tracking of the DE amp F bands The capacitor C92 is adjusted to set the tracking of the AB amp C bands Tracking is normally set on the F and C bands Anyone frequency on each band may be calibrated by feeding a known frequency into the instrument and adjusting trimmers C88 and C48 through C40 each for the proper band The band trimmers are progresshysively added to the tank circuit thus adjustment must be made in order from the F band to the A band Details for frequency band calibration are given in the maintenance section

5

OPERATING INSTRUCTIONS

GENERAL

Operation of the Selective Voltmeter is divided into two major functions that of measuring signals as indicated by the meter and that of monitoring carrier and audio voice bands or signals

All controls signal input audio input and output jacks and power connecshytions are on the front panel of the portable instrument Input output and power connections may be on the back of the rack mounted instrument

The power required is 48 watts 50 to 400 cps 115 volts Connection is made to the instrument with the cord furnished in the receptacle (AC) The power switch is located on the MONITOR LEVEL control where the off position is inshydicated (AC OFF)

DEMODULATOR BALANCE

Balance the demodulator as follows with the input signal disconnected (for measuring frequency below 1 kc)

a Switch positions BAND SEL on A or B FREQUENCY dial near 0 SELECTIVITY on 50 shy METER on ON MONITOR LEVEL on minimum

b Adjust MOD BAL controls C and R to obtain a mlnlmum meter reading NOTE If meter reads off scale adjust FREQUENCY dial up scale for full scale meter reading adjust C and R for preliminary balshyance (minimum meter reading) Return FREQUENCY dial to zero freqshyuency (maximum meter reading) and rebalance Repeat if necessary At final balance it should be possible to tune across 0 frequency with an on scale meter reading

c If a balance cannot be obtained within the limits (see note cl) of the CampR control on the front panel adjust the coarse CampR balance controls (see note c2) Set the CampR front panel controls in mid-range and adjust CampR coarse controls until an on scale balance is obtained Complete the balance with the front panel controls

Note cl The MOD BAL CampR controls have ball planetary drives R has a 10-turn control and C has a 4-turn control The limits of rotation are indicated when the drive slips at one extreme of rotation Note c2 Remove the unit from the case and locate the main oscillator assembly (3019) under the chassis Adjust the capacitor and potentiometer controls through the holes marked CampR

The degree of balance needed is dependent on the selectivity of the crystal filter and the frequency measured

6

L

The 50 cps crystal filter is down more than 20 db at 200 cps off and 60 db at 250 cps off thus a 0 db balance will cause negligible error when measuring a 300 cps or higher tone

A quick check is to tune in the desired signal remove the input and observe the meter reading due to carrier If it is less than an estimated -25 db tlen any reading above -10 db will be affected less than 1 db NOTE Do nnt set the meter zero on 0 volts The meter zero is used for meter trackshyi~g at -10 db

At low balance a double peak or erratic meter fluctuations may be noted These do not necessarily indicate trouble if the instrument performs satshyisfactorily when measuring a tone

The tube used as VI is critical in determining the degree of balance obtainshyable principally due to heater to cathode leakage Select a 6BH6 tube or a 66616BH6 to give best balance

INTERNAL CALIBRATION

Calibrate the instrument as follows for direct reading in dbm for the cir shycuit impedances listed Calibration for all impedances are based on 0 dbm equals 1 milliwatt of power Step CAL 2b calibrates the frequency Step CAL 2c calibrates the amplitude (meter db or voltage indication) Note Amplitude calibration is not essential for frequency calibration however frequency calibration is essential for amplitude calibration

CAL 1 a Switch positions

BAND SELECTOR to CAL ATTENUATOR to CAL METER to CAL 1 b Adjust CAL 1 LEVEL to give zero on meter DB scale for a 600Q

circuit For other circuit impedances adjust CAL 1 LEVEL to the following meter indications

(1) (3)

-6 for 150Q circuit -67 db for 130Q circuit

(2) (4)

-65 db -90 db

for 135Q circuit for 75Q circuit

CAL 2 a Switch positions

BAND SELECTOR to CAL METER to ON MONITOR to AM ATTEW0ATOR to CAL SELECTIVITY to 50 -

b Adjust FREQUENCY dial pointer to 10 on A band c d

AdjustAdjust

CAL CAL

2 TRIM to peak meter (this calibrates VAR OSC 2 LEV to give zero on meter DB scale for ALL

frequenc~)

circuit impedances (this calibrates amplitude)

This completes the calibration and the instrument is ready for use When precise measurements are needed it is recormnended that a calibration reshycheck be made during the warmup period See APPENDIX A for precautions

INPUT CIRCUIT SELECTION

The input may be unbalanced or balanced for an input impedance of 135Q 600Q or bridging as selected by the UNBAL-BAL switch The input jack on a standard unit takes a 34 spaced dual banana plug Other input conshynector types are supplied when so ordered

7

FREQUENCY SELECTION

Frequency selection is made by means of the BAND SELECTOR FREQUENCY and SELECTIVITY controls The frequency to be measured is tuned in by the large center knob and position ABC etc of the BAND SELECTOR switch

SELECTIVITY

The SELECTDIITY switch selects the crystal filter bandwidth to be used The 50 cycle position is normally used for measuring and the 3 KC and 10 KC for monitoring h~ere signals are spaced wide enough or circuit noise is low enough the 3 or 10 KC positions may be used for measuring above 3 to 6 KC or 10 to 20 KC respectively For precise measurements the internal cali shybration must be for the selectivity position to be used

AMPLITUDE MEASURElVIENT

Connect the signal to be measured to the INPUT JACK (CAUTION See overshyload paragraph) a Switch positions

BAND SELECTOR to desired band SELECTIVITY to 50 shyATTENUATOR to proper level MONITOR to AM (for precise METER to ON measurements)

b Adjust FREQUENCY dial to desired frequency and for maximum meter indication

c Add meter indication and attenuator position algebraically to obtain amplitude of signal being measured

LOW FREQUENCY ffiASUREMENTS

Measurements below about 500 cps require certain precautions The demodushylator must be balanced as given in the Demodulator Balance paragraph to prevent erroneous meter indication due to carrier leak Odd harmonics of 60 cps indicate on the meter due to internal coupling in the unit thus give a beat and cause erroneous meter indication when attempting to measure 60 and 180 cps etc The input impedance below 1 KC with the UNBAL-BAL switch on the l35Q (or below 300 cps on 600Q position) increases due to the impedance ratio of Cl to R2 amp R3 If 135Q or 600Q impedance is desired at low frequencies use the BRIDGE impedance position and an external 135Q or 600Q terminating resistor

OVERLOAD

The amplifiers of this instrument overload before the meter movement is damaged on moderate overloads--however excessive or prolonged overloads should be avoided

Amplitudes of +20 dbm or higher should not be left applied to the instrushyment for longer than a minute or two since the input circuit may heat If +20 dbm or higher amplitude is to be connected continuously a suitable pad should be connected ahead of the instrument to reduce the level below +20 dbm

LOW AMPLITUDE SIGNALS IN PRESENCE OF HIGH AMPLITUDE SIGNALS

Overloading is reduced by introducing attenuation to the input signals Therefore when measuring a low level signal when high levels are also present the more accurate reading will be made when the attenuator step is selected to give a meter reading on the lower 10 db section of the meter scale vfuen measuring circuits on which amplitudes are not approximately known it is suggested that the entire spectrum be first scanned to detershyTIline the highest amplitude signals present This will indicate the lowest level signals which may be apoundcurately measured When highest to lowest ~~els exceed 45 db some inaccuracy due to overload or intermodulation may JG 3usp~cted When measuring harmonics of a single frequency input accurshyate readings may be made 50 db or less for 2nd and 60 db or less for 3rd hi~rmonics

In any case when a low level signal is being measured if the attenuator switch is changed by 10 db and the meter reading also changes 10 db the measurement can be considered accurate

vfuen many input signals are present no simple rule can be followed as the overload point is determined by the peak envelope of the combined signals which may vary with their amplitude and phase

CARRIER MONITORING

The Selective Voltmeter may be used to monitor lower sideband (LSB) upper sideband (USB) amplitude modulated (AM) or frequency modulated (FM)signals Use the 3 kc position of SELECTIVITY switch above 3 kc only and the 10 kc position above 10 kc only

1 Upper and lower sideband monitoring a Connect the input connector to the circuit to be monitored b Switch positions

SELECTIVITY to 3 KC BAND SEL switch amp FREQUENCY DIAL to midband frequency of the

sideband MONITOR switch to LSB or USB as required MONITOR LEVEL--adjust as needed

If the voice or signal from the speaker (or headset if used in HEADSET jack) is weak turn the I1ETER switch off and the ATTENUATOR down until the desired level is reached

2 AM monitoring

To monitor AM signals feed the signal in the INPUT connector turn the seshylectivity to 3 kc or 10 kc set the MONITOR switch to AM tune the FREQshyUENCY dial to the carrier frequency and adjust the amplitude as for single sideband signals

3 FM monitoring

To monitor FM signals by slope detection feed the signal in the INPUT conshynector turn the SELECTIVITY switch to 10 kc set the MONITOR switch to AM adjust the frequency dial for best reception (one side of thA selectivity curve) and adjust the aDlplitude as for single sideband signals

9

AUDIO MONITORING (on units with AUDIO IN jack)

The audio section of the monitor circuit may be used as a amplifier if desired by inserting the signal in the AUDIO

voice frequency IN jack -The outshy

put amplitude is controlled by the MONITOR LEVEL control

10

MAINTENANCE

GENERAL

Most of the components used in the construction of RYCOM instruments are standard parts obtainable from local suppliers Precision components may be purchased from the manufacturer Special items may not be readily avail shyable from the manufacturer All replacement parts are available from RYCOM

For various reasons changes will occasionally appear in the instruction book text parts list and drawings Continued effort is being made to imshyprove circuitry and use better components During the test procedure inshydividual adjustments are made to obtain optimum operation Parts procureshyment difficulties occasiona ly require substitution of different but equivashylent parts

Normal maintenance involves replacement of tubes fuse and pilot lights

The frequency dial lights are accessible from the front by removing the knobs and black dial cover When replacing the frequency knob depress the comshypression spring washer to give sufficient torque for the desired feel in rotating the knob

To remove the instrument from the case for maintenance remove only the screws around the edge of the front panel

PARTS ORDERING

When ordering parts be sure to specify the instrument serial number as well as the instrument model number and individual part number and symbol This will insure receiving the correct replacement parts with a minimum of delay

METER TRACKING

The zero scale

adjust control is used for tracking the meter at -10 db on the

To check or reset meter tracking adjust the unit o on the meter Turn the attenuator up 10 db to Adjust meter zero screw for -10 if needed Turn readjust CAL 2 LEV for O Recheck -10

to measure a frequency read -10 on the meter attenuator dovm 10 db and

at

BASIC AMPLITUDE CALIBRATION

Tube replacement or aging may cause some error in meter indication which is not expected to be more than ~ db This can be corrected by basic recali shybration of the instrument as discussed in Calibration paragraph of the description and given in step form below

1st step a Connect an external signal of about 1500 - of 0 dbm

amplitude to the input connector (NOTE use a preshycision meter to determine the 0 dbm amplitude)

11

b Switch positions ATTENUATOR on 0 MONITOR on AM METER on ON BAND SEL on A SELECTIVITY on 50 FREQUENCY dial to give peak

indication on meter c Adjust CAL 2 LEV to give 0 on meter

2nd step a CAUTION do not change CAL 2 LEV b Switch positions

METER on CAL 1 BAND SELECTOR on CAL c Adjust CAL 1 LEV to give 0 on meter

3rd step a CAUTION do not change CAL 1 LEV or CAL 2 LEV b Switch positions

METER on ON MONITOR on M~

ATTENUATOR on CAL BAND SELECTOR on CAL SELECTIVITY on 50 shy

c Adjust FREQUENCY dial pointer to 10 on band A d Adjust CAL 2 TRIM for peak meter indication e Adjust CAL 3 control located on top of the chassis

behind the meter to give zero on the meter NOTE It is important to set the frequency dial pointer to 10

on A band in this step since adjustment of CAL 2 TRIM for peak meter indication calibrates the frequency dial

FREQUENCY CALIBRATION

Frequency recalibration is made at 1 KC each time CAL 2 TRIM control is adjusted for peak meter indication during calibration however if the frequency tuning drifts appreciably it may be desirable to recalibrate the bands t at are off and all lower frequency bands If CAL 2 TRIM gives a peak indication at either extreme of rotation (when planetary drive slips) the oscillator has drifted out of the range of the control and should be recalibrated

An accurate 1 to 160 KC oscillator or oscillator and counter will be required to recalibrate the frequency dial (main osc)

Remove the case turn on the power and allow the instrument to warm up for 30 minutes Connect the external oscillator to the INPUT jack Set its frequency as indicated in the chart below Set the CAL 2 TRIM control two turns from either limit Set the attenuator control to the level used BAND SELECTOR and frequency dial to the position indicated in the chart below Adjust the trimmer indicated in the chart to obtain a peak meter indication Do not change the position of CAL 2 TRIM until the CAL oscilmiddot shylator is checked below

AT BAND SEL FREQ DIAL ADJUST TRllIMER Level used F 90 KC F in 3019 osc

Y E 11E 40 KC i D 10 KC (or 0) D II

C II v 4 KC B 1I B 2 KC

A 1 KC (or 0) A Ii

CAL CAL 1 KC CAL (see below)

12

II

The capacitors in the local oscillator are accumulatively added to the cir shycuit as the BAND SELECTOR switch is rotated from F to CAL thus frequency calibration must be made in the order listed above Band D and A may be calibrated at zero using the local oscillator frequency For this the CampR BAL controls must be adjusted for an on scale indication Band D requires a slightly different zero balance adjustment than band A

Check the calibrate oscillator frequency as follows continuing from A band calibration Set the attenuator (AT) on CAL and BAND SELECTOR on CAL The meter should indicate a peak reading from the calibrate oscillator To check this remove the input signal set controls as given in the chart on the preshyceding page for CAL and rotate the FREQ pointer for peak meter indication The peak meter indication should occur at a frequency pointer position of 1 KC as set for band A If it does not recheck the band calibration If CAL still does not give a peak indication at 1 KC note how far off the frequency is on the dial and proceed with the next paragraph

CALIBRATE OSCILLATOR CALIBRATION

If the calibrate oscillator is no more than 25 cps off as indicated in the preceeding paragraph then pad the capacitor C69 to change the calibrate oscillator by the amount of the error If desired measure the frequency of the CAL oscillator at V7 pin 8 It should be approximately 970 cps This will vary from unit to unit Pad C69 capacitor to change the frequency

If the error is off several 100 cps the fault probably is an error in band calibration or faulty component in the local oscillator (3019)

FREQUENCY SCALE TRACKING

If the frequency tracking on anyone band is off appreciably it may be desired to readjust the appropriate components

Tracking of the DEampF bands is accomplished by changing the LC ratio of L3 to the capacitors in the tank circuit (F trimmer or C94 being the variable trimmers used for this) This is a common adjustment for all three bands normally performed on the F band Moving the last turn on the coil then compensating for the frequency change with nFn trimmer or C94 will change the tracking from 90 to 160 KC on the F band several hundred cycles When the last turn is in position cement it in place with Q dope Recalibrate frequency of D and E bands as previously given Retracking any of the above bands will require resetting and possibly retracking of the ABampC bands

Tracking of the ABampC bands is a common adjustment (normally performed on the C band) by adjusting the ratio of C92 to fiC trimmer C92 changes the band tracking as well as the oscillator frequency C trimmer primarily changes only the oscillator frequency

One method of adjusting the tracking is as follows

1 Connect an electronic counter to V2 pin 2 or 7 Set the frequency dial to 4 KC and BAND SELECTOR to HCII band Adjust trimmer for 504000hCU

cps

13

2 Rotate the frequency dial to 6 KC and note the frequency Adjust C92 to shift the oscillator frequency about 10 times the difference between the oscillator frequency and 506000 cps in the direction of needed corshyrection For example the oscillator reads 506025 cps Adjust I1C92 i to give an oscillator frequency of 250 cps less which is 505775 cps

3 Rotate the pointer to 4 KC and adjust nC1 trimmer for 504000 cps If ICi trimmer does not have enough range set it in mid-position and adshyjust the liFI trimmer This will require recalibrat ion of the iiFn band using C94 (do NOT use liF trimmer) after the llCi band tracking has been adjusted and the frequency of nB and AIi band set

4 Check frequency at 6 KC as in step 2 Repeat the adjustment of steps 2 and 3 if needed Remove the counter lead from V2 pin 2 and 7

5 Recalibrate frequency of C BampA bands as previously given Check IiC r

band tracking by measuring a 4 and 6 KC signal

IF STAGE RETUNING

In the event CAL 2 LEV amplitude cannot be turned high enough to calibrate the instrument tube replacement retuning the IF stage transformers or retuning the crystal filters will be necessary

Connect a signal of about 10 KC to the INPUT JACK Tune in the signal and adjust front panel controls for maximum meter indication with SELECTIVITY switch on 50 - Rotate the top and bottom slugs of T4 then T5 for maxshyimum meter indication Do not rotate T3 slugs

CRYSTAL FILTER RETUNING

Crystal filter transformers are Tl and T2 T3 is adjusted during the crystal filter retuning

A sweep frequency generator and dc coupled oscilloscope are required for proper crystal filter retuning These are special units and not normally available thus it is recommended that the instrument be returned to the factory if the crystal filter needs retuning

If equipment as described below is available and it is desired to retune the crystal filter v-rri te the factory for instructions

1 A sweep frequency generator with center frequency between 20 and 160 KC and sweep width adjustable from about 250 cps to 30 KC It should have a repetition rate of about 2 seconds and output amplitude of approximately 01 volt

2 A direct coupled oscilloscope with a long persistence screen

14

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

OPERATING INSTRUCTIONS

GENERAL

Operation of the Selective Voltmeter is divided into two major functions that of measuring signals as indicated by the meter and that of monitoring carrier and audio voice bands or signals

All controls signal input audio input and output jacks and power connecshytions are on the front panel of the portable instrument Input output and power connections may be on the back of the rack mounted instrument

The power required is 48 watts 50 to 400 cps 115 volts Connection is made to the instrument with the cord furnished in the receptacle (AC) The power switch is located on the MONITOR LEVEL control where the off position is inshydicated (AC OFF)

DEMODULATOR BALANCE

Balance the demodulator as follows with the input signal disconnected (for measuring frequency below 1 kc)

a Switch positions BAND SEL on A or B FREQUENCY dial near 0 SELECTIVITY on 50 shy METER on ON MONITOR LEVEL on minimum

b Adjust MOD BAL controls C and R to obtain a mlnlmum meter reading NOTE If meter reads off scale adjust FREQUENCY dial up scale for full scale meter reading adjust C and R for preliminary balshyance (minimum meter reading) Return FREQUENCY dial to zero freqshyuency (maximum meter reading) and rebalance Repeat if necessary At final balance it should be possible to tune across 0 frequency with an on scale meter reading

c If a balance cannot be obtained within the limits (see note cl) of the CampR control on the front panel adjust the coarse CampR balance controls (see note c2) Set the CampR front panel controls in mid-range and adjust CampR coarse controls until an on scale balance is obtained Complete the balance with the front panel controls

Note cl The MOD BAL CampR controls have ball planetary drives R has a 10-turn control and C has a 4-turn control The limits of rotation are indicated when the drive slips at one extreme of rotation Note c2 Remove the unit from the case and locate the main oscillator assembly (3019) under the chassis Adjust the capacitor and potentiometer controls through the holes marked CampR

The degree of balance needed is dependent on the selectivity of the crystal filter and the frequency measured

6

L

The 50 cps crystal filter is down more than 20 db at 200 cps off and 60 db at 250 cps off thus a 0 db balance will cause negligible error when measuring a 300 cps or higher tone

A quick check is to tune in the desired signal remove the input and observe the meter reading due to carrier If it is less than an estimated -25 db tlen any reading above -10 db will be affected less than 1 db NOTE Do nnt set the meter zero on 0 volts The meter zero is used for meter trackshyi~g at -10 db

At low balance a double peak or erratic meter fluctuations may be noted These do not necessarily indicate trouble if the instrument performs satshyisfactorily when measuring a tone

The tube used as VI is critical in determining the degree of balance obtainshyable principally due to heater to cathode leakage Select a 6BH6 tube or a 66616BH6 to give best balance

INTERNAL CALIBRATION

Calibrate the instrument as follows for direct reading in dbm for the cir shycuit impedances listed Calibration for all impedances are based on 0 dbm equals 1 milliwatt of power Step CAL 2b calibrates the frequency Step CAL 2c calibrates the amplitude (meter db or voltage indication) Note Amplitude calibration is not essential for frequency calibration however frequency calibration is essential for amplitude calibration

CAL 1 a Switch positions

BAND SELECTOR to CAL ATTENUATOR to CAL METER to CAL 1 b Adjust CAL 1 LEVEL to give zero on meter DB scale for a 600Q

circuit For other circuit impedances adjust CAL 1 LEVEL to the following meter indications

(1) (3)

-6 for 150Q circuit -67 db for 130Q circuit

(2) (4)

-65 db -90 db

for 135Q circuit for 75Q circuit

CAL 2 a Switch positions

BAND SELECTOR to CAL METER to ON MONITOR to AM ATTEW0ATOR to CAL SELECTIVITY to 50 -

b Adjust FREQUENCY dial pointer to 10 on A band c d

AdjustAdjust

CAL CAL

2 TRIM to peak meter (this calibrates VAR OSC 2 LEV to give zero on meter DB scale for ALL

frequenc~)

circuit impedances (this calibrates amplitude)

This completes the calibration and the instrument is ready for use When precise measurements are needed it is recormnended that a calibration reshycheck be made during the warmup period See APPENDIX A for precautions

INPUT CIRCUIT SELECTION

The input may be unbalanced or balanced for an input impedance of 135Q 600Q or bridging as selected by the UNBAL-BAL switch The input jack on a standard unit takes a 34 spaced dual banana plug Other input conshynector types are supplied when so ordered

7

FREQUENCY SELECTION

Frequency selection is made by means of the BAND SELECTOR FREQUENCY and SELECTIVITY controls The frequency to be measured is tuned in by the large center knob and position ABC etc of the BAND SELECTOR switch

SELECTIVITY

The SELECTDIITY switch selects the crystal filter bandwidth to be used The 50 cycle position is normally used for measuring and the 3 KC and 10 KC for monitoring h~ere signals are spaced wide enough or circuit noise is low enough the 3 or 10 KC positions may be used for measuring above 3 to 6 KC or 10 to 20 KC respectively For precise measurements the internal cali shybration must be for the selectivity position to be used

AMPLITUDE MEASURElVIENT

Connect the signal to be measured to the INPUT JACK (CAUTION See overshyload paragraph) a Switch positions

BAND SELECTOR to desired band SELECTIVITY to 50 shyATTENUATOR to proper level MONITOR to AM (for precise METER to ON measurements)

b Adjust FREQUENCY dial to desired frequency and for maximum meter indication

c Add meter indication and attenuator position algebraically to obtain amplitude of signal being measured

LOW FREQUENCY ffiASUREMENTS

Measurements below about 500 cps require certain precautions The demodushylator must be balanced as given in the Demodulator Balance paragraph to prevent erroneous meter indication due to carrier leak Odd harmonics of 60 cps indicate on the meter due to internal coupling in the unit thus give a beat and cause erroneous meter indication when attempting to measure 60 and 180 cps etc The input impedance below 1 KC with the UNBAL-BAL switch on the l35Q (or below 300 cps on 600Q position) increases due to the impedance ratio of Cl to R2 amp R3 If 135Q or 600Q impedance is desired at low frequencies use the BRIDGE impedance position and an external 135Q or 600Q terminating resistor

OVERLOAD

The amplifiers of this instrument overload before the meter movement is damaged on moderate overloads--however excessive or prolonged overloads should be avoided

Amplitudes of +20 dbm or higher should not be left applied to the instrushyment for longer than a minute or two since the input circuit may heat If +20 dbm or higher amplitude is to be connected continuously a suitable pad should be connected ahead of the instrument to reduce the level below +20 dbm

LOW AMPLITUDE SIGNALS IN PRESENCE OF HIGH AMPLITUDE SIGNALS

Overloading is reduced by introducing attenuation to the input signals Therefore when measuring a low level signal when high levels are also present the more accurate reading will be made when the attenuator step is selected to give a meter reading on the lower 10 db section of the meter scale vfuen measuring circuits on which amplitudes are not approximately known it is suggested that the entire spectrum be first scanned to detershyTIline the highest amplitude signals present This will indicate the lowest level signals which may be apoundcurately measured When highest to lowest ~~els exceed 45 db some inaccuracy due to overload or intermodulation may JG 3usp~cted When measuring harmonics of a single frequency input accurshyate readings may be made 50 db or less for 2nd and 60 db or less for 3rd hi~rmonics

In any case when a low level signal is being measured if the attenuator switch is changed by 10 db and the meter reading also changes 10 db the measurement can be considered accurate

vfuen many input signals are present no simple rule can be followed as the overload point is determined by the peak envelope of the combined signals which may vary with their amplitude and phase

CARRIER MONITORING

The Selective Voltmeter may be used to monitor lower sideband (LSB) upper sideband (USB) amplitude modulated (AM) or frequency modulated (FM)signals Use the 3 kc position of SELECTIVITY switch above 3 kc only and the 10 kc position above 10 kc only

1 Upper and lower sideband monitoring a Connect the input connector to the circuit to be monitored b Switch positions

SELECTIVITY to 3 KC BAND SEL switch amp FREQUENCY DIAL to midband frequency of the

sideband MONITOR switch to LSB or USB as required MONITOR LEVEL--adjust as needed

If the voice or signal from the speaker (or headset if used in HEADSET jack) is weak turn the I1ETER switch off and the ATTENUATOR down until the desired level is reached

2 AM monitoring

To monitor AM signals feed the signal in the INPUT connector turn the seshylectivity to 3 kc or 10 kc set the MONITOR switch to AM tune the FREQshyUENCY dial to the carrier frequency and adjust the amplitude as for single sideband signals

3 FM monitoring

To monitor FM signals by slope detection feed the signal in the INPUT conshynector turn the SELECTIVITY switch to 10 kc set the MONITOR switch to AM adjust the frequency dial for best reception (one side of thA selectivity curve) and adjust the aDlplitude as for single sideband signals

9

AUDIO MONITORING (on units with AUDIO IN jack)

The audio section of the monitor circuit may be used as a amplifier if desired by inserting the signal in the AUDIO

voice frequency IN jack -The outshy

put amplitude is controlled by the MONITOR LEVEL control

10

MAINTENANCE

GENERAL

Most of the components used in the construction of RYCOM instruments are standard parts obtainable from local suppliers Precision components may be purchased from the manufacturer Special items may not be readily avail shyable from the manufacturer All replacement parts are available from RYCOM

For various reasons changes will occasionally appear in the instruction book text parts list and drawings Continued effort is being made to imshyprove circuitry and use better components During the test procedure inshydividual adjustments are made to obtain optimum operation Parts procureshyment difficulties occasiona ly require substitution of different but equivashylent parts

Normal maintenance involves replacement of tubes fuse and pilot lights

The frequency dial lights are accessible from the front by removing the knobs and black dial cover When replacing the frequency knob depress the comshypression spring washer to give sufficient torque for the desired feel in rotating the knob

To remove the instrument from the case for maintenance remove only the screws around the edge of the front panel

PARTS ORDERING

When ordering parts be sure to specify the instrument serial number as well as the instrument model number and individual part number and symbol This will insure receiving the correct replacement parts with a minimum of delay

METER TRACKING

The zero scale

adjust control is used for tracking the meter at -10 db on the

To check or reset meter tracking adjust the unit o on the meter Turn the attenuator up 10 db to Adjust meter zero screw for -10 if needed Turn readjust CAL 2 LEV for O Recheck -10

to measure a frequency read -10 on the meter attenuator dovm 10 db and

at

BASIC AMPLITUDE CALIBRATION

Tube replacement or aging may cause some error in meter indication which is not expected to be more than ~ db This can be corrected by basic recali shybration of the instrument as discussed in Calibration paragraph of the description and given in step form below

1st step a Connect an external signal of about 1500 - of 0 dbm

amplitude to the input connector (NOTE use a preshycision meter to determine the 0 dbm amplitude)

11

b Switch positions ATTENUATOR on 0 MONITOR on AM METER on ON BAND SEL on A SELECTIVITY on 50 FREQUENCY dial to give peak

indication on meter c Adjust CAL 2 LEV to give 0 on meter

2nd step a CAUTION do not change CAL 2 LEV b Switch positions

METER on CAL 1 BAND SELECTOR on CAL c Adjust CAL 1 LEV to give 0 on meter

3rd step a CAUTION do not change CAL 1 LEV or CAL 2 LEV b Switch positions

METER on ON MONITOR on M~

ATTENUATOR on CAL BAND SELECTOR on CAL SELECTIVITY on 50 shy

c Adjust FREQUENCY dial pointer to 10 on band A d Adjust CAL 2 TRIM for peak meter indication e Adjust CAL 3 control located on top of the chassis

behind the meter to give zero on the meter NOTE It is important to set the frequency dial pointer to 10

on A band in this step since adjustment of CAL 2 TRIM for peak meter indication calibrates the frequency dial

FREQUENCY CALIBRATION

Frequency recalibration is made at 1 KC each time CAL 2 TRIM control is adjusted for peak meter indication during calibration however if the frequency tuning drifts appreciably it may be desirable to recalibrate the bands t at are off and all lower frequency bands If CAL 2 TRIM gives a peak indication at either extreme of rotation (when planetary drive slips) the oscillator has drifted out of the range of the control and should be recalibrated

An accurate 1 to 160 KC oscillator or oscillator and counter will be required to recalibrate the frequency dial (main osc)

Remove the case turn on the power and allow the instrument to warm up for 30 minutes Connect the external oscillator to the INPUT jack Set its frequency as indicated in the chart below Set the CAL 2 TRIM control two turns from either limit Set the attenuator control to the level used BAND SELECTOR and frequency dial to the position indicated in the chart below Adjust the trimmer indicated in the chart to obtain a peak meter indication Do not change the position of CAL 2 TRIM until the CAL oscilmiddot shylator is checked below

AT BAND SEL FREQ DIAL ADJUST TRllIMER Level used F 90 KC F in 3019 osc

Y E 11E 40 KC i D 10 KC (or 0) D II

C II v 4 KC B 1I B 2 KC

A 1 KC (or 0) A Ii

CAL CAL 1 KC CAL (see below)

12

II

The capacitors in the local oscillator are accumulatively added to the cir shycuit as the BAND SELECTOR switch is rotated from F to CAL thus frequency calibration must be made in the order listed above Band D and A may be calibrated at zero using the local oscillator frequency For this the CampR BAL controls must be adjusted for an on scale indication Band D requires a slightly different zero balance adjustment than band A

Check the calibrate oscillator frequency as follows continuing from A band calibration Set the attenuator (AT) on CAL and BAND SELECTOR on CAL The meter should indicate a peak reading from the calibrate oscillator To check this remove the input signal set controls as given in the chart on the preshyceding page for CAL and rotate the FREQ pointer for peak meter indication The peak meter indication should occur at a frequency pointer position of 1 KC as set for band A If it does not recheck the band calibration If CAL still does not give a peak indication at 1 KC note how far off the frequency is on the dial and proceed with the next paragraph

CALIBRATE OSCILLATOR CALIBRATION

If the calibrate oscillator is no more than 25 cps off as indicated in the preceeding paragraph then pad the capacitor C69 to change the calibrate oscillator by the amount of the error If desired measure the frequency of the CAL oscillator at V7 pin 8 It should be approximately 970 cps This will vary from unit to unit Pad C69 capacitor to change the frequency

If the error is off several 100 cps the fault probably is an error in band calibration or faulty component in the local oscillator (3019)

FREQUENCY SCALE TRACKING

If the frequency tracking on anyone band is off appreciably it may be desired to readjust the appropriate components

Tracking of the DEampF bands is accomplished by changing the LC ratio of L3 to the capacitors in the tank circuit (F trimmer or C94 being the variable trimmers used for this) This is a common adjustment for all three bands normally performed on the F band Moving the last turn on the coil then compensating for the frequency change with nFn trimmer or C94 will change the tracking from 90 to 160 KC on the F band several hundred cycles When the last turn is in position cement it in place with Q dope Recalibrate frequency of D and E bands as previously given Retracking any of the above bands will require resetting and possibly retracking of the ABampC bands

Tracking of the ABampC bands is a common adjustment (normally performed on the C band) by adjusting the ratio of C92 to fiC trimmer C92 changes the band tracking as well as the oscillator frequency C trimmer primarily changes only the oscillator frequency

One method of adjusting the tracking is as follows

1 Connect an electronic counter to V2 pin 2 or 7 Set the frequency dial to 4 KC and BAND SELECTOR to HCII band Adjust trimmer for 504000hCU

cps

13

2 Rotate the frequency dial to 6 KC and note the frequency Adjust C92 to shift the oscillator frequency about 10 times the difference between the oscillator frequency and 506000 cps in the direction of needed corshyrection For example the oscillator reads 506025 cps Adjust I1C92 i to give an oscillator frequency of 250 cps less which is 505775 cps

3 Rotate the pointer to 4 KC and adjust nC1 trimmer for 504000 cps If ICi trimmer does not have enough range set it in mid-position and adshyjust the liFI trimmer This will require recalibrat ion of the iiFn band using C94 (do NOT use liF trimmer) after the llCi band tracking has been adjusted and the frequency of nB and AIi band set

4 Check frequency at 6 KC as in step 2 Repeat the adjustment of steps 2 and 3 if needed Remove the counter lead from V2 pin 2 and 7

5 Recalibrate frequency of C BampA bands as previously given Check IiC r

band tracking by measuring a 4 and 6 KC signal

IF STAGE RETUNING

In the event CAL 2 LEV amplitude cannot be turned high enough to calibrate the instrument tube replacement retuning the IF stage transformers or retuning the crystal filters will be necessary

Connect a signal of about 10 KC to the INPUT JACK Tune in the signal and adjust front panel controls for maximum meter indication with SELECTIVITY switch on 50 - Rotate the top and bottom slugs of T4 then T5 for maxshyimum meter indication Do not rotate T3 slugs

CRYSTAL FILTER RETUNING

Crystal filter transformers are Tl and T2 T3 is adjusted during the crystal filter retuning

A sweep frequency generator and dc coupled oscilloscope are required for proper crystal filter retuning These are special units and not normally available thus it is recommended that the instrument be returned to the factory if the crystal filter needs retuning

If equipment as described below is available and it is desired to retune the crystal filter v-rri te the factory for instructions

1 A sweep frequency generator with center frequency between 20 and 160 KC and sweep width adjustable from about 250 cps to 30 KC It should have a repetition rate of about 2 seconds and output amplitude of approximately 01 volt

2 A direct coupled oscilloscope with a long persistence screen

14

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

The 50 cps crystal filter is down more than 20 db at 200 cps off and 60 db at 250 cps off thus a 0 db balance will cause negligible error when measuring a 300 cps or higher tone

A quick check is to tune in the desired signal remove the input and observe the meter reading due to carrier If it is less than an estimated -25 db tlen any reading above -10 db will be affected less than 1 db NOTE Do nnt set the meter zero on 0 volts The meter zero is used for meter trackshyi~g at -10 db

At low balance a double peak or erratic meter fluctuations may be noted These do not necessarily indicate trouble if the instrument performs satshyisfactorily when measuring a tone

The tube used as VI is critical in determining the degree of balance obtainshyable principally due to heater to cathode leakage Select a 6BH6 tube or a 66616BH6 to give best balance

INTERNAL CALIBRATION

Calibrate the instrument as follows for direct reading in dbm for the cir shycuit impedances listed Calibration for all impedances are based on 0 dbm equals 1 milliwatt of power Step CAL 2b calibrates the frequency Step CAL 2c calibrates the amplitude (meter db or voltage indication) Note Amplitude calibration is not essential for frequency calibration however frequency calibration is essential for amplitude calibration

CAL 1 a Switch positions

BAND SELECTOR to CAL ATTENUATOR to CAL METER to CAL 1 b Adjust CAL 1 LEVEL to give zero on meter DB scale for a 600Q

circuit For other circuit impedances adjust CAL 1 LEVEL to the following meter indications

(1) (3)

-6 for 150Q circuit -67 db for 130Q circuit

(2) (4)

-65 db -90 db

for 135Q circuit for 75Q circuit

CAL 2 a Switch positions

BAND SELECTOR to CAL METER to ON MONITOR to AM ATTEW0ATOR to CAL SELECTIVITY to 50 -

b Adjust FREQUENCY dial pointer to 10 on A band c d

AdjustAdjust

CAL CAL

2 TRIM to peak meter (this calibrates VAR OSC 2 LEV to give zero on meter DB scale for ALL

frequenc~)

circuit impedances (this calibrates amplitude)

This completes the calibration and the instrument is ready for use When precise measurements are needed it is recormnended that a calibration reshycheck be made during the warmup period See APPENDIX A for precautions

INPUT CIRCUIT SELECTION

The input may be unbalanced or balanced for an input impedance of 135Q 600Q or bridging as selected by the UNBAL-BAL switch The input jack on a standard unit takes a 34 spaced dual banana plug Other input conshynector types are supplied when so ordered

7

FREQUENCY SELECTION

Frequency selection is made by means of the BAND SELECTOR FREQUENCY and SELECTIVITY controls The frequency to be measured is tuned in by the large center knob and position ABC etc of the BAND SELECTOR switch

SELECTIVITY

The SELECTDIITY switch selects the crystal filter bandwidth to be used The 50 cycle position is normally used for measuring and the 3 KC and 10 KC for monitoring h~ere signals are spaced wide enough or circuit noise is low enough the 3 or 10 KC positions may be used for measuring above 3 to 6 KC or 10 to 20 KC respectively For precise measurements the internal cali shybration must be for the selectivity position to be used

AMPLITUDE MEASURElVIENT

Connect the signal to be measured to the INPUT JACK (CAUTION See overshyload paragraph) a Switch positions

BAND SELECTOR to desired band SELECTIVITY to 50 shyATTENUATOR to proper level MONITOR to AM (for precise METER to ON measurements)

b Adjust FREQUENCY dial to desired frequency and for maximum meter indication

c Add meter indication and attenuator position algebraically to obtain amplitude of signal being measured

LOW FREQUENCY ffiASUREMENTS

Measurements below about 500 cps require certain precautions The demodushylator must be balanced as given in the Demodulator Balance paragraph to prevent erroneous meter indication due to carrier leak Odd harmonics of 60 cps indicate on the meter due to internal coupling in the unit thus give a beat and cause erroneous meter indication when attempting to measure 60 and 180 cps etc The input impedance below 1 KC with the UNBAL-BAL switch on the l35Q (or below 300 cps on 600Q position) increases due to the impedance ratio of Cl to R2 amp R3 If 135Q or 600Q impedance is desired at low frequencies use the BRIDGE impedance position and an external 135Q or 600Q terminating resistor

OVERLOAD

The amplifiers of this instrument overload before the meter movement is damaged on moderate overloads--however excessive or prolonged overloads should be avoided

Amplitudes of +20 dbm or higher should not be left applied to the instrushyment for longer than a minute or two since the input circuit may heat If +20 dbm or higher amplitude is to be connected continuously a suitable pad should be connected ahead of the instrument to reduce the level below +20 dbm

LOW AMPLITUDE SIGNALS IN PRESENCE OF HIGH AMPLITUDE SIGNALS

Overloading is reduced by introducing attenuation to the input signals Therefore when measuring a low level signal when high levels are also present the more accurate reading will be made when the attenuator step is selected to give a meter reading on the lower 10 db section of the meter scale vfuen measuring circuits on which amplitudes are not approximately known it is suggested that the entire spectrum be first scanned to detershyTIline the highest amplitude signals present This will indicate the lowest level signals which may be apoundcurately measured When highest to lowest ~~els exceed 45 db some inaccuracy due to overload or intermodulation may JG 3usp~cted When measuring harmonics of a single frequency input accurshyate readings may be made 50 db or less for 2nd and 60 db or less for 3rd hi~rmonics

In any case when a low level signal is being measured if the attenuator switch is changed by 10 db and the meter reading also changes 10 db the measurement can be considered accurate

vfuen many input signals are present no simple rule can be followed as the overload point is determined by the peak envelope of the combined signals which may vary with their amplitude and phase

CARRIER MONITORING

The Selective Voltmeter may be used to monitor lower sideband (LSB) upper sideband (USB) amplitude modulated (AM) or frequency modulated (FM)signals Use the 3 kc position of SELECTIVITY switch above 3 kc only and the 10 kc position above 10 kc only

1 Upper and lower sideband monitoring a Connect the input connector to the circuit to be monitored b Switch positions

SELECTIVITY to 3 KC BAND SEL switch amp FREQUENCY DIAL to midband frequency of the

sideband MONITOR switch to LSB or USB as required MONITOR LEVEL--adjust as needed

If the voice or signal from the speaker (or headset if used in HEADSET jack) is weak turn the I1ETER switch off and the ATTENUATOR down until the desired level is reached

2 AM monitoring

To monitor AM signals feed the signal in the INPUT connector turn the seshylectivity to 3 kc or 10 kc set the MONITOR switch to AM tune the FREQshyUENCY dial to the carrier frequency and adjust the amplitude as for single sideband signals

3 FM monitoring

To monitor FM signals by slope detection feed the signal in the INPUT conshynector turn the SELECTIVITY switch to 10 kc set the MONITOR switch to AM adjust the frequency dial for best reception (one side of thA selectivity curve) and adjust the aDlplitude as for single sideband signals

9

AUDIO MONITORING (on units with AUDIO IN jack)

The audio section of the monitor circuit may be used as a amplifier if desired by inserting the signal in the AUDIO

voice frequency IN jack -The outshy

put amplitude is controlled by the MONITOR LEVEL control

10

MAINTENANCE

GENERAL

Most of the components used in the construction of RYCOM instruments are standard parts obtainable from local suppliers Precision components may be purchased from the manufacturer Special items may not be readily avail shyable from the manufacturer All replacement parts are available from RYCOM

For various reasons changes will occasionally appear in the instruction book text parts list and drawings Continued effort is being made to imshyprove circuitry and use better components During the test procedure inshydividual adjustments are made to obtain optimum operation Parts procureshyment difficulties occasiona ly require substitution of different but equivashylent parts

Normal maintenance involves replacement of tubes fuse and pilot lights

The frequency dial lights are accessible from the front by removing the knobs and black dial cover When replacing the frequency knob depress the comshypression spring washer to give sufficient torque for the desired feel in rotating the knob

To remove the instrument from the case for maintenance remove only the screws around the edge of the front panel

PARTS ORDERING

When ordering parts be sure to specify the instrument serial number as well as the instrument model number and individual part number and symbol This will insure receiving the correct replacement parts with a minimum of delay

METER TRACKING

The zero scale

adjust control is used for tracking the meter at -10 db on the

To check or reset meter tracking adjust the unit o on the meter Turn the attenuator up 10 db to Adjust meter zero screw for -10 if needed Turn readjust CAL 2 LEV for O Recheck -10

to measure a frequency read -10 on the meter attenuator dovm 10 db and

at

BASIC AMPLITUDE CALIBRATION

Tube replacement or aging may cause some error in meter indication which is not expected to be more than ~ db This can be corrected by basic recali shybration of the instrument as discussed in Calibration paragraph of the description and given in step form below

1st step a Connect an external signal of about 1500 - of 0 dbm

amplitude to the input connector (NOTE use a preshycision meter to determine the 0 dbm amplitude)

11

b Switch positions ATTENUATOR on 0 MONITOR on AM METER on ON BAND SEL on A SELECTIVITY on 50 FREQUENCY dial to give peak

indication on meter c Adjust CAL 2 LEV to give 0 on meter

2nd step a CAUTION do not change CAL 2 LEV b Switch positions

METER on CAL 1 BAND SELECTOR on CAL c Adjust CAL 1 LEV to give 0 on meter

3rd step a CAUTION do not change CAL 1 LEV or CAL 2 LEV b Switch positions

METER on ON MONITOR on M~

ATTENUATOR on CAL BAND SELECTOR on CAL SELECTIVITY on 50 shy

c Adjust FREQUENCY dial pointer to 10 on band A d Adjust CAL 2 TRIM for peak meter indication e Adjust CAL 3 control located on top of the chassis

behind the meter to give zero on the meter NOTE It is important to set the frequency dial pointer to 10

on A band in this step since adjustment of CAL 2 TRIM for peak meter indication calibrates the frequency dial

FREQUENCY CALIBRATION

Frequency recalibration is made at 1 KC each time CAL 2 TRIM control is adjusted for peak meter indication during calibration however if the frequency tuning drifts appreciably it may be desirable to recalibrate the bands t at are off and all lower frequency bands If CAL 2 TRIM gives a peak indication at either extreme of rotation (when planetary drive slips) the oscillator has drifted out of the range of the control and should be recalibrated

An accurate 1 to 160 KC oscillator or oscillator and counter will be required to recalibrate the frequency dial (main osc)

Remove the case turn on the power and allow the instrument to warm up for 30 minutes Connect the external oscillator to the INPUT jack Set its frequency as indicated in the chart below Set the CAL 2 TRIM control two turns from either limit Set the attenuator control to the level used BAND SELECTOR and frequency dial to the position indicated in the chart below Adjust the trimmer indicated in the chart to obtain a peak meter indication Do not change the position of CAL 2 TRIM until the CAL oscilmiddot shylator is checked below

AT BAND SEL FREQ DIAL ADJUST TRllIMER Level used F 90 KC F in 3019 osc

Y E 11E 40 KC i D 10 KC (or 0) D II

C II v 4 KC B 1I B 2 KC

A 1 KC (or 0) A Ii

CAL CAL 1 KC CAL (see below)

12

II

The capacitors in the local oscillator are accumulatively added to the cir shycuit as the BAND SELECTOR switch is rotated from F to CAL thus frequency calibration must be made in the order listed above Band D and A may be calibrated at zero using the local oscillator frequency For this the CampR BAL controls must be adjusted for an on scale indication Band D requires a slightly different zero balance adjustment than band A

Check the calibrate oscillator frequency as follows continuing from A band calibration Set the attenuator (AT) on CAL and BAND SELECTOR on CAL The meter should indicate a peak reading from the calibrate oscillator To check this remove the input signal set controls as given in the chart on the preshyceding page for CAL and rotate the FREQ pointer for peak meter indication The peak meter indication should occur at a frequency pointer position of 1 KC as set for band A If it does not recheck the band calibration If CAL still does not give a peak indication at 1 KC note how far off the frequency is on the dial and proceed with the next paragraph

CALIBRATE OSCILLATOR CALIBRATION

If the calibrate oscillator is no more than 25 cps off as indicated in the preceeding paragraph then pad the capacitor C69 to change the calibrate oscillator by the amount of the error If desired measure the frequency of the CAL oscillator at V7 pin 8 It should be approximately 970 cps This will vary from unit to unit Pad C69 capacitor to change the frequency

If the error is off several 100 cps the fault probably is an error in band calibration or faulty component in the local oscillator (3019)

FREQUENCY SCALE TRACKING

If the frequency tracking on anyone band is off appreciably it may be desired to readjust the appropriate components

Tracking of the DEampF bands is accomplished by changing the LC ratio of L3 to the capacitors in the tank circuit (F trimmer or C94 being the variable trimmers used for this) This is a common adjustment for all three bands normally performed on the F band Moving the last turn on the coil then compensating for the frequency change with nFn trimmer or C94 will change the tracking from 90 to 160 KC on the F band several hundred cycles When the last turn is in position cement it in place with Q dope Recalibrate frequency of D and E bands as previously given Retracking any of the above bands will require resetting and possibly retracking of the ABampC bands

Tracking of the ABampC bands is a common adjustment (normally performed on the C band) by adjusting the ratio of C92 to fiC trimmer C92 changes the band tracking as well as the oscillator frequency C trimmer primarily changes only the oscillator frequency

One method of adjusting the tracking is as follows

1 Connect an electronic counter to V2 pin 2 or 7 Set the frequency dial to 4 KC and BAND SELECTOR to HCII band Adjust trimmer for 504000hCU

cps

13

2 Rotate the frequency dial to 6 KC and note the frequency Adjust C92 to shift the oscillator frequency about 10 times the difference between the oscillator frequency and 506000 cps in the direction of needed corshyrection For example the oscillator reads 506025 cps Adjust I1C92 i to give an oscillator frequency of 250 cps less which is 505775 cps

3 Rotate the pointer to 4 KC and adjust nC1 trimmer for 504000 cps If ICi trimmer does not have enough range set it in mid-position and adshyjust the liFI trimmer This will require recalibrat ion of the iiFn band using C94 (do NOT use liF trimmer) after the llCi band tracking has been adjusted and the frequency of nB and AIi band set

4 Check frequency at 6 KC as in step 2 Repeat the adjustment of steps 2 and 3 if needed Remove the counter lead from V2 pin 2 and 7

5 Recalibrate frequency of C BampA bands as previously given Check IiC r

band tracking by measuring a 4 and 6 KC signal

IF STAGE RETUNING

In the event CAL 2 LEV amplitude cannot be turned high enough to calibrate the instrument tube replacement retuning the IF stage transformers or retuning the crystal filters will be necessary

Connect a signal of about 10 KC to the INPUT JACK Tune in the signal and adjust front panel controls for maximum meter indication with SELECTIVITY switch on 50 - Rotate the top and bottom slugs of T4 then T5 for maxshyimum meter indication Do not rotate T3 slugs

CRYSTAL FILTER RETUNING

Crystal filter transformers are Tl and T2 T3 is adjusted during the crystal filter retuning

A sweep frequency generator and dc coupled oscilloscope are required for proper crystal filter retuning These are special units and not normally available thus it is recommended that the instrument be returned to the factory if the crystal filter needs retuning

If equipment as described below is available and it is desired to retune the crystal filter v-rri te the factory for instructions

1 A sweep frequency generator with center frequency between 20 and 160 KC and sweep width adjustable from about 250 cps to 30 KC It should have a repetition rate of about 2 seconds and output amplitude of approximately 01 volt

2 A direct coupled oscilloscope with a long persistence screen

14

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

FREQUENCY SELECTION

Frequency selection is made by means of the BAND SELECTOR FREQUENCY and SELECTIVITY controls The frequency to be measured is tuned in by the large center knob and position ABC etc of the BAND SELECTOR switch

SELECTIVITY

The SELECTDIITY switch selects the crystal filter bandwidth to be used The 50 cycle position is normally used for measuring and the 3 KC and 10 KC for monitoring h~ere signals are spaced wide enough or circuit noise is low enough the 3 or 10 KC positions may be used for measuring above 3 to 6 KC or 10 to 20 KC respectively For precise measurements the internal cali shybration must be for the selectivity position to be used

AMPLITUDE MEASURElVIENT

Connect the signal to be measured to the INPUT JACK (CAUTION See overshyload paragraph) a Switch positions

BAND SELECTOR to desired band SELECTIVITY to 50 shyATTENUATOR to proper level MONITOR to AM (for precise METER to ON measurements)

b Adjust FREQUENCY dial to desired frequency and for maximum meter indication

c Add meter indication and attenuator position algebraically to obtain amplitude of signal being measured

LOW FREQUENCY ffiASUREMENTS

Measurements below about 500 cps require certain precautions The demodushylator must be balanced as given in the Demodulator Balance paragraph to prevent erroneous meter indication due to carrier leak Odd harmonics of 60 cps indicate on the meter due to internal coupling in the unit thus give a beat and cause erroneous meter indication when attempting to measure 60 and 180 cps etc The input impedance below 1 KC with the UNBAL-BAL switch on the l35Q (or below 300 cps on 600Q position) increases due to the impedance ratio of Cl to R2 amp R3 If 135Q or 600Q impedance is desired at low frequencies use the BRIDGE impedance position and an external 135Q or 600Q terminating resistor

OVERLOAD

The amplifiers of this instrument overload before the meter movement is damaged on moderate overloads--however excessive or prolonged overloads should be avoided

Amplitudes of +20 dbm or higher should not be left applied to the instrushyment for longer than a minute or two since the input circuit may heat If +20 dbm or higher amplitude is to be connected continuously a suitable pad should be connected ahead of the instrument to reduce the level below +20 dbm

LOW AMPLITUDE SIGNALS IN PRESENCE OF HIGH AMPLITUDE SIGNALS

Overloading is reduced by introducing attenuation to the input signals Therefore when measuring a low level signal when high levels are also present the more accurate reading will be made when the attenuator step is selected to give a meter reading on the lower 10 db section of the meter scale vfuen measuring circuits on which amplitudes are not approximately known it is suggested that the entire spectrum be first scanned to detershyTIline the highest amplitude signals present This will indicate the lowest level signals which may be apoundcurately measured When highest to lowest ~~els exceed 45 db some inaccuracy due to overload or intermodulation may JG 3usp~cted When measuring harmonics of a single frequency input accurshyate readings may be made 50 db or less for 2nd and 60 db or less for 3rd hi~rmonics

In any case when a low level signal is being measured if the attenuator switch is changed by 10 db and the meter reading also changes 10 db the measurement can be considered accurate

vfuen many input signals are present no simple rule can be followed as the overload point is determined by the peak envelope of the combined signals which may vary with their amplitude and phase

CARRIER MONITORING

The Selective Voltmeter may be used to monitor lower sideband (LSB) upper sideband (USB) amplitude modulated (AM) or frequency modulated (FM)signals Use the 3 kc position of SELECTIVITY switch above 3 kc only and the 10 kc position above 10 kc only

1 Upper and lower sideband monitoring a Connect the input connector to the circuit to be monitored b Switch positions

SELECTIVITY to 3 KC BAND SEL switch amp FREQUENCY DIAL to midband frequency of the

sideband MONITOR switch to LSB or USB as required MONITOR LEVEL--adjust as needed

If the voice or signal from the speaker (or headset if used in HEADSET jack) is weak turn the I1ETER switch off and the ATTENUATOR down until the desired level is reached

2 AM monitoring

To monitor AM signals feed the signal in the INPUT connector turn the seshylectivity to 3 kc or 10 kc set the MONITOR switch to AM tune the FREQshyUENCY dial to the carrier frequency and adjust the amplitude as for single sideband signals

3 FM monitoring

To monitor FM signals by slope detection feed the signal in the INPUT conshynector turn the SELECTIVITY switch to 10 kc set the MONITOR switch to AM adjust the frequency dial for best reception (one side of thA selectivity curve) and adjust the aDlplitude as for single sideband signals

9

AUDIO MONITORING (on units with AUDIO IN jack)

The audio section of the monitor circuit may be used as a amplifier if desired by inserting the signal in the AUDIO

voice frequency IN jack -The outshy

put amplitude is controlled by the MONITOR LEVEL control

10

MAINTENANCE

GENERAL

Most of the components used in the construction of RYCOM instruments are standard parts obtainable from local suppliers Precision components may be purchased from the manufacturer Special items may not be readily avail shyable from the manufacturer All replacement parts are available from RYCOM

For various reasons changes will occasionally appear in the instruction book text parts list and drawings Continued effort is being made to imshyprove circuitry and use better components During the test procedure inshydividual adjustments are made to obtain optimum operation Parts procureshyment difficulties occasiona ly require substitution of different but equivashylent parts

Normal maintenance involves replacement of tubes fuse and pilot lights

The frequency dial lights are accessible from the front by removing the knobs and black dial cover When replacing the frequency knob depress the comshypression spring washer to give sufficient torque for the desired feel in rotating the knob

To remove the instrument from the case for maintenance remove only the screws around the edge of the front panel

PARTS ORDERING

When ordering parts be sure to specify the instrument serial number as well as the instrument model number and individual part number and symbol This will insure receiving the correct replacement parts with a minimum of delay

METER TRACKING

The zero scale

adjust control is used for tracking the meter at -10 db on the

To check or reset meter tracking adjust the unit o on the meter Turn the attenuator up 10 db to Adjust meter zero screw for -10 if needed Turn readjust CAL 2 LEV for O Recheck -10

to measure a frequency read -10 on the meter attenuator dovm 10 db and

at

BASIC AMPLITUDE CALIBRATION

Tube replacement or aging may cause some error in meter indication which is not expected to be more than ~ db This can be corrected by basic recali shybration of the instrument as discussed in Calibration paragraph of the description and given in step form below

1st step a Connect an external signal of about 1500 - of 0 dbm

amplitude to the input connector (NOTE use a preshycision meter to determine the 0 dbm amplitude)

11

b Switch positions ATTENUATOR on 0 MONITOR on AM METER on ON BAND SEL on A SELECTIVITY on 50 FREQUENCY dial to give peak

indication on meter c Adjust CAL 2 LEV to give 0 on meter

2nd step a CAUTION do not change CAL 2 LEV b Switch positions

METER on CAL 1 BAND SELECTOR on CAL c Adjust CAL 1 LEV to give 0 on meter

3rd step a CAUTION do not change CAL 1 LEV or CAL 2 LEV b Switch positions

METER on ON MONITOR on M~

ATTENUATOR on CAL BAND SELECTOR on CAL SELECTIVITY on 50 shy

c Adjust FREQUENCY dial pointer to 10 on band A d Adjust CAL 2 TRIM for peak meter indication e Adjust CAL 3 control located on top of the chassis

behind the meter to give zero on the meter NOTE It is important to set the frequency dial pointer to 10

on A band in this step since adjustment of CAL 2 TRIM for peak meter indication calibrates the frequency dial

FREQUENCY CALIBRATION

Frequency recalibration is made at 1 KC each time CAL 2 TRIM control is adjusted for peak meter indication during calibration however if the frequency tuning drifts appreciably it may be desirable to recalibrate the bands t at are off and all lower frequency bands If CAL 2 TRIM gives a peak indication at either extreme of rotation (when planetary drive slips) the oscillator has drifted out of the range of the control and should be recalibrated

An accurate 1 to 160 KC oscillator or oscillator and counter will be required to recalibrate the frequency dial (main osc)

Remove the case turn on the power and allow the instrument to warm up for 30 minutes Connect the external oscillator to the INPUT jack Set its frequency as indicated in the chart below Set the CAL 2 TRIM control two turns from either limit Set the attenuator control to the level used BAND SELECTOR and frequency dial to the position indicated in the chart below Adjust the trimmer indicated in the chart to obtain a peak meter indication Do not change the position of CAL 2 TRIM until the CAL oscilmiddot shylator is checked below

AT BAND SEL FREQ DIAL ADJUST TRllIMER Level used F 90 KC F in 3019 osc

Y E 11E 40 KC i D 10 KC (or 0) D II

C II v 4 KC B 1I B 2 KC

A 1 KC (or 0) A Ii

CAL CAL 1 KC CAL (see below)

12

II

The capacitors in the local oscillator are accumulatively added to the cir shycuit as the BAND SELECTOR switch is rotated from F to CAL thus frequency calibration must be made in the order listed above Band D and A may be calibrated at zero using the local oscillator frequency For this the CampR BAL controls must be adjusted for an on scale indication Band D requires a slightly different zero balance adjustment than band A

Check the calibrate oscillator frequency as follows continuing from A band calibration Set the attenuator (AT) on CAL and BAND SELECTOR on CAL The meter should indicate a peak reading from the calibrate oscillator To check this remove the input signal set controls as given in the chart on the preshyceding page for CAL and rotate the FREQ pointer for peak meter indication The peak meter indication should occur at a frequency pointer position of 1 KC as set for band A If it does not recheck the band calibration If CAL still does not give a peak indication at 1 KC note how far off the frequency is on the dial and proceed with the next paragraph

CALIBRATE OSCILLATOR CALIBRATION

If the calibrate oscillator is no more than 25 cps off as indicated in the preceeding paragraph then pad the capacitor C69 to change the calibrate oscillator by the amount of the error If desired measure the frequency of the CAL oscillator at V7 pin 8 It should be approximately 970 cps This will vary from unit to unit Pad C69 capacitor to change the frequency

If the error is off several 100 cps the fault probably is an error in band calibration or faulty component in the local oscillator (3019)

FREQUENCY SCALE TRACKING

If the frequency tracking on anyone band is off appreciably it may be desired to readjust the appropriate components

Tracking of the DEampF bands is accomplished by changing the LC ratio of L3 to the capacitors in the tank circuit (F trimmer or C94 being the variable trimmers used for this) This is a common adjustment for all three bands normally performed on the F band Moving the last turn on the coil then compensating for the frequency change with nFn trimmer or C94 will change the tracking from 90 to 160 KC on the F band several hundred cycles When the last turn is in position cement it in place with Q dope Recalibrate frequency of D and E bands as previously given Retracking any of the above bands will require resetting and possibly retracking of the ABampC bands

Tracking of the ABampC bands is a common adjustment (normally performed on the C band) by adjusting the ratio of C92 to fiC trimmer C92 changes the band tracking as well as the oscillator frequency C trimmer primarily changes only the oscillator frequency

One method of adjusting the tracking is as follows

1 Connect an electronic counter to V2 pin 2 or 7 Set the frequency dial to 4 KC and BAND SELECTOR to HCII band Adjust trimmer for 504000hCU

cps

13

2 Rotate the frequency dial to 6 KC and note the frequency Adjust C92 to shift the oscillator frequency about 10 times the difference between the oscillator frequency and 506000 cps in the direction of needed corshyrection For example the oscillator reads 506025 cps Adjust I1C92 i to give an oscillator frequency of 250 cps less which is 505775 cps

3 Rotate the pointer to 4 KC and adjust nC1 trimmer for 504000 cps If ICi trimmer does not have enough range set it in mid-position and adshyjust the liFI trimmer This will require recalibrat ion of the iiFn band using C94 (do NOT use liF trimmer) after the llCi band tracking has been adjusted and the frequency of nB and AIi band set

4 Check frequency at 6 KC as in step 2 Repeat the adjustment of steps 2 and 3 if needed Remove the counter lead from V2 pin 2 and 7

5 Recalibrate frequency of C BampA bands as previously given Check IiC r

band tracking by measuring a 4 and 6 KC signal

IF STAGE RETUNING

In the event CAL 2 LEV amplitude cannot be turned high enough to calibrate the instrument tube replacement retuning the IF stage transformers or retuning the crystal filters will be necessary

Connect a signal of about 10 KC to the INPUT JACK Tune in the signal and adjust front panel controls for maximum meter indication with SELECTIVITY switch on 50 - Rotate the top and bottom slugs of T4 then T5 for maxshyimum meter indication Do not rotate T3 slugs

CRYSTAL FILTER RETUNING

Crystal filter transformers are Tl and T2 T3 is adjusted during the crystal filter retuning

A sweep frequency generator and dc coupled oscilloscope are required for proper crystal filter retuning These are special units and not normally available thus it is recommended that the instrument be returned to the factory if the crystal filter needs retuning

If equipment as described below is available and it is desired to retune the crystal filter v-rri te the factory for instructions

1 A sweep frequency generator with center frequency between 20 and 160 KC and sweep width adjustable from about 250 cps to 30 KC It should have a repetition rate of about 2 seconds and output amplitude of approximately 01 volt

2 A direct coupled oscilloscope with a long persistence screen

14

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

LOW AMPLITUDE SIGNALS IN PRESENCE OF HIGH AMPLITUDE SIGNALS

Overloading is reduced by introducing attenuation to the input signals Therefore when measuring a low level signal when high levels are also present the more accurate reading will be made when the attenuator step is selected to give a meter reading on the lower 10 db section of the meter scale vfuen measuring circuits on which amplitudes are not approximately known it is suggested that the entire spectrum be first scanned to detershyTIline the highest amplitude signals present This will indicate the lowest level signals which may be apoundcurately measured When highest to lowest ~~els exceed 45 db some inaccuracy due to overload or intermodulation may JG 3usp~cted When measuring harmonics of a single frequency input accurshyate readings may be made 50 db or less for 2nd and 60 db or less for 3rd hi~rmonics

In any case when a low level signal is being measured if the attenuator switch is changed by 10 db and the meter reading also changes 10 db the measurement can be considered accurate

vfuen many input signals are present no simple rule can be followed as the overload point is determined by the peak envelope of the combined signals which may vary with their amplitude and phase

CARRIER MONITORING

The Selective Voltmeter may be used to monitor lower sideband (LSB) upper sideband (USB) amplitude modulated (AM) or frequency modulated (FM)signals Use the 3 kc position of SELECTIVITY switch above 3 kc only and the 10 kc position above 10 kc only

1 Upper and lower sideband monitoring a Connect the input connector to the circuit to be monitored b Switch positions

SELECTIVITY to 3 KC BAND SEL switch amp FREQUENCY DIAL to midband frequency of the

sideband MONITOR switch to LSB or USB as required MONITOR LEVEL--adjust as needed

If the voice or signal from the speaker (or headset if used in HEADSET jack) is weak turn the I1ETER switch off and the ATTENUATOR down until the desired level is reached

2 AM monitoring

To monitor AM signals feed the signal in the INPUT connector turn the seshylectivity to 3 kc or 10 kc set the MONITOR switch to AM tune the FREQshyUENCY dial to the carrier frequency and adjust the amplitude as for single sideband signals

3 FM monitoring

To monitor FM signals by slope detection feed the signal in the INPUT conshynector turn the SELECTIVITY switch to 10 kc set the MONITOR switch to AM adjust the frequency dial for best reception (one side of thA selectivity curve) and adjust the aDlplitude as for single sideband signals

9

AUDIO MONITORING (on units with AUDIO IN jack)

The audio section of the monitor circuit may be used as a amplifier if desired by inserting the signal in the AUDIO

voice frequency IN jack -The outshy

put amplitude is controlled by the MONITOR LEVEL control

10

MAINTENANCE

GENERAL

Most of the components used in the construction of RYCOM instruments are standard parts obtainable from local suppliers Precision components may be purchased from the manufacturer Special items may not be readily avail shyable from the manufacturer All replacement parts are available from RYCOM

For various reasons changes will occasionally appear in the instruction book text parts list and drawings Continued effort is being made to imshyprove circuitry and use better components During the test procedure inshydividual adjustments are made to obtain optimum operation Parts procureshyment difficulties occasiona ly require substitution of different but equivashylent parts

Normal maintenance involves replacement of tubes fuse and pilot lights

The frequency dial lights are accessible from the front by removing the knobs and black dial cover When replacing the frequency knob depress the comshypression spring washer to give sufficient torque for the desired feel in rotating the knob

To remove the instrument from the case for maintenance remove only the screws around the edge of the front panel

PARTS ORDERING

When ordering parts be sure to specify the instrument serial number as well as the instrument model number and individual part number and symbol This will insure receiving the correct replacement parts with a minimum of delay

METER TRACKING

The zero scale

adjust control is used for tracking the meter at -10 db on the

To check or reset meter tracking adjust the unit o on the meter Turn the attenuator up 10 db to Adjust meter zero screw for -10 if needed Turn readjust CAL 2 LEV for O Recheck -10

to measure a frequency read -10 on the meter attenuator dovm 10 db and

at

BASIC AMPLITUDE CALIBRATION

Tube replacement or aging may cause some error in meter indication which is not expected to be more than ~ db This can be corrected by basic recali shybration of the instrument as discussed in Calibration paragraph of the description and given in step form below

1st step a Connect an external signal of about 1500 - of 0 dbm

amplitude to the input connector (NOTE use a preshycision meter to determine the 0 dbm amplitude)

11

b Switch positions ATTENUATOR on 0 MONITOR on AM METER on ON BAND SEL on A SELECTIVITY on 50 FREQUENCY dial to give peak

indication on meter c Adjust CAL 2 LEV to give 0 on meter

2nd step a CAUTION do not change CAL 2 LEV b Switch positions

METER on CAL 1 BAND SELECTOR on CAL c Adjust CAL 1 LEV to give 0 on meter

3rd step a CAUTION do not change CAL 1 LEV or CAL 2 LEV b Switch positions

METER on ON MONITOR on M~

ATTENUATOR on CAL BAND SELECTOR on CAL SELECTIVITY on 50 shy

c Adjust FREQUENCY dial pointer to 10 on band A d Adjust CAL 2 TRIM for peak meter indication e Adjust CAL 3 control located on top of the chassis

behind the meter to give zero on the meter NOTE It is important to set the frequency dial pointer to 10

on A band in this step since adjustment of CAL 2 TRIM for peak meter indication calibrates the frequency dial

FREQUENCY CALIBRATION

Frequency recalibration is made at 1 KC each time CAL 2 TRIM control is adjusted for peak meter indication during calibration however if the frequency tuning drifts appreciably it may be desirable to recalibrate the bands t at are off and all lower frequency bands If CAL 2 TRIM gives a peak indication at either extreme of rotation (when planetary drive slips) the oscillator has drifted out of the range of the control and should be recalibrated

An accurate 1 to 160 KC oscillator or oscillator and counter will be required to recalibrate the frequency dial (main osc)

Remove the case turn on the power and allow the instrument to warm up for 30 minutes Connect the external oscillator to the INPUT jack Set its frequency as indicated in the chart below Set the CAL 2 TRIM control two turns from either limit Set the attenuator control to the level used BAND SELECTOR and frequency dial to the position indicated in the chart below Adjust the trimmer indicated in the chart to obtain a peak meter indication Do not change the position of CAL 2 TRIM until the CAL oscilmiddot shylator is checked below

AT BAND SEL FREQ DIAL ADJUST TRllIMER Level used F 90 KC F in 3019 osc

Y E 11E 40 KC i D 10 KC (or 0) D II

C II v 4 KC B 1I B 2 KC

A 1 KC (or 0) A Ii

CAL CAL 1 KC CAL (see below)

12

II

The capacitors in the local oscillator are accumulatively added to the cir shycuit as the BAND SELECTOR switch is rotated from F to CAL thus frequency calibration must be made in the order listed above Band D and A may be calibrated at zero using the local oscillator frequency For this the CampR BAL controls must be adjusted for an on scale indication Band D requires a slightly different zero balance adjustment than band A

Check the calibrate oscillator frequency as follows continuing from A band calibration Set the attenuator (AT) on CAL and BAND SELECTOR on CAL The meter should indicate a peak reading from the calibrate oscillator To check this remove the input signal set controls as given in the chart on the preshyceding page for CAL and rotate the FREQ pointer for peak meter indication The peak meter indication should occur at a frequency pointer position of 1 KC as set for band A If it does not recheck the band calibration If CAL still does not give a peak indication at 1 KC note how far off the frequency is on the dial and proceed with the next paragraph

CALIBRATE OSCILLATOR CALIBRATION

If the calibrate oscillator is no more than 25 cps off as indicated in the preceeding paragraph then pad the capacitor C69 to change the calibrate oscillator by the amount of the error If desired measure the frequency of the CAL oscillator at V7 pin 8 It should be approximately 970 cps This will vary from unit to unit Pad C69 capacitor to change the frequency

If the error is off several 100 cps the fault probably is an error in band calibration or faulty component in the local oscillator (3019)

FREQUENCY SCALE TRACKING

If the frequency tracking on anyone band is off appreciably it may be desired to readjust the appropriate components

Tracking of the DEampF bands is accomplished by changing the LC ratio of L3 to the capacitors in the tank circuit (F trimmer or C94 being the variable trimmers used for this) This is a common adjustment for all three bands normally performed on the F band Moving the last turn on the coil then compensating for the frequency change with nFn trimmer or C94 will change the tracking from 90 to 160 KC on the F band several hundred cycles When the last turn is in position cement it in place with Q dope Recalibrate frequency of D and E bands as previously given Retracking any of the above bands will require resetting and possibly retracking of the ABampC bands

Tracking of the ABampC bands is a common adjustment (normally performed on the C band) by adjusting the ratio of C92 to fiC trimmer C92 changes the band tracking as well as the oscillator frequency C trimmer primarily changes only the oscillator frequency

One method of adjusting the tracking is as follows

1 Connect an electronic counter to V2 pin 2 or 7 Set the frequency dial to 4 KC and BAND SELECTOR to HCII band Adjust trimmer for 504000hCU

cps

13

2 Rotate the frequency dial to 6 KC and note the frequency Adjust C92 to shift the oscillator frequency about 10 times the difference between the oscillator frequency and 506000 cps in the direction of needed corshyrection For example the oscillator reads 506025 cps Adjust I1C92 i to give an oscillator frequency of 250 cps less which is 505775 cps

3 Rotate the pointer to 4 KC and adjust nC1 trimmer for 504000 cps If ICi trimmer does not have enough range set it in mid-position and adshyjust the liFI trimmer This will require recalibrat ion of the iiFn band using C94 (do NOT use liF trimmer) after the llCi band tracking has been adjusted and the frequency of nB and AIi band set

4 Check frequency at 6 KC as in step 2 Repeat the adjustment of steps 2 and 3 if needed Remove the counter lead from V2 pin 2 and 7

5 Recalibrate frequency of C BampA bands as previously given Check IiC r

band tracking by measuring a 4 and 6 KC signal

IF STAGE RETUNING

In the event CAL 2 LEV amplitude cannot be turned high enough to calibrate the instrument tube replacement retuning the IF stage transformers or retuning the crystal filters will be necessary

Connect a signal of about 10 KC to the INPUT JACK Tune in the signal and adjust front panel controls for maximum meter indication with SELECTIVITY switch on 50 - Rotate the top and bottom slugs of T4 then T5 for maxshyimum meter indication Do not rotate T3 slugs

CRYSTAL FILTER RETUNING

Crystal filter transformers are Tl and T2 T3 is adjusted during the crystal filter retuning

A sweep frequency generator and dc coupled oscilloscope are required for proper crystal filter retuning These are special units and not normally available thus it is recommended that the instrument be returned to the factory if the crystal filter needs retuning

If equipment as described below is available and it is desired to retune the crystal filter v-rri te the factory for instructions

1 A sweep frequency generator with center frequency between 20 and 160 KC and sweep width adjustable from about 250 cps to 30 KC It should have a repetition rate of about 2 seconds and output amplitude of approximately 01 volt

2 A direct coupled oscilloscope with a long persistence screen

14

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

AUDIO MONITORING (on units with AUDIO IN jack)

The audio section of the monitor circuit may be used as a amplifier if desired by inserting the signal in the AUDIO

voice frequency IN jack -The outshy

put amplitude is controlled by the MONITOR LEVEL control

10

MAINTENANCE

GENERAL

Most of the components used in the construction of RYCOM instruments are standard parts obtainable from local suppliers Precision components may be purchased from the manufacturer Special items may not be readily avail shyable from the manufacturer All replacement parts are available from RYCOM

For various reasons changes will occasionally appear in the instruction book text parts list and drawings Continued effort is being made to imshyprove circuitry and use better components During the test procedure inshydividual adjustments are made to obtain optimum operation Parts procureshyment difficulties occasiona ly require substitution of different but equivashylent parts

Normal maintenance involves replacement of tubes fuse and pilot lights

The frequency dial lights are accessible from the front by removing the knobs and black dial cover When replacing the frequency knob depress the comshypression spring washer to give sufficient torque for the desired feel in rotating the knob

To remove the instrument from the case for maintenance remove only the screws around the edge of the front panel

PARTS ORDERING

When ordering parts be sure to specify the instrument serial number as well as the instrument model number and individual part number and symbol This will insure receiving the correct replacement parts with a minimum of delay

METER TRACKING

The zero scale

adjust control is used for tracking the meter at -10 db on the

To check or reset meter tracking adjust the unit o on the meter Turn the attenuator up 10 db to Adjust meter zero screw for -10 if needed Turn readjust CAL 2 LEV for O Recheck -10

to measure a frequency read -10 on the meter attenuator dovm 10 db and

at

BASIC AMPLITUDE CALIBRATION

Tube replacement or aging may cause some error in meter indication which is not expected to be more than ~ db This can be corrected by basic recali shybration of the instrument as discussed in Calibration paragraph of the description and given in step form below

1st step a Connect an external signal of about 1500 - of 0 dbm

amplitude to the input connector (NOTE use a preshycision meter to determine the 0 dbm amplitude)

11

b Switch positions ATTENUATOR on 0 MONITOR on AM METER on ON BAND SEL on A SELECTIVITY on 50 FREQUENCY dial to give peak

indication on meter c Adjust CAL 2 LEV to give 0 on meter

2nd step a CAUTION do not change CAL 2 LEV b Switch positions

METER on CAL 1 BAND SELECTOR on CAL c Adjust CAL 1 LEV to give 0 on meter

3rd step a CAUTION do not change CAL 1 LEV or CAL 2 LEV b Switch positions

METER on ON MONITOR on M~

ATTENUATOR on CAL BAND SELECTOR on CAL SELECTIVITY on 50 shy

c Adjust FREQUENCY dial pointer to 10 on band A d Adjust CAL 2 TRIM for peak meter indication e Adjust CAL 3 control located on top of the chassis

behind the meter to give zero on the meter NOTE It is important to set the frequency dial pointer to 10

on A band in this step since adjustment of CAL 2 TRIM for peak meter indication calibrates the frequency dial

FREQUENCY CALIBRATION

Frequency recalibration is made at 1 KC each time CAL 2 TRIM control is adjusted for peak meter indication during calibration however if the frequency tuning drifts appreciably it may be desirable to recalibrate the bands t at are off and all lower frequency bands If CAL 2 TRIM gives a peak indication at either extreme of rotation (when planetary drive slips) the oscillator has drifted out of the range of the control and should be recalibrated

An accurate 1 to 160 KC oscillator or oscillator and counter will be required to recalibrate the frequency dial (main osc)

Remove the case turn on the power and allow the instrument to warm up for 30 minutes Connect the external oscillator to the INPUT jack Set its frequency as indicated in the chart below Set the CAL 2 TRIM control two turns from either limit Set the attenuator control to the level used BAND SELECTOR and frequency dial to the position indicated in the chart below Adjust the trimmer indicated in the chart to obtain a peak meter indication Do not change the position of CAL 2 TRIM until the CAL oscilmiddot shylator is checked below

AT BAND SEL FREQ DIAL ADJUST TRllIMER Level used F 90 KC F in 3019 osc

Y E 11E 40 KC i D 10 KC (or 0) D II

C II v 4 KC B 1I B 2 KC

A 1 KC (or 0) A Ii

CAL CAL 1 KC CAL (see below)

12

II

The capacitors in the local oscillator are accumulatively added to the cir shycuit as the BAND SELECTOR switch is rotated from F to CAL thus frequency calibration must be made in the order listed above Band D and A may be calibrated at zero using the local oscillator frequency For this the CampR BAL controls must be adjusted for an on scale indication Band D requires a slightly different zero balance adjustment than band A

Check the calibrate oscillator frequency as follows continuing from A band calibration Set the attenuator (AT) on CAL and BAND SELECTOR on CAL The meter should indicate a peak reading from the calibrate oscillator To check this remove the input signal set controls as given in the chart on the preshyceding page for CAL and rotate the FREQ pointer for peak meter indication The peak meter indication should occur at a frequency pointer position of 1 KC as set for band A If it does not recheck the band calibration If CAL still does not give a peak indication at 1 KC note how far off the frequency is on the dial and proceed with the next paragraph

CALIBRATE OSCILLATOR CALIBRATION

If the calibrate oscillator is no more than 25 cps off as indicated in the preceeding paragraph then pad the capacitor C69 to change the calibrate oscillator by the amount of the error If desired measure the frequency of the CAL oscillator at V7 pin 8 It should be approximately 970 cps This will vary from unit to unit Pad C69 capacitor to change the frequency

If the error is off several 100 cps the fault probably is an error in band calibration or faulty component in the local oscillator (3019)

FREQUENCY SCALE TRACKING

If the frequency tracking on anyone band is off appreciably it may be desired to readjust the appropriate components

Tracking of the DEampF bands is accomplished by changing the LC ratio of L3 to the capacitors in the tank circuit (F trimmer or C94 being the variable trimmers used for this) This is a common adjustment for all three bands normally performed on the F band Moving the last turn on the coil then compensating for the frequency change with nFn trimmer or C94 will change the tracking from 90 to 160 KC on the F band several hundred cycles When the last turn is in position cement it in place with Q dope Recalibrate frequency of D and E bands as previously given Retracking any of the above bands will require resetting and possibly retracking of the ABampC bands

Tracking of the ABampC bands is a common adjustment (normally performed on the C band) by adjusting the ratio of C92 to fiC trimmer C92 changes the band tracking as well as the oscillator frequency C trimmer primarily changes only the oscillator frequency

One method of adjusting the tracking is as follows

1 Connect an electronic counter to V2 pin 2 or 7 Set the frequency dial to 4 KC and BAND SELECTOR to HCII band Adjust trimmer for 504000hCU

cps

13

2 Rotate the frequency dial to 6 KC and note the frequency Adjust C92 to shift the oscillator frequency about 10 times the difference between the oscillator frequency and 506000 cps in the direction of needed corshyrection For example the oscillator reads 506025 cps Adjust I1C92 i to give an oscillator frequency of 250 cps less which is 505775 cps

3 Rotate the pointer to 4 KC and adjust nC1 trimmer for 504000 cps If ICi trimmer does not have enough range set it in mid-position and adshyjust the liFI trimmer This will require recalibrat ion of the iiFn band using C94 (do NOT use liF trimmer) after the llCi band tracking has been adjusted and the frequency of nB and AIi band set

4 Check frequency at 6 KC as in step 2 Repeat the adjustment of steps 2 and 3 if needed Remove the counter lead from V2 pin 2 and 7

5 Recalibrate frequency of C BampA bands as previously given Check IiC r

band tracking by measuring a 4 and 6 KC signal

IF STAGE RETUNING

In the event CAL 2 LEV amplitude cannot be turned high enough to calibrate the instrument tube replacement retuning the IF stage transformers or retuning the crystal filters will be necessary

Connect a signal of about 10 KC to the INPUT JACK Tune in the signal and adjust front panel controls for maximum meter indication with SELECTIVITY switch on 50 - Rotate the top and bottom slugs of T4 then T5 for maxshyimum meter indication Do not rotate T3 slugs

CRYSTAL FILTER RETUNING

Crystal filter transformers are Tl and T2 T3 is adjusted during the crystal filter retuning

A sweep frequency generator and dc coupled oscilloscope are required for proper crystal filter retuning These are special units and not normally available thus it is recommended that the instrument be returned to the factory if the crystal filter needs retuning

If equipment as described below is available and it is desired to retune the crystal filter v-rri te the factory for instructions

1 A sweep frequency generator with center frequency between 20 and 160 KC and sweep width adjustable from about 250 cps to 30 KC It should have a repetition rate of about 2 seconds and output amplitude of approximately 01 volt

2 A direct coupled oscilloscope with a long persistence screen

14

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

MAINTENANCE

GENERAL

Most of the components used in the construction of RYCOM instruments are standard parts obtainable from local suppliers Precision components may be purchased from the manufacturer Special items may not be readily avail shyable from the manufacturer All replacement parts are available from RYCOM

For various reasons changes will occasionally appear in the instruction book text parts list and drawings Continued effort is being made to imshyprove circuitry and use better components During the test procedure inshydividual adjustments are made to obtain optimum operation Parts procureshyment difficulties occasiona ly require substitution of different but equivashylent parts

Normal maintenance involves replacement of tubes fuse and pilot lights

The frequency dial lights are accessible from the front by removing the knobs and black dial cover When replacing the frequency knob depress the comshypression spring washer to give sufficient torque for the desired feel in rotating the knob

To remove the instrument from the case for maintenance remove only the screws around the edge of the front panel

PARTS ORDERING

When ordering parts be sure to specify the instrument serial number as well as the instrument model number and individual part number and symbol This will insure receiving the correct replacement parts with a minimum of delay

METER TRACKING

The zero scale

adjust control is used for tracking the meter at -10 db on the

To check or reset meter tracking adjust the unit o on the meter Turn the attenuator up 10 db to Adjust meter zero screw for -10 if needed Turn readjust CAL 2 LEV for O Recheck -10

to measure a frequency read -10 on the meter attenuator dovm 10 db and

at

BASIC AMPLITUDE CALIBRATION

Tube replacement or aging may cause some error in meter indication which is not expected to be more than ~ db This can be corrected by basic recali shybration of the instrument as discussed in Calibration paragraph of the description and given in step form below

1st step a Connect an external signal of about 1500 - of 0 dbm

amplitude to the input connector (NOTE use a preshycision meter to determine the 0 dbm amplitude)

11

b Switch positions ATTENUATOR on 0 MONITOR on AM METER on ON BAND SEL on A SELECTIVITY on 50 FREQUENCY dial to give peak

indication on meter c Adjust CAL 2 LEV to give 0 on meter

2nd step a CAUTION do not change CAL 2 LEV b Switch positions

METER on CAL 1 BAND SELECTOR on CAL c Adjust CAL 1 LEV to give 0 on meter

3rd step a CAUTION do not change CAL 1 LEV or CAL 2 LEV b Switch positions

METER on ON MONITOR on M~

ATTENUATOR on CAL BAND SELECTOR on CAL SELECTIVITY on 50 shy

c Adjust FREQUENCY dial pointer to 10 on band A d Adjust CAL 2 TRIM for peak meter indication e Adjust CAL 3 control located on top of the chassis

behind the meter to give zero on the meter NOTE It is important to set the frequency dial pointer to 10

on A band in this step since adjustment of CAL 2 TRIM for peak meter indication calibrates the frequency dial

FREQUENCY CALIBRATION

Frequency recalibration is made at 1 KC each time CAL 2 TRIM control is adjusted for peak meter indication during calibration however if the frequency tuning drifts appreciably it may be desirable to recalibrate the bands t at are off and all lower frequency bands If CAL 2 TRIM gives a peak indication at either extreme of rotation (when planetary drive slips) the oscillator has drifted out of the range of the control and should be recalibrated

An accurate 1 to 160 KC oscillator or oscillator and counter will be required to recalibrate the frequency dial (main osc)

Remove the case turn on the power and allow the instrument to warm up for 30 minutes Connect the external oscillator to the INPUT jack Set its frequency as indicated in the chart below Set the CAL 2 TRIM control two turns from either limit Set the attenuator control to the level used BAND SELECTOR and frequency dial to the position indicated in the chart below Adjust the trimmer indicated in the chart to obtain a peak meter indication Do not change the position of CAL 2 TRIM until the CAL oscilmiddot shylator is checked below

AT BAND SEL FREQ DIAL ADJUST TRllIMER Level used F 90 KC F in 3019 osc

Y E 11E 40 KC i D 10 KC (or 0) D II

C II v 4 KC B 1I B 2 KC

A 1 KC (or 0) A Ii

CAL CAL 1 KC CAL (see below)

12

II

The capacitors in the local oscillator are accumulatively added to the cir shycuit as the BAND SELECTOR switch is rotated from F to CAL thus frequency calibration must be made in the order listed above Band D and A may be calibrated at zero using the local oscillator frequency For this the CampR BAL controls must be adjusted for an on scale indication Band D requires a slightly different zero balance adjustment than band A

Check the calibrate oscillator frequency as follows continuing from A band calibration Set the attenuator (AT) on CAL and BAND SELECTOR on CAL The meter should indicate a peak reading from the calibrate oscillator To check this remove the input signal set controls as given in the chart on the preshyceding page for CAL and rotate the FREQ pointer for peak meter indication The peak meter indication should occur at a frequency pointer position of 1 KC as set for band A If it does not recheck the band calibration If CAL still does not give a peak indication at 1 KC note how far off the frequency is on the dial and proceed with the next paragraph

CALIBRATE OSCILLATOR CALIBRATION

If the calibrate oscillator is no more than 25 cps off as indicated in the preceeding paragraph then pad the capacitor C69 to change the calibrate oscillator by the amount of the error If desired measure the frequency of the CAL oscillator at V7 pin 8 It should be approximately 970 cps This will vary from unit to unit Pad C69 capacitor to change the frequency

If the error is off several 100 cps the fault probably is an error in band calibration or faulty component in the local oscillator (3019)

FREQUENCY SCALE TRACKING

If the frequency tracking on anyone band is off appreciably it may be desired to readjust the appropriate components

Tracking of the DEampF bands is accomplished by changing the LC ratio of L3 to the capacitors in the tank circuit (F trimmer or C94 being the variable trimmers used for this) This is a common adjustment for all three bands normally performed on the F band Moving the last turn on the coil then compensating for the frequency change with nFn trimmer or C94 will change the tracking from 90 to 160 KC on the F band several hundred cycles When the last turn is in position cement it in place with Q dope Recalibrate frequency of D and E bands as previously given Retracking any of the above bands will require resetting and possibly retracking of the ABampC bands

Tracking of the ABampC bands is a common adjustment (normally performed on the C band) by adjusting the ratio of C92 to fiC trimmer C92 changes the band tracking as well as the oscillator frequency C trimmer primarily changes only the oscillator frequency

One method of adjusting the tracking is as follows

1 Connect an electronic counter to V2 pin 2 or 7 Set the frequency dial to 4 KC and BAND SELECTOR to HCII band Adjust trimmer for 504000hCU

cps

13

2 Rotate the frequency dial to 6 KC and note the frequency Adjust C92 to shift the oscillator frequency about 10 times the difference between the oscillator frequency and 506000 cps in the direction of needed corshyrection For example the oscillator reads 506025 cps Adjust I1C92 i to give an oscillator frequency of 250 cps less which is 505775 cps

3 Rotate the pointer to 4 KC and adjust nC1 trimmer for 504000 cps If ICi trimmer does not have enough range set it in mid-position and adshyjust the liFI trimmer This will require recalibrat ion of the iiFn band using C94 (do NOT use liF trimmer) after the llCi band tracking has been adjusted and the frequency of nB and AIi band set

4 Check frequency at 6 KC as in step 2 Repeat the adjustment of steps 2 and 3 if needed Remove the counter lead from V2 pin 2 and 7

5 Recalibrate frequency of C BampA bands as previously given Check IiC r

band tracking by measuring a 4 and 6 KC signal

IF STAGE RETUNING

In the event CAL 2 LEV amplitude cannot be turned high enough to calibrate the instrument tube replacement retuning the IF stage transformers or retuning the crystal filters will be necessary

Connect a signal of about 10 KC to the INPUT JACK Tune in the signal and adjust front panel controls for maximum meter indication with SELECTIVITY switch on 50 - Rotate the top and bottom slugs of T4 then T5 for maxshyimum meter indication Do not rotate T3 slugs

CRYSTAL FILTER RETUNING

Crystal filter transformers are Tl and T2 T3 is adjusted during the crystal filter retuning

A sweep frequency generator and dc coupled oscilloscope are required for proper crystal filter retuning These are special units and not normally available thus it is recommended that the instrument be returned to the factory if the crystal filter needs retuning

If equipment as described below is available and it is desired to retune the crystal filter v-rri te the factory for instructions

1 A sweep frequency generator with center frequency between 20 and 160 KC and sweep width adjustable from about 250 cps to 30 KC It should have a repetition rate of about 2 seconds and output amplitude of approximately 01 volt

2 A direct coupled oscilloscope with a long persistence screen

14

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

b Switch positions ATTENUATOR on 0 MONITOR on AM METER on ON BAND SEL on A SELECTIVITY on 50 FREQUENCY dial to give peak

indication on meter c Adjust CAL 2 LEV to give 0 on meter

2nd step a CAUTION do not change CAL 2 LEV b Switch positions

METER on CAL 1 BAND SELECTOR on CAL c Adjust CAL 1 LEV to give 0 on meter

3rd step a CAUTION do not change CAL 1 LEV or CAL 2 LEV b Switch positions

METER on ON MONITOR on M~

ATTENUATOR on CAL BAND SELECTOR on CAL SELECTIVITY on 50 shy

c Adjust FREQUENCY dial pointer to 10 on band A d Adjust CAL 2 TRIM for peak meter indication e Adjust CAL 3 control located on top of the chassis

behind the meter to give zero on the meter NOTE It is important to set the frequency dial pointer to 10

on A band in this step since adjustment of CAL 2 TRIM for peak meter indication calibrates the frequency dial

FREQUENCY CALIBRATION

Frequency recalibration is made at 1 KC each time CAL 2 TRIM control is adjusted for peak meter indication during calibration however if the frequency tuning drifts appreciably it may be desirable to recalibrate the bands t at are off and all lower frequency bands If CAL 2 TRIM gives a peak indication at either extreme of rotation (when planetary drive slips) the oscillator has drifted out of the range of the control and should be recalibrated

An accurate 1 to 160 KC oscillator or oscillator and counter will be required to recalibrate the frequency dial (main osc)

Remove the case turn on the power and allow the instrument to warm up for 30 minutes Connect the external oscillator to the INPUT jack Set its frequency as indicated in the chart below Set the CAL 2 TRIM control two turns from either limit Set the attenuator control to the level used BAND SELECTOR and frequency dial to the position indicated in the chart below Adjust the trimmer indicated in the chart to obtain a peak meter indication Do not change the position of CAL 2 TRIM until the CAL oscilmiddot shylator is checked below

AT BAND SEL FREQ DIAL ADJUST TRllIMER Level used F 90 KC F in 3019 osc

Y E 11E 40 KC i D 10 KC (or 0) D II

C II v 4 KC B 1I B 2 KC

A 1 KC (or 0) A Ii

CAL CAL 1 KC CAL (see below)

12

II

The capacitors in the local oscillator are accumulatively added to the cir shycuit as the BAND SELECTOR switch is rotated from F to CAL thus frequency calibration must be made in the order listed above Band D and A may be calibrated at zero using the local oscillator frequency For this the CampR BAL controls must be adjusted for an on scale indication Band D requires a slightly different zero balance adjustment than band A

Check the calibrate oscillator frequency as follows continuing from A band calibration Set the attenuator (AT) on CAL and BAND SELECTOR on CAL The meter should indicate a peak reading from the calibrate oscillator To check this remove the input signal set controls as given in the chart on the preshyceding page for CAL and rotate the FREQ pointer for peak meter indication The peak meter indication should occur at a frequency pointer position of 1 KC as set for band A If it does not recheck the band calibration If CAL still does not give a peak indication at 1 KC note how far off the frequency is on the dial and proceed with the next paragraph

CALIBRATE OSCILLATOR CALIBRATION

If the calibrate oscillator is no more than 25 cps off as indicated in the preceeding paragraph then pad the capacitor C69 to change the calibrate oscillator by the amount of the error If desired measure the frequency of the CAL oscillator at V7 pin 8 It should be approximately 970 cps This will vary from unit to unit Pad C69 capacitor to change the frequency

If the error is off several 100 cps the fault probably is an error in band calibration or faulty component in the local oscillator (3019)

FREQUENCY SCALE TRACKING

If the frequency tracking on anyone band is off appreciably it may be desired to readjust the appropriate components

Tracking of the DEampF bands is accomplished by changing the LC ratio of L3 to the capacitors in the tank circuit (F trimmer or C94 being the variable trimmers used for this) This is a common adjustment for all three bands normally performed on the F band Moving the last turn on the coil then compensating for the frequency change with nFn trimmer or C94 will change the tracking from 90 to 160 KC on the F band several hundred cycles When the last turn is in position cement it in place with Q dope Recalibrate frequency of D and E bands as previously given Retracking any of the above bands will require resetting and possibly retracking of the ABampC bands

Tracking of the ABampC bands is a common adjustment (normally performed on the C band) by adjusting the ratio of C92 to fiC trimmer C92 changes the band tracking as well as the oscillator frequency C trimmer primarily changes only the oscillator frequency

One method of adjusting the tracking is as follows

1 Connect an electronic counter to V2 pin 2 or 7 Set the frequency dial to 4 KC and BAND SELECTOR to HCII band Adjust trimmer for 504000hCU

cps

13

2 Rotate the frequency dial to 6 KC and note the frequency Adjust C92 to shift the oscillator frequency about 10 times the difference between the oscillator frequency and 506000 cps in the direction of needed corshyrection For example the oscillator reads 506025 cps Adjust I1C92 i to give an oscillator frequency of 250 cps less which is 505775 cps

3 Rotate the pointer to 4 KC and adjust nC1 trimmer for 504000 cps If ICi trimmer does not have enough range set it in mid-position and adshyjust the liFI trimmer This will require recalibrat ion of the iiFn band using C94 (do NOT use liF trimmer) after the llCi band tracking has been adjusted and the frequency of nB and AIi band set

4 Check frequency at 6 KC as in step 2 Repeat the adjustment of steps 2 and 3 if needed Remove the counter lead from V2 pin 2 and 7

5 Recalibrate frequency of C BampA bands as previously given Check IiC r

band tracking by measuring a 4 and 6 KC signal

IF STAGE RETUNING

In the event CAL 2 LEV amplitude cannot be turned high enough to calibrate the instrument tube replacement retuning the IF stage transformers or retuning the crystal filters will be necessary

Connect a signal of about 10 KC to the INPUT JACK Tune in the signal and adjust front panel controls for maximum meter indication with SELECTIVITY switch on 50 - Rotate the top and bottom slugs of T4 then T5 for maxshyimum meter indication Do not rotate T3 slugs

CRYSTAL FILTER RETUNING

Crystal filter transformers are Tl and T2 T3 is adjusted during the crystal filter retuning

A sweep frequency generator and dc coupled oscilloscope are required for proper crystal filter retuning These are special units and not normally available thus it is recommended that the instrument be returned to the factory if the crystal filter needs retuning

If equipment as described below is available and it is desired to retune the crystal filter v-rri te the factory for instructions

1 A sweep frequency generator with center frequency between 20 and 160 KC and sweep width adjustable from about 250 cps to 30 KC It should have a repetition rate of about 2 seconds and output amplitude of approximately 01 volt

2 A direct coupled oscilloscope with a long persistence screen

14

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

The capacitors in the local oscillator are accumulatively added to the cir shycuit as the BAND SELECTOR switch is rotated from F to CAL thus frequency calibration must be made in the order listed above Band D and A may be calibrated at zero using the local oscillator frequency For this the CampR BAL controls must be adjusted for an on scale indication Band D requires a slightly different zero balance adjustment than band A

Check the calibrate oscillator frequency as follows continuing from A band calibration Set the attenuator (AT) on CAL and BAND SELECTOR on CAL The meter should indicate a peak reading from the calibrate oscillator To check this remove the input signal set controls as given in the chart on the preshyceding page for CAL and rotate the FREQ pointer for peak meter indication The peak meter indication should occur at a frequency pointer position of 1 KC as set for band A If it does not recheck the band calibration If CAL still does not give a peak indication at 1 KC note how far off the frequency is on the dial and proceed with the next paragraph

CALIBRATE OSCILLATOR CALIBRATION

If the calibrate oscillator is no more than 25 cps off as indicated in the preceeding paragraph then pad the capacitor C69 to change the calibrate oscillator by the amount of the error If desired measure the frequency of the CAL oscillator at V7 pin 8 It should be approximately 970 cps This will vary from unit to unit Pad C69 capacitor to change the frequency

If the error is off several 100 cps the fault probably is an error in band calibration or faulty component in the local oscillator (3019)

FREQUENCY SCALE TRACKING

If the frequency tracking on anyone band is off appreciably it may be desired to readjust the appropriate components

Tracking of the DEampF bands is accomplished by changing the LC ratio of L3 to the capacitors in the tank circuit (F trimmer or C94 being the variable trimmers used for this) This is a common adjustment for all three bands normally performed on the F band Moving the last turn on the coil then compensating for the frequency change with nFn trimmer or C94 will change the tracking from 90 to 160 KC on the F band several hundred cycles When the last turn is in position cement it in place with Q dope Recalibrate frequency of D and E bands as previously given Retracking any of the above bands will require resetting and possibly retracking of the ABampC bands

Tracking of the ABampC bands is a common adjustment (normally performed on the C band) by adjusting the ratio of C92 to fiC trimmer C92 changes the band tracking as well as the oscillator frequency C trimmer primarily changes only the oscillator frequency

One method of adjusting the tracking is as follows

1 Connect an electronic counter to V2 pin 2 or 7 Set the frequency dial to 4 KC and BAND SELECTOR to HCII band Adjust trimmer for 504000hCU

cps

13

2 Rotate the frequency dial to 6 KC and note the frequency Adjust C92 to shift the oscillator frequency about 10 times the difference between the oscillator frequency and 506000 cps in the direction of needed corshyrection For example the oscillator reads 506025 cps Adjust I1C92 i to give an oscillator frequency of 250 cps less which is 505775 cps

3 Rotate the pointer to 4 KC and adjust nC1 trimmer for 504000 cps If ICi trimmer does not have enough range set it in mid-position and adshyjust the liFI trimmer This will require recalibrat ion of the iiFn band using C94 (do NOT use liF trimmer) after the llCi band tracking has been adjusted and the frequency of nB and AIi band set

4 Check frequency at 6 KC as in step 2 Repeat the adjustment of steps 2 and 3 if needed Remove the counter lead from V2 pin 2 and 7

5 Recalibrate frequency of C BampA bands as previously given Check IiC r

band tracking by measuring a 4 and 6 KC signal

IF STAGE RETUNING

In the event CAL 2 LEV amplitude cannot be turned high enough to calibrate the instrument tube replacement retuning the IF stage transformers or retuning the crystal filters will be necessary

Connect a signal of about 10 KC to the INPUT JACK Tune in the signal and adjust front panel controls for maximum meter indication with SELECTIVITY switch on 50 - Rotate the top and bottom slugs of T4 then T5 for maxshyimum meter indication Do not rotate T3 slugs

CRYSTAL FILTER RETUNING

Crystal filter transformers are Tl and T2 T3 is adjusted during the crystal filter retuning

A sweep frequency generator and dc coupled oscilloscope are required for proper crystal filter retuning These are special units and not normally available thus it is recommended that the instrument be returned to the factory if the crystal filter needs retuning

If equipment as described below is available and it is desired to retune the crystal filter v-rri te the factory for instructions

1 A sweep frequency generator with center frequency between 20 and 160 KC and sweep width adjustable from about 250 cps to 30 KC It should have a repetition rate of about 2 seconds and output amplitude of approximately 01 volt

2 A direct coupled oscilloscope with a long persistence screen

14

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

2 Rotate the frequency dial to 6 KC and note the frequency Adjust C92 to shift the oscillator frequency about 10 times the difference between the oscillator frequency and 506000 cps in the direction of needed corshyrection For example the oscillator reads 506025 cps Adjust I1C92 i to give an oscillator frequency of 250 cps less which is 505775 cps

3 Rotate the pointer to 4 KC and adjust nC1 trimmer for 504000 cps If ICi trimmer does not have enough range set it in mid-position and adshyjust the liFI trimmer This will require recalibrat ion of the iiFn band using C94 (do NOT use liF trimmer) after the llCi band tracking has been adjusted and the frequency of nB and AIi band set

4 Check frequency at 6 KC as in step 2 Repeat the adjustment of steps 2 and 3 if needed Remove the counter lead from V2 pin 2 and 7

5 Recalibrate frequency of C BampA bands as previously given Check IiC r

band tracking by measuring a 4 and 6 KC signal

IF STAGE RETUNING

In the event CAL 2 LEV amplitude cannot be turned high enough to calibrate the instrument tube replacement retuning the IF stage transformers or retuning the crystal filters will be necessary

Connect a signal of about 10 KC to the INPUT JACK Tune in the signal and adjust front panel controls for maximum meter indication with SELECTIVITY switch on 50 - Rotate the top and bottom slugs of T4 then T5 for maxshyimum meter indication Do not rotate T3 slugs

CRYSTAL FILTER RETUNING

Crystal filter transformers are Tl and T2 T3 is adjusted during the crystal filter retuning

A sweep frequency generator and dc coupled oscilloscope are required for proper crystal filter retuning These are special units and not normally available thus it is recommended that the instrument be returned to the factory if the crystal filter needs retuning

If equipment as described below is available and it is desired to retune the crystal filter v-rri te the factory for instructions

1 A sweep frequency generator with center frequency between 20 and 160 KC and sweep width adjustable from about 250 cps to 30 KC It should have a repetition rate of about 2 seconds and output amplitude of approximately 01 volt

2 A direct coupled oscilloscope with a long persistence screen

14

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

LIST OF MANUFACTURERS

Symbol is listed in parts list under manufacturer

Symbol A Alden Products Company B All Star Products Inc C Allen-Bradley Company D Bussman Mfg Company E jmiddotJC Inc - ~

F CTS Corporation G Cletron Inc H EF Johnson Company I Electra Mfg Company or Kidco Inc J Electro Motive Mfg Company K Electron Products Company L Erie Resistor Corporation M Good-All Mfg Company N International Rectifier Corp o James Knights Company P Ohmite Mfg Company Q Assembly Products Inc R RAILWAY CO~~UNICATIONS INC S Sherold Crystal Corporation T Stan~ck Winding Company U SWitchcraft Inc V Sylvania Electric Products Inc W Transformer Technicians Inc X Wilco Corporation Y General Instrument Z Semicon Inc

List of abbreviations in parts list

A Linear taper AR Selected as required (Nominal value listed)

G~W Guaranteed minimum value HT High torque S Shaft (meas from end of bushing) SD Screwdriver slot in shaft

VAR Variable

T585-p650-9FE 15

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

PARTS

Symbol Part No Mfg Des~ript= n_l=middot0 _

AT RY-7355 R Attenuator 100 db in 10 db steps plus CAL pffi Cl Dl-505 K Cap 5mI plusmn20 100 VroDC metalized mylar C23537 L Cap 01mI G~N 500 vNDC disc ceramic

50-5456 596066 727375 767796

C3 TMT-3625 Y Cap 40-40-20mI 450-450-25V electrolyticC4a J Cap 600pI plusmn5 500 WVDC silver mica C4b 466 J Cap 80-4S0pI 175 WVDC compression mica C567 1732000333M Cap 033mI plusmn20 200 WVDC tubular mylarL

D2-105 200 WVDC metalized mylarc6 K Cap 1OmI plusmn20 200 vNDC tubular mylar1732000104MC91055 L Cap 1mI plusmn20

7478 C7 D4-224 K Cap 22mI plusmn20 400 WVDC metalized mylar

Cap 33pI 500 WVDC NPO disc ceramicC81217 OS31000COG0339C L plusmn~pI 21

Cll1520 0557051COPOIOR L Cap 15-7pI shy 350 ~NDC NPO var ceramic 24

C1625 0557051U2P034R L Cap 8-50pI 350 vVDC N750 var ceramic CIS 3192000U2P047R L Cap 9-50pI shy 350 WVDC N750 var ceramic C19 J Cap 300pI plusmn5 500 WVDC silver mica

500 vNDC tubular trimmerc26 5320013R C29 65 84c~ C3132

L J J

Cap 5-5pI shy500 WVDC silver micaCap 47pI plusmn5 500 WVDC silver micaCap 1000pI plusmn5 500 VNDC silver micaC33 J Cap 200pI +5 500 WVDC silver mica

1500 PVDC var air C34 J Cap 250pI plusmn5 C36 167-152-10 H Cap 116-202pI

350 vNDC var ceramicC404244 0557051COPOIOR Cap 15-7pI shyLJL

500 WVDC silver micaC4143 C4547b

Cap 5pI plusmn5 500 WVDC N750 disc ceramicCap 10pI plusmn5

84I~ C464888 0557051COP039R L Cap 5-25 350 WVDC NPO var ceramic

9294 C47 a Cap 150pI plusmn5 500 WVDC silver micaJ C49a 500 WVDC silver micaJ Cap 110pI plusmn5

Cap 47pI 200 WVDC N330 disc ceramicC49b~( 84e~ L C5758 J Cap 500pI plusmn5 500 WVDC silver mica C61 0801000Z5U00302PL Cap 003mI GlllV 500 WVDC disc ceramic C6264 0831000Z5UOOI02M L Cap 001mI plusmn20 500 WVDC disc ceramic

500 vNDC silver micac63 J Cap 360pI plusmn5 500 WVDC silver mica 200 ~NDC tubular mylar AR

C6S95 J Cap 68pI plusmn5 C69 Cap 035mI shy

150 WVDC electrolyticC71 Cap 4mI air 4-turn

var ceramicC8083 SPEC4197 B Cap 4 to 10pI var

0557006COP039R L Cap 5-25pI shy 350 WVDC NPOCSI 500 WVDC silver micaC82 J Cap 15pI plusmn5 200 WVDC N80 disc ceramicC84a84b

C84d~( LL

Cap 155pI plusmn5 500 WVDC NPO disc ceramicCap 100pI plusmn5

Note C47a amp b C49 amp C84

T585-p650-9FE

C49a amp b C84a - I are shown

16

on schematic as C47

bull

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

Symbol Part No Mfg Description

C87middot C91

JJ

33 pf plusmn5 500 WVDC silver mica 1000 pf plusmn2 500 vVVDC silver mica

C93 J 342 pf plusmn2 500 WVDC silver mica C97 1 0068 mf plusmn20 200 iNDC tubular mylarC98 J 10 Df 15 500 WifDC silver mica C99100101 BS28-10-15P E lOOOmf 15 WVDC electrolytic

3024-3 R Dial ratio 121D12)4 Ij277 V Diodes germaniumDS12 Type 47 Lamp (in freq tuning assy)F1 AGCl D 1 amp fuse in HKP fuse holder J1 111-102-1 H Binding post nylon red

111-103-1 H Binding post nylon black J23 12A U Jack J7 903 P fTH A Chassis connector 11 TTI-3133 W Choke 7Hy 12 3053 R Coil RF calibrate osc 13 2366-5 R Coil RF local osc 14 1500-15 X Coil RF 500 uh llQ DCR L5 3038-11 R Coil RF 290 uh 1PF 3002 R Filter 400 KC LP amp Input transformer 1S1 PM-3A G Speaker 3TI

Q Meter 0-200 DC uA 2M 46-4782-0000 S1 74A-S1 R Switch rotary 1 deck 2 pole 6 position S2 74A-S2A R Switch rotary 2 deck 3 pole 3 position S3 72A-S3 R Switch rotary 2 deck 3 pole 7 position S45 74A-S5 R Switch rotary 1 deck 3 pole 3 position C 1-4 Sic 80 Z Rectifier Ji1ico _ 5eO L2 800 PIV CR910 1N2069 Rectifier silicon 750 rna 200V

RIa Res 680Q 2W 10 carbon RIb Res 56K 1

2tT 10 carbon

R2 Res 150Q 2 10 carbon w 10 carbonR330 Res 15K

P Res 4K lOW 10 wire wound w 10 carbon

R4 R563241 C Res lOOK

43455154

Res 680S2 10 carbon Res 220QR7S36

R9 R1756

10 carbonCCC Res 820Q 10 carbon

Res 120K 10 carbonRlS53 C R196) R20 34394464 R213538

496568 R222329 R24 JF7541

ResCCC

IF

10 carbon47K Res 2K 5 carbon Res 68K 10 carbon

1 deposited carbonRes 499K 30 VARA 1316 S 10 turnRes 500Q

It S30 VARAR25 JF7542 F Res 25K R31 C Res 220K 10

Res 5K 30 VARA 38 SR3755 JF7539 FCR405052 Res 27K 10

R42AC OFF KS9156 F Res 250K 30 VARA 38 S WSPST

T585-P650-9FE 17

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

Symbol Part No Nfg Description

R46 C Res S20Q 2W 10 carbon l_WR4748 C Res 13K 5 carbonrR57 I Res 10K -N 1 deposited carbonY- JR58 rvlY1564 F Res 200~2 Z1 30 VAR A HT SD

R59 I Res 487Q VJ 1 deposited carbon R61 C Res 750Q 11 5 carbonfR62 C Res $21 10 carbon5

R66 C Res 6$K vJ 10 carbon R72 C Res 47Q 2W 10 carbon R74 C Res 100Q 1iJ 10 carbon R75 C Res 56K w 10 carbon

Tl 23 4 R8260 T 500 KC IF transformer 56

Tes TTI-3134 Vi Output transformer T9 TTI-3135 W Power transforroer 115V primary 50-60 cps V1468 66616BH6 Vacuum tube V2 6AL5 Vacuum tube V379 12AU7 Vacuum tube V5 6BJ6 Vacuum tube VIO 6AQ5 Vacuum tube VII OB2 Vacuum tube

Xl] 143K 0 Crystal 499975 SC-6 case X2 ~ 144K 0 Crystal 500025 sc-6 case

X57 105K 0 Crystal 499100 sc-6 case X6$ 106K 0 Crystal 500900 -

SC-6 case X9 107K 0 Crystal 498530 sc-6 case XI0 108K 0 Crystal 501470 sc-6 case

JA 203FIAC A Cord 3 conductor power

T585-P650-9FE 1$

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

2172 SELECTIVE VOLT~mTER

This unit is similar in outside physical appearance to a Model 2174A The frequency range and selec ivity differ as noted below The filter curves and block diagram are as given on the 2l74A brochure

Frequency range 70 cps to 6 KC on bands AB amp C 300 cps to 160 KC on bands DE amp F

Selectivity 50 - 3 KC and 10 KC

Filter bandwidth 6 db down 45 db down 60 db down (typical) 50 - 60 cps 450 cps

3 KC 3000 cps 7800 cps 10 KC 4middot00 cps 21 KC

Level full scale -68 to +32 dbm

Accuracy plusmn5 db -80 to +32 dbm 300 cps to 160 KC

Spurious response belovv 60 db

Intermodulation below 60 db

Power requirements l50V AC 5060 cps

Weight 28 pounds

Size 8-34 x lOt x 17 plus hdwe

Monitoring SSB AM FM - speaker or headset

9FD

19

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

APPENDIX A

Certain precautions are required when calibrating the Selective Voltmeter

A BE SURE to calibrate the Selective Voltmeter with CALIBRATE OSC signal (2 amp 3a below) NOT the VAR FREQ feedthrough (2 amp 3b below)

The VAR FREQ OSC feedthrough is defined as the signal from the VAR FREQ OSC passing through the crystal filter (500 KC center frequency) and indicating on the meter This feedthrough can be mis-tuned anyshywhere on the lower half of band lAl due to the 2 KC range of CAL 2 TRIM control

The following test will distinguish between CALIBRATE OSC frequency and the local oscillator feedthrough

1 Peak the meter indication of the signal present in step CAL 2 of INTERNAL CALIBRATION given on page 7flCY

2 Rotate the ATTENUATOR from CAL to +30

3a The meter pointer will drop to below -20 when the CALIBRATE OSC signal is present

3b The meter pointer will not change when the VAR FREQ OSC feedthrough is present

B Do not calibrate the Selective Voltmeter on the 3 KC or 10 KC SELECTIVITY position To use the 3 KC or 10 KC SELECTIVITY position for measuring calibrate on 50 - as given in INTERNAL CALIBRATION paragraph on page 7 Then proceed as follows~

1 Measure a frequency on D E or F bands on the 50 - SELECshyTIVITY position and note level

2 Measure the same frequency with the 3 KC or 10 KC SELECTIVITY and change the CAL 2 LEV to give the same level as measured on the 50 - SELECTIVITY

5 FF 20

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

___ I

J

C AL FIL ER

5

l I I

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60

r R

A 10

-R -= R 68K 68tlt -=

S B-A DET r osc PO ER SU PLY

54 ONITOR VI 082

Lsa ~ IU

I l

R47 13

-S [6Mft 0

~60