TM Broadcast Engineering - americanradiohistory.com...SAN FRANCISCO OFFICE The Maurice A. Kimball Co., Inc. 580 Market St., Room 400 San Francisco, California 94104 (415) 392-3365

t'ci?L A HOWARD W. SAMS PUBLICATION

TM

FEBRUARY 1968/75 cents

Broadcast Engineeringthe technical journalof the broadcast -

communications industry

MOM 1551 VINO test set

here's a new, lightweightportable video test setmars as reliablein death valley as it ison Dike's peak

Removable front cover and accessories are self -storing.

availabletest signals

10 Step Linearity

Window

Sine Window

Multiburst

Bar & Dot

featuresTemperature stable

Reliable solid state design

Modular test signal generators

Dual isolated outputs

Self -storing accessories

Easily serviced in the field

Riker's new 1551 Video Test Set has been developed specif-ically for the telephone industry to insure accurate analysisof video transmission quality and is presently in use in anumber of Bell System installations. The 1551 is lightweight,shock resistant and especially suited to field use, providingcontinuous and reliable operation over the widest possiblerange of climatic conditions.

All test signals generated by the 1551 are composite withstandard E A Sync. Dual outputs are provided at 124 ohmsbalanced and 75 ohms unbalanced allowing measurementsto be made into balanced terminal equipment and unbal-anced lines or facilities.

The plug-in design of the individual test signal modulesmakes it easy to service and maintain the test set in fieldlocations. Failure or removal of any single module will notaffect the performance of the remaining test signal genera-tors. All accessories, including a removable cover, are self -storing to prevent loss during long term use.

PRODUCTS FOR VIDEO ANALYSIS, SIMULATION & CONTROL.

RIKER VIDEO INDUSTRIES 100 PARKWAY DRIVE SOUTH HAUPPAUGE, L.I., NEW YORK 11787 (516) 543-5200

Circle Item 1 on Tech Data Card

Introducing

the most versatile

vidicon camera

ever built

Cohu's new 3200 series!

IT'S A CCTV CAMERA - completely self-con-tained. Just add a single coaxial cable to anyvideo monitor and it's ready to operate. Wanthigh resolution? Plug in one of four optionalintegrated -circuit sync generator boards for525-, 729-, 873-, or 945 -line scan patterns.

IT'S A BROADCAST CAMERA, TOO! Add a"mounts -in -minutes" 5 -inch viewfinder and theCohu 3200 is ideal for studio, education, orremote applications. An optional film chainadapter further enhances its versatility andprovides all necessary remote controls.

For prices, delivery and full details, contactCohu engineering representatives in majorcities throughout the United States and Canada.

ELECTRONICS, INCSAN DIEGO DIVISION

Box 623San Diego, California 92112Phone: 714-277-6700

February, 1968Circle Item 2 on Tech Data Card

3

publisherHoward W. Sams

publications directorJ. J. Lieland

editorWilliam E. Burke

managing editorJames M. Moore

regional editorsGeorge M. Frese, NorthwestHoward T. Head, Wash., D.C.

Robert A. Jones, Midwest

research librarianBonny Howland

production managerSusan M. Hayes

photographyPaul A. Cornelius, Jr.

circulation managerPat Osborne

advertising sales manager

Roy HenryHoward W. Sams & Co., Inc.

4300 West 62nd St.Indianapolis, Ind. 46206

(317) 291-3100regional sales managers

easternAlfred A. Menegus

Howard W. Sams & Co., Inc.3 West 57th St.

New York, N.Y. 10019(212) 688-6350

southwesternMartin Taylor

P.O. Box 22025Houston, Tex. 77027,

(713) 621-0000

advertising sales representatives

westernLOS ANGELES OFFICE

G. R. HoltzThe Maurice A. Kimball Co., Inc.

2008 West Carson St., Suites 203-204Torrance, California 90501

(213) 320-2204

SAN FRANCISCO OFFICEThe Maurice A. Kimball Co., Inc.

580 Market St., Room 400San Francisco, California 94104

(415) 392-3365

foreignLONDON W.C. 2, ENGLAND

John Ashcraft, Leicester SquareWHitehall 0525

AMSTERDAMJohn Ashcraft, Herengracht 365

Telefoon 24 09 08PARIS 5, FRANCE

John Ashcraft, 9 Rue LagrangeODeon 20-87

TOKYO, JAPANInternational Media Representatives,

Ltd., 2-4, 6-Chrome,Akasaka, Minatoku,

Tokyo, Japan

El PACopyright © 1968

by Howard W. Sams & Co., Inc.BROADCAST ENGINEERING is publishedmonthly by Howard W. Sams & Co., Inc., 4300West 62nd Street, Indianapolis, Indiana 46206.SUBSCRIPTION PRICES: U.S.A. $6.00, oneyear; $10.00, two years; $13.00, three years.Outside the U.S.A., add $1.00 per year forpostage. Single copies are 75 cents, backissues are $1.00.

the technical journal of the broadcast -communications industry

'Broadcast EngineeringVolume 10, No. 2 February, 1968

CONTENTS

Features

Digital Circuits for Broadcasters J. L. SmithThe broadcast engineer can expect to encounterdigital circuits more and more in his daily work.

This series presents basic information necessaryto understand them. Part 1 of four parts.

Dropout Compensation for High -Band Color Fred J. HodgeThis article shows how a troublesome

problem in video-tape reproductioncan be solved electronically.

A Push -Button Master Control Len SpencerOperating speed and convenience are

achieved when patch cords are replacedwith push-button switching.

Maintenance of the Directional Antenna Barry AtwoodA careful maintenance program based on

common-sense principles can minimizeproblems with the directional

antenna system.

12

19

26

30

The Two -Tower Test Robert A. Jones 38A complex array is easier to understand

when it is considered to be madeup of simpler parts.

Departments

Letters to the Editor

Washington Bulletin

News of the Industry

New Products

Integrated circuits such as these aretypical of the trend toward new

concepts in electronic design. Inbroadcasting, digital circuits soonwill be as commonplace as tuned

circuits. The series of articlesbeginning on page 12 of this issueis designed to help the broadcastengineer prepare himself to work

with tomorrow's equipment.

6

43

48

54

Engineers' Tech Data

Advertisers' Index

Classified Ads

58

60

61

Broadcast Iiinginririfing

Mobile TV Systems: TV coverage capability in a class by itself. Goes anywhere, sees everything. Whether it's two camerasor twelve, CBS Laboratories will design and produce vans for your particular needs.

Cameras for special televisionneeds. The sophisticated MinicamIll multi -purpose wireless cameramay be used at waist -level, eye -level,or periscope viewing positions.

Image Enhancers for color or mono-chrome TV cameras. Provides bothvertical and horizontal apertureequalization - plus "crispening"Made only by CBS Laboratories.

Audimax/Volumax: Provides auto-matic, hands-off audio level andmodulation control - without dis-tortion. Available in AM, FM, andFM stereo.

Tomorrow's electronics todayfrom CBS Laboratories

The greatest television program in the world is nobetter than the equipment that produces it. Andthere's no better equipment made than the equip-ment that bears the label, "CBS Laboratories".Whether it's precise automatic audio controls, tele-vision display systems, video distribution and con-trol equipment, or highly versatile mobile TV sys-tems, these Professional Products will give your pro-gramming the sound and picture quality it deserves.

And with greater profit. Reason? Not because theequipment is the least expensive. It's not. But be-cause it's the best. That means a one-time invest-ment in quality- and that's the kind that pays off.

It's good business to buy the best answers to equip-ment problems. So if you are looking for a solutionto a problem - or even if you don't think there is asolution - write or call us collect (203) 327-2000.We're on your side.

PROFESSIONAL/ PRODUCTS

CBS LABORATORIESv- v- Ire Si 1,T1' rd C.' r .t tit A DI, s,on of

Columbia Broadcasting System, Inc.

February, 1968Circle Item 3 on Tech Data Card

5

REVERBER*so UNLIMITED!

It

FAIRCHILDEVERBERTRONSI

Now with the FAIRCHILD REVERBERTRONyou can reproduce the thrilling reverberatedsounds of the Grand Canyon or the colorfulreverberation qualities inherent only in goodacoustical chambers. In addition, becausereverberated sound is apparently louder thanthe same non -reverberated signal, by utilizingthe FAIRCHILD REVERBERTON in motion pic-ture, radio and television studios you cancreate realistic sound effects and attentionholding commercials.

No longer do you need expensive reverbera-tion chambers or special "on location"recordings. The FAIRCHILD REVERBERTRONcosts less than you imagine and is availablein economy model too.

The advantages of a FAIRCHILD REVERBER-TRON in your studio are virtually unlimited forcreating wide audience appeal and impact andliterally hundreds of "ear appealing" sounds.

The next time you want to "glue" youraudience's ears to the sound you're making besure to use a FAIRCHILD REVERBERTRON!

SPECIFICATIONS OF MODEL 658A (Pictured above)The 658A is a complete solid state reverberation system with electronically controlled reverbtime adjustments up to 5 seconds; mixingcontrol for adjustment of reverberated to non -reverberated signal ratios; reverb equalizationat 2, 3, and 5 KHZ. Size: 241/2 x 19".

ECONOMY MODEL 6586ALSO AVAILABLECompact, reverberationsystem for the 'big' soundin a small space. Con-tains reverb equalizationin mid and low frequen-cy range; level control;sold state design. Size:Only 51/4 x 3 x 10" deep.

Write to FAIRCHILD - the pacemaker in pro-fessional audio products - for complete details

*AIR CH I LRECORDING EQUIPMENT CORPORATION10-40 45th Ave., Long Island City .1. N. Y

LETTERS TO THE EDITORMEI MO Ell I= =11

DEAR EDITOR:I look forward to receiving every

issue of BROADCAST ENGINEERING.Keeping a file of back issues is likehaving a textbook of engineeringpractice.

Referring to the June 1966 issue,in which Thomas R. Haskett dis-cussed the small -budget audio -proofpackage, I have put together theexact package that he described. Ihave one question about the RF de-tection box: What type of antennashould be used? I connected the unitto the modulation -monitor RF con-nection and found it worked; how-ever, I'm afraid of burning out theIN34 diode. I'd also like to knowwhat to do if too much distortion isfound within this unit.

One modification that could bemade in the input matching box is amore complex switching arrange-ment. I added positions for 333ohms, 500/600 ohms grounded cen-ter tap, 250 ohms grounded centertap, and load (no audio) for eachresistor. Although these positionsmay not be used as much as others,they add convenience for the engi-neer as he searches for the mostdesirable adjustments.

I have run into a couple of prob-lems while running proofs whenconsiderable RF was present; thismakes distortion readings difficult toobtain. Good grounding cannot beoveremphasized. I made someground cable compatible with thefive -way connectors on the equip-ment. Also it is good to have variouscables with banana plugs, alligatorclips, microphone plugs, and what-ever else might be encountered. Onecan spend useless hours making up"compromise connectors."

PAUL SCHUETTStation EngineerKWG, Stockton, Cal.

Author Haskett answers Mr.Schuett's questions regarding the RFbox as follows. Ed.

Present HD meters require 0.1 to0.8 volt of audio input, so the de-tector box must furnish that muchoutput. The amount of RF inputneeded for the detector box may befrom 5 to 10 volts rms. You caneasily determine whether you havesufficient RF by the following meth-od: Connect the detector output to

the HD -meter input. Set the HDmeter to "Set Level" and turn theSET LEVEL control wide open. (Thisapplies to the Heath IM -12; performthe equivalent for other HD meters.)Couple tone -modulated RF into thedetector box until you see deflectionon the HD meter. Back off the SETLEVEL control, and increase the RFinput to the box until you have acomfortable margin of input to theHD meter.

You can couple RF into the boxfrom the modulation -monitor outputon your transmitter, as you found.The usual 1 -kw transmitter has amodulation -monitor output of about10-15 volts of rms RF, whichshould do.

Another way to get RF to the boxis as follows: Make up 4 or 5 turnsof hookup wire (insulated) into acoil about the size of one turn on thefinal plate tank coil on your trans-mitter. Tape this coil next to thetank, and connect the wire ends tothe box input through shielded line-as shown in Fig. 4, page 18 of theJune 1966 issue. For less RF, turnor move the pickup coil away fromthe plate tank. For more RF, in-crease the number of turns in thecoil. Continue adjusting until youhave enough audio at the HD meter.

If you intend using the box at apoint remote from the transmitter,you'll have to use an RF preamp de-livering about 10 volts across 75ohms, which is more or less stand-ard. The box requires so much RFthat I prefer speaking of a "pickuploop" rather than an "antenna."

The 1N34 and IN34A diodes havePIV's of 60 and 75 volts, respective-ly. This means they will break downif you put more than 42 or 53 volts,respectively, of rms RF across them.Thus, when 10-15 volts of rms RFis used, the diode should be safe.

I don't think you'll find much dis-tortion in the box, as it's a passivecircuit. Check it by comparison withyour modulation monitor. Run a dis-tortion curve on each using 1000 -Hz, 50% modulation. Rated resid-ual harmonic distortion of monitorsis typically 0.1 to 0.5%. If you dofind distortion in the box, try a newdiode (use a IN34A) and a newelectrolytic.

THOMAS R. HASKETT

Circle Rein 4 on Tech Data Card

6BROADCAST ENGINEERING

coast -to -Nast;

the switch istoWARD

snitchers! !!

rat I Lvi :J

H - *

. . . the choice of the skeptics, whose proof is performance!

Ward Electronic's all solid-state verticalinterval switchers are years ahead. Hardto believe? Once you've checked thefeatures and compared the performanceof our switchers, you'll understand whyso many major TV stations are switchingto, and with Ward.

Here are only a few of the many fea-tures you will find of special interest inour Studio, Master Control and RoutingSwitc hers. Automatic Composite / Non Composite InputHandling Capability Sync sensing, automatic sync adding andclamping on each input

Spare 75 ohm clamped output from each input

Two Independently Equalized Outputs per buss

Additive / Non Additive solid state mixingamplifier Automatic Direct take when attempting to mixnon synchronous sources

Each buss self-contained with individual powersupply, trigger pulse generator, latch and tallycircuits Transient -less vertical interval switching

Low Impedance, transmission line type inputbuss

* Write for a list of the TV stations that haveswitched to Ward, . . . and complete switcherspecifications.

WARD ELECTRONIC INDUSTRIES142 CENTRAL AVE., CLARK, NEW JERSEY 07066 (201) 382-3700


February, 1968 7

Now, from a single source,a full range of TV studioengineering services.Studio engineers seeking thebest in TV broadcasting tech-nology rely on Federal ElectricCorporation's full range ofstudio services, backed by theexperience, skill and resourcesof ITT, world leader in com-munications research andengineering.

Federal Electric offers studiodesign, installation,and backupmaintenance,custom-tailoredto improve your studio's effi-

ciency and flexibility. Result:your station equipment iscurrent, competitive and profit -making.

We design systems, select,install, tuneup and checkoutequipment, and deliver as -installed records and technicalmanuals. Whether you arebuilding a station from theground up ... adding remotepickup ... converting frommonochrome to color . .. or

merely adding updated orexpanded recording facilities,you'll find that service fromFederal Electric brings youtop professional people, fullymatured in TV studioengineering.

ITT's Service Associate,Federal Electric Corporation,621 Industrial Avenue,Paramus, N. J. 07652.(201) 967-2554

ITT8

Circle Item 6 on Tech Data CardBROADCAST ENGINEERING

Vital News in

Switching!

First new concept

in Switching in a

decade is here

Li.L.LLL-Lia_LLILLLLLIJ

._LLLU_LLLLU=LLLLU

Vital Industries, Inc. has taken the custom cost and complications out of custom switching.A unique combination of mechanical and electrical packaging has yielded exceptionally highperformance and specifications in the VIX-108 vertical interval switching system.

FEATURES:

All solid state with integrated circuits including crosspointsand control circuits.

Complete basic package 18 in by 6 out system complete withpower supply control circuitry, in 51/4" rack space. UHFConnectors.

Production or routing switcher. Any size.

Vertical interval or random switch in less than 0.1 micro-second.

Auto sync add for comp/non comp operation. Auto inhibitnon synchronous mix.

Custom built with any kind of control buttons or panels. Allstate of the art accessories also furnished by Vital Indus-tries, Inc.

GOOD ENGINEERING IS VITAL

SPECIFICATIONS for one typical 18 in 6 out system:

Exceptional isolation between crosspoints . . . 65 DB downat 4 Mhz.

Differential phase through the system . . . Less than 0.1degree at 1 volt output.

Differential gain . . . less than 0.1 percent at 1 volt output.

Frequency response . . . Flat within 0.1 db from 10 Hz to10 Mhz under all corditions.

Tilt ... Less than 0.5% over 1 field.

K factor less than 1%.

Selecting the right switcher is Vital

Write for complete information and specifications.

3614 SOUTHWEST ARCHER ROADGAINESVILLE. FLORIDA 32601 - PHONE 1904) 378-1581VITAL INDUSTRIES, INC.

February, 1968


9

When engineers get together,the conversation turns to pickups.

PHOTOGRAPHED BY FRANZ EDSON AT THE CAPITOL TOWER, HOLLYWOOD.

It's an irresistible topic.Especially since Stanton came out with the Model 500 stereo cartridge.That's an engineer's pickup, if there ever was one.Beautiful curve-within 1 db from 20 to 10,000 Hz, 2 db from 10,000 to 20,000 Hz.Fantastically small moving system to trace the wildest twists in the groove.Light weight (only 5 grams!) to take advantage of low -mass tone arms.And, of course, Stanton's legendary quality control.No wonder engineers use the Stanton 500 for critical broadcastingand auditioning applications.And to impress other engineers with their pickupmanship.(Available with 0.7 or 0.5 -mil diamond, $30; with elliptical diamond, $35.For free literature, write to Stanton Magnetics, Inc., Plainview, N.Y.)


NOWGATES MONITORS GATESThree new solid-state FM monitors from Gates . . . supplier ofthe most complete line of FM broadcast equipment from asingle -source manufacturer. From microphone to antenna, andeverything in-between.

Advanced modular design of our monaural monitor permitsconversion for stereo, a bonus feature for monaural users. Spaceprogram integrated circuits add to Gates reliability. And, ofcourse, they can be used to monitor whatever brand of FMtransmitting equipment you have.

Available from stock, our new solid-state FM monitors arefully FCC approved and thoroughly field tested. So check withGates first - your single source for all FM broadcast equipment.

GTM-88S FM Stereo Modulation MonitorIntegrated circuits for greater dependability. Full pro-vision for adding SCA adapter. All controls accessiblefrom front panel. Silicon solid-state circuitry.

GTM-88M IFM Monaural Modulation MonitorConvertible to stereo operation. Provision for adaptingto SCA operation. Integrated circuits for highest relia-bility. All controls accessible from front panel. Siliconsolid-state circuitry.

GTM-88F FM Frequency MonitorWide -band pulse counting detector. No tuned circuitsin pulse detector. All controls on front panel. Fullytemperature compensated. Silicon solid-state circuitry.

GATES INTERTYPEION

GATES RADIO COMPANYQUINCY, ILLINOIS 62301, U.S.A.A subsidiary of Harris-Intertype Corporation


February, 1968 11

DIGITAL CIRCUITS

FOR BROADCASTERS

Part 1 of four parts.

by J. L. Smith*

Digital circuits soon will be commonplace in broadcasting;here is basic information you will need to understand them.

Until recently, digital circuitshave not had significant use in theaverage broadcast station. However,modern advances in techniques andprocesses have resulted in equip-ment employing digital circuits, andthese circuits are providing not onlyadded functional capability but alsoincreased reliability. Digital circuitsnaturally fill the requirements forvarious types of signaling circuits,frequency monitors, modulationmonitors, parameter monitors, andcontrol circuits of many descriptions.The broadcast engineer should be-come familiar with these digital cir-cuits so that he can utilize theadvantages they offer.

Digital circuits possess several ad-vantages over their analog counter-parts. Probably the foremost is in-creased reliability, which resultsfrom the fact that in most digital cir-cuits the transistors operate in ei-ther a saturated mode or a cut-offmode. Variations in transistorparameters have minimum effect onthe operation of the circuits whenthe transistors are operated only inthese two minimum-power-dissipa-

"Manager, Broadcast Systems Engineering,Collins Radio Co.

tion modes. Further reliability isachieved by virtue of the fact that,generally speaking, it is easier todetect which of two widely separat-ed states exists in a circuit than it isto detect how much of a signal ispresent.

Additional advantages offered bydigital circuits lie in their ability tobe connected as logic circuits andto perform decision functions. Logiccircuits composed of AND gates andOR gates can instantly and consis-tently perform operations deter-mined by programmed logic. Theycan address a certain operation, is-sue a command, and interrogate areply.

Although the logic diagram ofsome digital equipment appearscomplicated to those not familiarwith such circuits, the maintenanceof the equipment is simplified be-cause the circuits are operating inonly two modes, on or off. Thecliche, "Digital circuits either workor they don't work," approachesfact. The transistors in digital cir-cuits are used as voltage -controlledswitches. They either permit a volt-age level to be present or they pre-vent it. It is these voltage levels that

1 0 7 25

I 5 X 102= .05

2 X 101

= .20

7 X 100= 7.00

0 X 101= 00.00

1 X 102= 100.00

SUM = 107.25

constitute the signal, and these levelsperform the function that the equip-ment was meant to perform. Thisseries of articles will present thebasic fundamentals of logic anddigital circuits. The reader will ob-tain an introduction to the subjectsufficient to allow an understandingof such circuits, and, if he chooses,he may utilize this understandingin more advanced studies.

Binary Numbers

Binary numbers play an impor-tant role in digital circuits, so it isadvantageous to discuss this numbersystem briefly. Basically, the samerules which apply to decimal num-bers also apply to binary numbers.The main difference is that the deci-mal system is based on a radix of10; that is, it uses ten digits, 0through 9, to make up the system.The binary system employs a radixof 2 and utilizes only two digits,0 and 1. Any other digit has nomeaning in the binary system.

A comparison of the constructionof numbers makes the two systemseasily understood. The decimal num-ber 107.25 is, in reality, the sum offive numbers. The value of thesenumbers is determined by a partic-ular digit and the position of thatdigit. Starting with the decimal point,each digit is weighted by a powerof 10 that starts with 100 at the leftof the decimal point and increasesto the left by a power of 10 for eachposition. To the right of the decimalpoint, the powers of 10 decrease by1 for each digital position. In effect,the digits which compose a decimalnumber indicate how many units,how many tens, how many hun-dreds, etc., must be added togetherto form the number. Fig. 1 illus-trates the numerical construction ofthe number 107.25.

A binary number has a similarconstruction, except that the weightsput on the positions are powers of2 and it is only possible to indicate,

Fig. 1. Decimal number is the sum ofits digits weighted by powers of 10.

12 BROADCAST ENGINEERING

by a 0 or 1, that a certain power of2 is included or is not included. Thepowers of 2 start with 2° at theleft of the binary point' and increaseby 1 for each position to the left.They decrease by 1 for each positionto the right. Fig. 2 illustrates the bi-nary construction of the same num-ber used in Fig. 1.

The decimal number 107.25 iswritten in binary form as 1101011.-01. At first glance it may appear thatthe large number of digits necessaryfor the binary representation is adisadvantage in terms of the elec-tronic circuitry necessary to storeand handle these digits. In fact, how-ever, the required circuitry is actual-ly less than for the decimal counter-part. This is because it is only nec-essary to register either 0 or 1 foreach digital position in the binarysystem, whereas the decimal systemrequires that each digital positionregister 0 through 9. Thus the ninebinary digits require nine two -statedevices, or a total of 18 states for thesample number in Fig. 2. The fivedecimal digits of the correspondingsample number in Fig. 1 requirefive ten -state devices, or a total of50 states. This, plus the fact thattwo -state devices occur so natural-ly, forms the foundation for the useof the binary system in digital cir-cuits.

Decimal/Binary Conversions

Binary numbers are converted todecimal numbers simply by addingthe weighted digits as in Fig. 2.

1 The decimal system uses a decimal point, butthe binary system uses a binary point.

Decimal numbers are convertedto binary numbers in two steps. Thedecimal number is separated at thedecimal point. That portion to theleft of the decimal is converted bya process of division and that to theright of the decimal is convertedby a process of multiplication. Thefinal result is the combination of thetwo.

Consider the conversion to binarynotation of the decimal number26.625. The portion to the left ofthe decimal (26) is successively di-vided by two, with the remaindersnoted in a column to the right. Theremainders are then weighted start-ing with 2° at the top and increas-ing downward by a power of 2 foreach remainder. The process is car-ried out as follows:

222

Remainders WeightingFactor

2 13 0 2'

2) 2'

211 0 2'

2'

0 2'

The binary equivalent of thenumber 26 is then 1 1 0 1 0. Thisbinary number is made up of theremainders placed in sequence withthe bottom digit being placed onthe left.

The fractional number (.625) isconverted by successively multiply-ing the fraction by 2 and noting the"spill -over," i.e., that which resultsto the left of the decimal. The spill-over is not multiplied in succeedingsteps.

Fig. 2. A binary number is the sum ofits digits weighted by powers of 2.

Weighting Factor

2-'

2-2

2-'

Spill -Over

.625X2

1 .250x2

0 .500

x2

1 .000

Thus the binary equivalent of0.625 is 0.101, which is written bycollecting the spill-overs in se-quence with the top spill -over onthe left.

Then the total number 26.625 iswritten in binary form as the sumof the whole and fractional parts:

26.625 11010.101

Binary Arithmetic

The four basic arithmetical op-erations can be performed withbinary numbers just as they can beperformed with decimal numbers.Table 1 gives the rules for each op-eration. These rules are identicalwith those of decimal arithmetic,even though this fact may not bereadily apparent because the radix2 is not familiar to most of us.

Example 1. Add the binary equiv-alents of the decimal numbers 7,6, and 3.

Sum

7->6->3->

7->

11 }Carries111

111110011

10000

As shown in Table 1, 1 + 1 = 0with 1 to carry. Each time a carry isgenerated, it is placed above thenext column to the left and includ-

1 0 1 0 1 1 0

1 X 22= . 25

I X 2-1= . 00

1 X 20= 1.00

1 X 21= 2.00

0 X 22= 0.00

1 X 23= 8.00

0 X 24= 0.00

1 X 25= 32.00

1 X 26= 64.00

SUM = 107.25

February, 196813

DL VICE - 4-

DEVICE

1 MSEC

(A) Three bits generated by device

To

(B) Level generated by device

ed in the sum of that column. Iftwo or more carries are generated,then each is included above the col-umn to the left. In the exampleshown, the right column generatedone carry. The next column to theleft generated two carries, which inturn generated two additional car-ries. The binary sum resulted as10000, or 16.

Example 2. Subtract the binaryequivalent of 6 from the binaryequivalent of 9.

9->-6-->3-*

01 Borrows

1001

110

0011

Although subtraction is not ex-tremely difficult, it is the most com-plicated of the four binary opera-tions. The steps are identical withthose of decimal subtraction, exceptthat the unfamiliar radix makes theborrow process somewhat vexing.Borrowing is easy by the followingrule:

0 - 1 =1 and borrow 1. To ac-complish the borrow, reverse eachdigit in the minuend to the leftof the borrow, until a 1 is changedto a 0. Register these changesin a row above the minuend anduse the uppermost row as a newminuend.

Table 1. Rules of Binary Arithmetic

Addition Subtraction

0+0=0 1-1=00+1=1 1-0=11+0=1 0-0=01+1=0 & Carry 1 0-1=1 & Borrow 1

Multiplication Division

1X1=11x0=0Ox1=0Ox0=0

1+1=10+1=00+0=0

6V

OV

6V

-0V

Fig. 3. Bits and levels are distinguished by duration.

In the example shown, the sec-ond column from the right requireda borrow from its left neighbor. Thisborrow in turn resulted in a borrowfrom the extreme left column. Theseborrows were registered above theminuend and became the new minu-end.

Example 3. Multiply the binaryequivalents of 3 and 4.

4-* 100x3-> 011

12 100

100

000

01100

Multiplication is the most simpleof the operations. It is carried outin a manner identical with decimalmultiplication, but is simplified bythe fact that it is only necessary tomultiply by either 0 or 1. The par-tial products are added in accor-dance with the rules of binaryaddition.

Example 4. Divide the binaryequivalent of 18 by the binaryequivalent of 3.

6 110

377 011) 101211018 011

-0 011011

00

Division is carried out in theconventional manner, but it, too,is simplified because it is only nec-essary to indicate in the quotientwhether or not the divisor will gointo the dividend. If it will, a 1 isshown in the quotient. If it will not,a 0 is shown and another digitbrought down. Binary subtractionis performed in the intermediatesteps (with the borrows carried outmentally in the example).

Digital Data

The binary 1 and 0 are repre-sented in digital circuits by voltagelevels. It is common to let zero voltsrepresent logic 0 and a voltagevalue, e.g., + 6 volts, represent logic1. The logic levels are a matter ofdefinition, however, and any con-sistent scheme may be used. Themanipulation of these voltage levelsconstitutes the digital logic opera-tions. In practice, the logic levelsare not precisely 0 or 6 volts, butmay vary slightly about these points.For example, logic 0 may not beprecisely 0 volts because it may beformed by a shunting transistorwhich has a finite saturation voltageamounting to a few tenths of avolt. By the same token, there canbe variations in the logic -1 level.The circuits are designed to accom-modate these variations, however.

Both logic -1 and logic -0 levelsmay also be subjected to variationsdue to transient spikes or stray ACpickup. All of the variations in thelogic levels, regardless of the natureor origin, are considered logic noiseand must be considered in the de-sign and maintenance of digitalequipment. A noise spike riding onlogic 0 can be confused for a logic1 if the spike is large enough. For-tunately, the logic levels are sep-arated widely enough that the noiselevels encountered are not signifi-cant in most cases. One must befamiliar with the fact that logicnoise exists, however, so that noisewill be recognized should it be en-countered.

A binary digit is called a bit (Bi-nary digIT). The binary number11011 is made up of five bits.Likewise, voltage levels making up


New E -V Model 668 Dynamic

Card old Boom Microphone

with built-in

programming panel!

C)It's just like having 36 micro-e phones in one, at the end of your

boom . Simply match the computer-style-programming pins to the color -codedack feld inside the new E -V668. You'llget any combination of flat response

:40 tc 12,000 cps), bass and/or treblenalloff treble rise, and 80 or 8,000 cpscutoff_ The 668 built-in passive equalizermatches response to need precisely with-Dut loss in output level-mixes perfectlywith any other microphone.

The 368 cardioid pattern is symmetricalin every plane with excellen: rear cancel-lation At every program setting. Two inde-pendent Continuously Variable-D*systemsprovice this uniformity, yet permit highoutpu- (-51 dbm) for distant pickupwithout added equipment or special cables.

Light in weight and small in size, the568 with integral AcoustifeamTM wind-screenand shock mount minimizes shadowproblems while allowing noise -free fastpanning, indoors and out. Its 1 lb., 11 oz.weight eliminates "fishpole fatigue" andcounterbalancing problems.

The 368 is guaranteed UNCONDITION-ALLY against malfunction of any kind-even i caused by accident or abuse-for:wo years. And, like all E -V Professionalmicrophones, it's guaranteed for lifeagainst failure of materials or workman-ship.

The EA/ 668 is the result of a three yearlntensve field testing program in movieand Tv studios from coast tc coast. It hasproved itself superior to every other boommicrophone available. Find out why witha no cc st, no obligation trial in your studio.Call your E -V Professional microphonedistributor today, or write us direct forcomplete specifications.*JEW! MC DEL 667A Identical to Model 668 except sharp cutoffliters anc HF-rollotf eliminated. List price: Model 667A,$345.00;viodel 665, $495.00 (less normal trade discounts).

Patent Jo. 3115207 covers the exclusive E -V

ELECTRO-VOICE, INC., Dept, 281Vo Cecil Street, Buchanan, Michigan 49107

gkerirraCZ,

SETTING NEW STANDARDS IN SOUND

Ci-cle Item 38 on Tech Datc Card

The Norelco "Little Shaverdoes everything its big brother,the PC -70, can do...and gets around a lot more.This is the new NorelcoPCP -70 Portable Color Tele-vision Camera. We call it the

"Little Shaver" for short.Like its big brother, the

PC -70, which is used on themajority of top network live

and taped shows, it employsthe exclusive Norelco 3-Plumbicon* tube systemthat provides the truestcolor, highest resolutionand maximum sensitivityavailable today.

The "Little Shaver"goes where the action is.

Sports. News and documen-taries. Political events . . .

just about anywhere a mancan go.

The "Little Shaver" isfully compatible with thecamera control unit of thePC -70 studio camera. Thus,present PC -70 owners havean even greater advantagein that they can have the ver-satility of the PCP -70 with

no further expense for con-trol equipment.

Instantly accepted byall the major networks, theNorelco PCP -70 is the port-able that gives you the

world's best color televisionpicture.

If you want faithfulcolor reproduction in a port-

able camera, you want the"Lithe Shaver." For a livedemonstration and techni-cal data, call or write ourrepresentative, Visual Elec-tronics.

*Registered trade mark for television camera tubes.

NorelcoPHILIPS BROADCAST

EQUIPMENT CORP.

February, 1968


299 Route 17, Paramus, N.J. 07652 201/262-7300

17

DEVICE

(A) Serial data 11011

DEVICE

(B) Parallel data 11011

the binary 1 and 0 are called bitsif they have a time duration that isrelatively short and controlled bythe equipment. For example, if aswitch is thrown in a circuit andfrom the circuit emerges a + 6 -voltpulse of, say, 1-msec duration, then1 bit has been generated. If, how-ever, when the switch is thrown + 6volts appears and remains until theswitch is opened, then a level, nota bit, has been generated. See Fig.3 for a pictorial display of this con-cept.

DEVICE

-

0

Fig. 4. Data may be transmitted serially or in parallel.

A collection of bits which haveassigned meanings is called digitaldata. The number of bits generatedor handled per second is called thebit rate. This is a measure of howrapidly equipment can process digi-tal data.

Digital data exist in two forms,serial and parallel (Fig. 4). Serialdata consist of bits which occur ina time sequence on a single conduc-tor. The first bit is present for agiven length of time; then it goesaway and the second bit appears.

do

..

-t-*z.)

e n,ni/e.

Fig. 5. Words consisting of parallel bits may be presented serially in time.

The second goes away and the thirdappears. This continues with thecomplete data appearing at a singlepoint serially in time. For paralleldata, a separate conductor existsfor each bit, and all bits appearsimultaneously. It is evident thatgreater speed is possible with paral-lel data than with serial data, be-cause all the parallel data are pre-sented in the amount of time re-quired to present a single bit in theserial form. The price that must bepaid for this speed is the fact thatmore complex equipment is requiredto handle all bits at once, whereasthe equipment can be shared whendata are in the serial form.

The data bits frequently are as-sociated in groups of special mean-ing. These groups are called words.Suppose a device were used to sendthe five -bit equivalent of a series ofdecimal numbers. Then perhaps thefive bits comprising a single num-ber are designated a word. As aresult, the processing of the datacan be handled by words, i.e.,groups of five bits. It is also pos-sible to handle a word as paralleldata and handle a group of wordsin serial fashion. Such a scheme iscalled serial/parallel data handlingbecause both serial and parallel dataare present (Fig. 5). These datamay represent the input to a com-puter where the words representbinary numbers to be added.

Next month, the second part ofthis series will examine the logicelements which form the basis ofdigital circuits. A


DROPOUT COMPENSATION

FOR HIGH -BAND COLOR

-Some of the problems, andtheir solutions, in compensating dropcuts incolor video tape are explained.

by Fred J. Hodge"

The 1965-66 television seasonwas a turning point for color. Tech-nological advances, plus a large in-crease in the number of viewers,caused a shift in program emphasisfrom compatible monochrome tohigh -quality color transmission. Pri-or to 1965, nearly all scenes telecastin color or black -and -white featuredpicture composition in which theprimary brightness stimulus w ascaused by the luminance portionof the picture. Consequently, re-dundant luminance dropout com-pensation had been a satisfactorysolution to the video-tape dropoutproblem. This situation changedwhen attention shifted to the coloraudience. Higher -saturation colorsystems became popular, and it wasapparent that full -color replace-ment would be required for ade-quate dropout protection.

Physical Nature of Dropouts

The discussion of full -color sub-stitution starts properly with ananalysis of what a dropout actuallyis. When a particle in the video-tape coating interferes with head -to -tape contact (1), or a voidexists in the oxide due to a scratch,a reduction in the recorded or re-produced signal can be caused.(2). As a result, the normally con-stant FM signal used for video re-cording becomes amplitude modu-lated to a degree which depends onthe signal loss produced by theparticle or scratch. When this de-gree of amplitude modulation can-not be accommodated by theplayback limiter circuits of a re-corder, a momentary streak ap-pears in the reproduced picture.

Most dropouts caused byscratches result from handling atthe user level and produce diago-nally organized groups on the tele-vision screen. Multiple -generationtape copies contain defects origi-

February, 1968

Video Project Supervisor, Mincom Div.,3M Co., Camarillo, Calif.

19

nated in previous recordings andthus multiply the incidence of visi-ble dropouts.

High -band recording, by its verynature, increases the incidence ofdropouts over that for low -bandoperation. Over half of the record-ed energy is in the first 1/10wavelength of penetration into therecording medium. Since the wave-length is shorter in high -band re-cording, the energy is closer to thesurface of the tape, and thereforethe recording is more susceptibleto the surface contamination effectswhich produce dropout (3).

Dropout streaks in a reproducedpicture may be either light or dark,or any color, depending on theexact transient nature of the videosignal as well as other instanta-neous machine factors. Futhermore,should defects occur during theperiod of video clamping or colorburst, polarity of the resulting ef-fect becomes unpredictable.

In general, dropouts are mostannoying when they appear asbright streaks on a predominantlydark or low-key background. Itshould be kept in mind that moredefects may be apparent to theviewer's eye as picture compositionvaries, even though tape qualityand machine constants remain un-changed.

Effect of Head Penetration

Manufacturer's tests indicate thatvideo tapes exhibit fewer dropoutsat the higher head -to -tape contactpressures secured by deeper pene-tration. Also, and within limits, thesehigher penetrations have a greatertendency to remove certain offendingparticles in or on the surface of thetape.

With some brands of tape, definiteimprovement from a dropout stand-point usually results after a tape hasbeen preconditioned through severalpasses with deeper head penetra-tions. Most defects which remaindespite initial head passes still pro-duce visible dropouts in a degreerelated to head penetration.

As a matter of operating practice,tapes must be recorded so that"skew" and "scallop" patterns in theindividual head bands remain com-plementary even when tape is splicedonto stock recorded with headshaving different head projections.This requires that the degree of ac-

tual penetration of the heads intothe tape surface be different fordifferent head projections; the pene-tration should be reduced approxi-mately 1 mil for each change of 1mil in average head projection.Therefore, as heads gradually wearfrom, for example a 3 -mil to a 1 -mil projection, the penetration intothe center of the tape would under-go a reduction of about 2 mils whenthe female guide is adjusted for mini-mum "skew" and "scallop."

Inasmuch as shallower head pene-tration results in less intimate con-tact in a potential tape -defect area,it is to be expected that higher drop-out counts will occur with wornheads during both record and play-back modes. Even if a disturbingparticle is removed by the headsduring the recording pass, the dis-turbed magnetic pattern remains andaffects reproduction during ensuingplaybacks. Future recordings, how-ever, may show few or no defects inthe particular area.

Electrical Nature of Dropouts

A signal dropout in a video re-cording system consists of anabrupt negative amplitude -modulat-ed notch in the carrier. The effective-ness of limiter circuitry in thedemodulator can have markedeffects on how clearly this AM com-ponent is reproduced through theFM system.

An examination of the playbackcarrier prior to its introduction intothe limiter stages discloses that, withmost samples of tape, the signal con-tains an entire family of dropouts ofdifferent amplitudes and durations(2). The change in amplitude of thecarrier during these momentaryevents may range from a reductionof only a few percent to a completefailure. A majority of these dropoutsare never seen, as their effects areabsorbed by the action of the limit-ers in the demodulator chassis.

Head wear or circuit changes cancause partial loss of total limitinggain. If this occurs, an increasingnumber of the carrier depressionsreach the discriminator and becomevisible on the television screen.Furthermore, improper transient re-sponse in the RF amplifying systemcan exaggerate the durations andamplitudes of the carrier dropouts,making their effects more pro-nounced.

Excessive noise also can reducedropout immunity, since the carriercannot be recovered by the limiterwhen momentarily reduced to avalue less than the noise level.

Psychophysical Factors

Several psychophysical attributesof human perception enter into whatviewers think they see on the tele-vision screen. It is well to reviewthese to gain better insight into whatcan be done to understand and im-plement compensator action.

In the normal process of visualperception, the viewer is engaged ina whole -perceiving attitude, as op-posed to a part -isolating attitude;that is, he is concerned primarilywith the total image (4). The phe-nomenon of figural persistence-thetendency of the observer to carryover the same figure and back-ground organization of an image-was discovered early in twen-tieth-century psychophysical studies(5). Perceptions of figures are or-ganized along certain principles (6).These include:1. Nearness - Dots close together

will be seen as a group.2. Sameness - Dots of the same

color or shape will be seen asa group.

3. Common Fate - Dots whichmove simultaneously in the samedirection will be seen as a group.

4. Good Continuation and GoodFigure -A nearly complete cir-cle will be seen as a circle. Asweeping smooth line with abump on it gives the viewer analmost irrepressible desire tosmooth the bump.

Use of Redundant Signal

Early in 1960, the principle of re-dundancy was applied to a standardvideo recorder system to compensatefor the visual effects of signal drop-outs. In this system, an artificial andessentially redundant signal was ob-tained through a delay line of requi-site signal characteristics and a timedelay corresponding to one televisionline (approximately 63.5 microsec-onds) . This selection was based onthe following factors:1. The inherently high redundancy

existing between signal profilesin most time -adjacent line pe-riods (two successive lines asdisplayed on a kinescope screen)comprising a television signal.


2. General inability to detect minorgeometric distortions of pictorialdetail which exist for short timedurations.

3. The increasing availability ofeconomically feasible delay de-vices of requisite bandwidthsand duration.

Ideally, the one -line delay systemfor compensator use should retardthe television signal 63.5 microsec-onds (63.55 microseconds forcolor) and display a conventionalvideo frequency response and risetime. A full -bandwidth system wasdeveloped and evaluated, but untilthe new generation of high -bandcolor video tape recorders becamepopular, a 63.5 -microsecond delayline with a frequency response of500 kHz was used to store the highlyredundant components of the videoand sync signals.

Although the bandwidth of the re-placement signal was less than thatrequired to pass burst and colorinformation, the system was com-patible with color operation. Theviewer could not perceive the lackof color in the dropout area if thebrightness information providedwas similar to the surrounding scene(7), so long as the color saturationwas relatively low. Low -band colorrecorders were not capable of highlysaturated color operation.

Another factor which helped wasthat these early color television re-corders employed the heterodynecolor -recovery system. In this sys-tem, the phase jitter in the chromi-nance and color -burst signals waseliminated by separating the chromi-nance and burst information fromthe video, and then developing acorrection signal from the tape burstfor use in cancelling the chromi-nance phase jitter. The heterodynecolor system was tolerant of missingburst pulse and other dropout ef-fects. It had the disandvantages oflimiting the luminance bandwidthand of not removing the positionaljitter from the synchronizing signal.The direct color -recovery systemwas developed to solve these prob-lems.

In direct color recovery, line -by-line sampling of tape sync and color -burst phase is used to controlelectrically variable delay linesthrough which the entire signal ispassed. In this way, time -base jitteris removed from the video andchrominance information.

The complete story on our broadcast

COMMIE COMMIS and

capability...no charge!

Why mg write tor your copy Man

Coaxial Cable Air dielectric andfoam dielectric types offer reliabil-ity and lower loss characteristics.

Connectors Type N, HN, UHF,TNC, LC, EIA, splices and endseals. From stock delivery.

Coaxial Cable Accessories Off -the -shelf delivery of cable grips,grounding kits, tubing cutters, two -stage regulators, automatic dehy-drators.

Rigid Line Available in four diam-eters. Meets or exceeds EIA RS225specifications.

Rigid Line Accessories Miter el-bows, gas barriers, reducers, teeassemblies, adapters, flanges areavailable.

Supporting Hardware Anchor fit-tings, hangers, braces, supports,clamps, bulkhead fittings.

PHELPS DODGE ENOLERTCHTRHAO:ENIC CPO ICC:1ST

February, 1968


21

Direct color recovery is not toler-ant of dropout; even one missingcolor burst or sync pulse producesan annoying flash in the picture dis-play. Furthermore, there is nowgreat popularity of high -band colorrecording and of receivers capableof producing more vivid colors. Al-though before the 1965-66 seasonreplacement of only the redundantluminance considerably improved alltelevision tape recordings, at presentthere are problems with less -than -correct color -dropout compensation,particularly in cases of high satura-tion (9).

The constant -luminance principleis the basis for redundant -luminancedropout compensation. Unfortunate-ly, constant luminance is not valid athigh saturation, and because of this,the subcarrier information affects thepicture brightness. Thus, dropout-substitution material which replacesonly redundant luminance or incor-rect color information can substitutewrong color and intensity values inthe high -saturation areas.

A second problem occurs when asaturated color appears with reducedluminance level. In these scenes, re-dundant -luminance dropout com-pensation appears black.

Trouble is also present whenmonitor or receiver convergence isconsiderably less than perfect (notunusual near the edges of the ras-ter.) A dropout replacement of onlyluminance poses the same problemas edge information in the picture,since it represents a color discontin-uity. The result is wrong color orintensity replacement.

Full color replacement does nothave these problems. The solutionto the dropout problem, therefore, isto provide full -color dropout substi-tution.

Full -Color Compensation

Before discussing full -color repair,it is necessary to consider the re-quired accuracy of the information.Visual tests have shown that even aslight color -hue error in substituteinformation is actually more objec-tionable than no color at all. Thesetests indicate that correct luminancecompensation is still superior towrong -color compensation, especial-ly in the primary colors.

To obtain accurate color replace-ment information, it is necessary toovercome three basic problems:

(1.) Time -base stability of 4° phase,or about three nanoseconds. (2.)Differential phase and gain of 3°and 3% . (3.) Allowance must bemade for dot interlace of the 3.58-MHz chroma subcarrier informa-tion.

There are several ways to producedelayed substitution material fordropout compensation, and a num-ber of circuit variations have beentested. All involve detection of thesignal defect in the radio -frequencyportion of a magnetic video record-er; they differ as to the location inthe playback circuit where informa-tion is stored and re-inserted, and asto the sequence and duration of theseinsertion periods.

FM Compensation

One possible method employs anFM dropout compensator in whichdetection and substitution are ac-complished in the RF signal portionof the reproduce electronics. In sucha system, the FM signal is delayedand used directly for substitution.This is the simplest method forwideband monochrome information,since the FM carrier can be trans-mitted directly through a high -fre-quency glass or quartz ultrasonicdelay line. However, FM substitu-tion in the RF signal produces thesame sort of discontinuity as an FMhead -switch transient at the begin-ning and end of the dropout pulse,due to the introduction of a consid-erable phase discontinuity. Thismethod cannot properly compensatethe first and last portion of the drop-out.

There are other problems: Ring-ing and spurious signals in glassdelay lines distort the stored infor-mation. Also, the dispersive charac-ter of these delay lines tends to shiftthe FM axis and cause a level errorin substitution. These problems aredifficult to overcome.

Video Compensation

In a second basic system, theprincipal delay and switching opera-tions are accomplished in the video -signal portion of the recorder/play-back system, after demodulation ofthe RF carrier. This usually is calleda video -substitution compensator(8). It has the advantage that theinherent delay of the filter and de-modulator can be used to insure thatthe dropout substitution starts beforethe actual disturbance. Video switch-

ing can also be done with notransients, and the fill-in match inluminance and chrominance can bemade nearly perfect.

A video delay system for NTSCcolor presents special problems be-cause of the nature of the signals.The color subcarrier (3.579545MHz) is 227.5 times the horizontalline rate. Thus, the subcarrier is au-tomatically phase -inverted 180° oneach successive scan line. A delaysystem timed exactly for one hori-zontal line stores the signal for oneline but will not phase -invert thesubcarrier. If this type of delay sig-nal is switched into the direct videosignal as a substitution, the nonin-verted chroma signal will producethe wrong color.

There are several possible solu-tions to this problem, such as: (1.)Store the delay signal for two linesinstead of one. (2.) Set the delaytiming either long or short of exactlyone line by one-half cycle of colorsubcarrier. The first approach is un-satisfactory because time -base errorsin the recorder or fill-in materialerrors become twice as objectionableas in the one -line system. It alsorequires twice the delay bandwidthproduct. The second method cannotbe used with direct color -recoverysystems, since the time -correctingelements will restore this introduceddelay timing error whenever there isa droptout in sync. This will causethe entire line to flash a wrong color.A lockout during sync has similarproblems, since the absence of syncpulses or burst also puts a false errorsignal in the direct color -recoveryequipment.

A third method is to separate thecolor signals from the monochromevideo signal, invert the color signal180°, and recombine it with themonochrome signal. This system re-quires additional circuitry and canbe used only with a video compen-sator. It introduces phase discon-tinuities in the monochrome signalabove 2.5 MHz. Despite these diffi-culties, this method produces thebest overall results.

Another problem associated withprocessing an NTSC color signal isthe effect of differential phase andgain on the color information. Thethird method of color correction,described in the preceding para-graph, is insensitive to this effect, asthe color signal can be delayed andprocessed independently of the


0

I.

CIRCULARIZED!JAMPRO CP-IX FM ANTENNAS

The only true circuk,rly polarizedFM antenna with variable power ratio

VARIABLE HORIZONTAL TO VERTICAL RATIOS areavailable only in .11AMPR3 circularized antennasThese ratios ma/ be acjusted frcm 5J-50 o -varied to other oercentages up to 9O% liorizcitaand 10% veriiiEXCLUSIVE DBITAL TUVIN.3 END STLBS allow 3x.-treni(ly low vMR. IAMPF:0 gLarantees a V.SINF!of under 1.1 tc 1 w len mounted cr your ..oAT,r.then held tin me( "D 1.08 :o 1, carrier, t 2001;C.

A MA Division of Computer Eziu pment Corr

AVAILABLE IN TWO DIFFERENT FEED SYSTEMSPARALLEL SYSTEM using ndividjal interbay cablesfrom one power divide-, -exulting in the best

possible FM antenna perle-manceSHUNT SYSTEM wth e ?ments across a single

31/2" rigid coakl line.TAKE A CIRCULAR STEP!Write for full specification;, cr make a circularmotion on your phoie dial (913) 333-1177.

R 0ANTENNA COMPANY

8933 PAER INN ROAD SACRAMENTO, CALIFORNIA 95828


February, 196823

luminance level. A 2.5 -MHz band-width is required of the luminance(monochrome) signal to provideproper sync rise time. Otherwise,dropouts in sync, compensated ornot, would destroy the color -signalphase relation in direct color -recov-ery systems.

Color VideoCompensator Design

A block diagram of a completecompensator is shown in Fig. 1. Thedetector actually is a double-actingdevice. First, a constant -currentsource applies the RF signal to thelevel -detector stage, tunnel diodeD 1. The RF drive causes D1 tochange state on the peaks of the RFpulses, resulting in a square wave.The threshold -level control adjuststhe gain of the amplifier stages todetermine the lowest RF level whichwill cause DI to fire. The squarewave from the dropout detector isused to reset repeatedly a ramp gen-erator. If the generator is not reset(as is the case if loss of RF inter-rupts the square -wave output fromD1), the ramp continues to rise andeventually triggers the dropout pulsegenerator. This double process cor-relates the depth and duration of theRF amplitude disturbance for faster

and more accurate dropout detec-tion.

The delay caused by the rampgenerator is just long enough to per-mit the activation of dropout substi-tution before the beginning of thedropout, which occurs in the video ata time delayed from the FM by thedemodulator and filter in the re-corder.

A detector timing adjustment con-trols the time lapse between loss ofRF and dropout pulse generation.This adjustment is set to delaytriggering just long enough so thatthe detector ignores spikes in the RFcaused by such defects as noise andpre -emphasis in the video -recordersystem for black -to -white transition.

The pulse circuitry extends thedropout signal for a short durationin case any limiter disturbance fol-lows the dropout interval. The nega-tive -going dropout pulse is routed tothe video switch. The video switchis placed in the output of the re-corder demodulator after filteringbut before any sync separation orsignal division. If this cannot bedone, separate dropout protectionmust be devised for tape signal pathsnot routed through the switch.

The heart of the storage system isa pair of special glass memories. The

Please turn to page 42.

1.

References

Video Talk, Bulletin No. 2. St.Paul, Minn.: Minnesota Miningand Mfg. Co., March 1, 1960.

2. Carson, R. H. Dropouts in Mag-netic Tape Recording Systems,Washington, D. C.: U.S. Naval Re-search Labs. From an IRE paperoriginally presented at the 1962IRE Convention, New York.

3. Wallace, R. L., Jr. "The Reproduc-tion of Magnetically Recorded Sig-nals," 1924 BSTJ, 30, Pt. 2,(October, 1951), 1145-1173.

4. Benussi, V. "Zur Psychologie derGestalterfassens," A. Meinong,"Untersuchung Gegenstandstheo-rie," 1904, 303-448.

5. Rubin, E. "Visuell wahregenom-mene Figuren," COPEN, Gylden-dalska, 1921.

6. Wertheneisner, M. "Untersuchun-gen zur Gestalttheories." Erlangen,Philosphisehen Akademie, 1923.

7. Heider, G. M. "New Studies inTransparency, Form, and Color,"Ps Forsch 17, 1932, 13-55.

8. Moskowitz, I. "Compensator," U.S.Patent No. 3,328,521, June 27,1967.

9. Fink, D. G. Television EngineeringHandbook. New York: McGraw-Hill Book Co., 1957.

I II I III1 W

11 1 1 IFROM RF

FM BRIDGINGAMPLIFIER

SW ITCHERIN VTR

VIDEO FROM

DEMODULATOR

SWITCHPULSE

1 1 I 1 1 1 1

THRESHOLD

LEVEL I II III

GAIN GAIN

DITUNNEL

DIODE

DETECTOR

DELAYED

VIDEO

VIDEOSWITCH

LUMINANCEDELAY

CHROMADELAY

POST AMP

VIDEO TO VIDEOOUTPUT PROCESSINGEQUIPMENT

Fig. 1. Dropout compensator routes luminance, chrominance through separate delay lines, also uses demodulator delay.24

BROADCAST ENGINEERING

Instant Audio:You create your own customized professional equipment with our

Finished Solid -State Circuit Modules.

Make intercoms, line amplifiers, mixers, monitors, turntable pre-amphfiers, stereo amps,language labs, etc. They'll be better, cost you less.

Just create your own electronics with our Finished Solid -State Circuit Modules. Make audio/RF/communications/radio-controlled systems. Quality will be high, cost you less.

AA -100

UTILITY AMPLIFIER

For general purpose uses; and tomodulate TR-100 Transmitter (be.ow). Includes volume control andnput (low Z) and output trans-

formers.

AUDIO AMPLIFIERS

AA -300

PROFESSIONALAMPLIFIER

Designed for broadcast/recording/TV uses. Includes input and outputtransformers.

AA -400PROFESSIONALPOWER AMPLIFIER

When driven by AA -100 or AA -300,a hi -gain 1 -watt audio systemresults.

AA -500

PROFESSIONALPRE -AMPLIFIER

Specially designed for broadcast/TV/recording/hi-fi/commercial usage. With any low-level hi -Z input de-vice, they deliver undistorted 5VRMS to drive a hi -Zinput power amp. Usable with low-level low -Z mikesif fed by quality input transformer (150 to 50K 12balanced). To feed 600 0 lines, use a transformer(2.5 to 6(40 12 balanced) in the output stage.

Model AA -100UTILITY

AMPLIFIER

Model AA -300PROFESSIONAL

AMPLIFIER

Model AA -400PROFESSIONAL

POWER AMPLIFIER

Model AA -500PROFESSIONALPRE -AMPLIFIER

Model AA -500RPROFESSIONALPRE -AMPLIFIER

Model AA -500NPROFESSIONALPRE -AMPLIFIER

Freq. Resp. ±3db, 100-12K cps +1db, 20-206 cps, 200MW±2db, 20-35K cps, 100MW

-±ldb, 20-206 cps, 1W -±1/2db, 20-20K cps RIAA-Equalized NAB -Equalized

Harmonic Dist.. <3%, 100-12K cps <1%, 20.20K cps, 100MW<2%, 20.20K cps, 200MW

<1/2%, 20-20K cps, 1W <0.5% 20-20K cps <0.5% 20-20K cps <0.5% 20-20K cps

Input Z 50.150 Si (shieldedtransformed 8 1006 n

50-150 St, or 600 El, balanced(mu -metal shielded permalloycore transformer)2K or 1006 0 unbalanced

500 El & 26 0 48K 0 IMay be used withinput transformers)

4860; (May be used withinput transformers)

48K it (May be used withinput transformers)

Output Z 500 11 & 8 0 (grain orientedtransformer) 200MW

500 0 & 8 0 (grain orientedtransformer) 200MW

4-16 fl (OTL) 56 2": (May be used withoutput transformers)

5K fi- (May be used withoutput transformers)

56 ti (May be used withoutput transformers)

Gain 70db 80db 124 for 1W output 70db 70db 70db

Circuit 5 transistors, 1 thermistor 7 transistors, 1 thermistor 5 transistors 4 transistors 4 transistors 4 transistors

Power 9VDC, 50MA 9VDC, 100MA 14VDC, 200MA 40VDC, 5MA 40VDC, 5MA 40VDC, 5MA

Size 51/2" Lx13/4"Wx 1"H 8"Lx 21/4"Wx 11/2"H 5" L x 21/2" W x 2" H 41/2" L x 3" W x 11/4" H 41/2" L x 3" W x 11/2 " H 41/2" L x 3" W x 1Vx" H

Weight 31/2 oz. 12 oz. 4 oz. 2 oz. 2 oz. 2 oz.

Price $7.95 $14.95 $10.95 $23.95 $23.B5 $23.95

REGULATED POWER SUPPLYZener-referenced, delivers highly stable, extremelylow ripple DC output of 9VDC with loads up to200MA; andunregulated 14VDC at 1 Amp. For wher-ever well -filtered regulated DC is needed. Input:105-120VAC, 60cps, 5W. Regulation: Line + load5MV. Ripple: Under full load 10MV, p -to -p. Max.Load Current: 200MA. 41/2" L x 2" W x 11/2" H.Wt.: 23 oz. (with transformer)

PS -300$18.95

TRANSMITTERComplete crystal controlled 3 -transistor transmitterfor Citizens' Band. Factory pre -tuned for any CBchannel; supplied with channel 10 crystal. Modula-tion: CW or AM with external modulator such asAA -100. RF output: 100MW, 50 load. Power: 9VDC,50MA. 51/2" L x 13/4" W x 2" H, 31/2 oz. Add. CBCrystals: $3.00 ea.

$10.95

Please send me the following circuit boards:

Model Qty. Price ea. AMOUNT

AA -100 Utility Amplifier $ 7.95 $

AA -300 Professional Amplifier 14.95

AA -400 Professional Power Amplifier 10.95

AA -500 Professional Pre -Amp 23.95

AA -500N Professional Pre -Amp 23.95

AA -500R Professional Pre -Amp 23.95

PS -300 Power Supply 18.95

TR-100 Transmitter 10.95

OS -100 Power Oscillator 21.95

TOTAL

POWER OSCILLATORAll -transistor push-pull sine wave oscillator, 20KC150KC, 1% harmonic distortion. Power needed: 18-22V, 100MA. Input terminals permit AM modulation(by amplifers AA -100, 200, 300). Uses: biasing recorder heads, powering tape erasers, signal gen-erator/transmitter. 5" L x 3" W x 2" H.

"P' ROUND HILL ASSOCIATES, INC.ta434 Avenue of the Americas, New York, N. Y. 10011

Li Send postpaid: enclosed is full payment. El Send C.O.D. B E-2

NAME

ADDRESS

CITY

STATE ZIP

DEALERS INVITED.

February, 1968 25

A PUSH-BUTTON

MASTER CONTROL

This master control unit was de-signed to meet a twofold objective.It was to tie in with an announcestudio that was of itself as nearbreakdown -proof as possible', andit was to fit into an operation thatcould be adapted eventually for anontechnical staff.

In a normally busy 50 -kw metro-politan station, the line patchingpanel is a confusing array of patchcords connecting the various partsof the station system. To aggra-vate this condition, reel-to-reel tapemachines and monitor systems haveto be connected or disconnectedmany times during the busiest timesof the day. When an operator goesoff shift, it takes even an experiencedreplacement some time to trace outthe various interconnections thatconfront him, and sometimes thisleads to serious error.

At first thought, it seems a verycomplicated project to "push-but-ton" 100 remote lines and their' Len Spencer, "A Doubly Reliable Console,"

Jan. 1968 BROADCAST ENGINEERING, p. 12.

IMO

4 idatadminidamindiiiIsi

by Len Spencer-- Push-button control takes the panicout of the "panic period" at this busy station.

ancillary equipment. And, the eco-nomic factor had to be considered,also. After a study in depth wasmade, however, it became apparentthat many of these interconnectionswere in use almost continually sothat it was possible to establishpriorities of importance.

At CKAC, program commitmentsare made in 13-, 26-, and 52 -weeksegments. It was decided, therefore,that the respective incoming jacksfor the longer -term programs wouldbe paralleled with numbers 1, 2, 3,etc., on the push-button matrix. Inno case did we destroy the availabil-ity of the jack bays or deprive our-selves of complete flexibility ofpatch cords if and when required.

It was also thought prudent toassign different colors to the illumi-nated buttons of each master -con-trol bay so that all interconnectionscould be seen at a glance. To thisend, the control desk is divided intothree sections, remote programs(with their telephone circuits)

1111111

111111119r=1111111101111111111111111111111111111

switching panel, and level -controlpanel. In this article, these sectionswill be referred to as Bay No. 1, BayNo. 2, and Bay No. 3, respectively(Fig. 1). Fig. 2 shows the basiccircuits as they relate to the variousbays.

Remote -Line Switcher (Bay 1)

At the top of each bay are thevolume indicators associated withthe function of the bay. In Bay No.1 (remote -line switcher), volumeindicator No. 1 indicates the outputof a line amplifier which is fed froma line transformer common to thetop row of remote selector buttons;the level is controlled by the po-tentiometer at the right of this row.The second volume indicator is as-sociated with the second row ofbuttons and has its own line trans-former and amplifier. Both outputsare normal to the bay but can bepatched out at a jack strip if re-quired.*BROADCAST ENGINEERING Consulting Author,

Montreal, Quebec.

IIIIIIIu

aaa%BAY 1 BAY 2 BAY 3

Fig. 1. The push-button master control. The functions of the numbered bays and VU meters are described in the text.


PR

OD

LIN

ES PE

48 1 27

NO

TE

S.

1. A

C-

- S

WIT

CH

CR

OS

SP

OIN

T

2.-

RE

LAY

CR

OS

SP

OIN

T

3.F

OR

LIA

R II

Y, O

NLY

SIG

NA

L P

AT

HS

AR

E S

HO

WN

. PA

TC

HIN

G, P

AY

S,

AN

D O

TH

ER

DE

TA

ILS

AR

E O

MIT

TE

D.

V U

1

TO

MO

O 5

0

(

RE

MO

TE

1

RE

MO

TE

2xe

ST

UD

IO A

ST

UD

IO 8

X I

ST

UD

IO C

XN

EW

S 5

1001

0X

'

TA

PE

I

TA

PE

2x

-T

AP

E 3

C(

(

TA

PE

4

SP

AR

EI-

5-'

oTO

V1.

14M

ON

6

TO

MO

N 7

FIH

1

TT

(0

X X

X X

X X

TA

PE

I

TA

PE

2

C

TA

PE

3

TA

PE

4

MIC IN

5h

O

0 o

17

34

MO

NIT

OR

89

101'

ISP

AD

EI

OE

-A

IRR

EC

EIV

ER

VU

5

LiF

u

I I 2'

AU

L.

_iyo

VU

6

0M

ON

!I

TO

MO

N 9

AG

CT

O

PA

TC

H

PA

NE

L

riTLI

MLI

NE

S T

O

TR

AN

SM

ITT

ER

TO

ST

UD

IOS

10A

ND

CE

NT

RA

LM

ON

10

RE

CO

RD

ING

BA

Y1

BA

Y2

BA

Y 3

Fig

. 2. B

asic

aud

io r

outin

g in

the

mas

ter

cont

rol s

yste

mis

det

erm

ined

by

push

-but

ton

switc

hes.

All

norm

al p

atch

ing

capa

bilit

ies

are

reta

ined

in a

dditi

on to

this

uni

t.

The incoming lines are in parallelwith 10 monitor -selector buttons inthe fifth row down. This allowsmonitoring and level adjustment ofany of the 10 remote lines before itis punched up on the program bay(Bay No. 2).

The bottom row contains the tele-phone signalling and calling controlbuttons, which are illuminated byany incoming calls from a remoteprogram point.

The monitor speaker is connectedto the remote matrix by means ofthe six monitor -speaker buttonsalong the left-hand side of the bay.

Master Switcher (Bay 2)

On the center panel are foundoutputs from four studios and fourreel-to-reel tape machines, and theindividual start -stop and rewind con-trols for the tape decks. It is pos-sible to record on one or two ofthese tape machines and play backon the air one or both of the others,or to record on the four machinessimultaneously, from any of the re-mote lines or studios. Every studiooutput also appears in the record-ing department, as do four remote

By means of the No. 3 volume in-dicator, any feed associated with thetwo rows of buttons at the lowerleft may be checked. The top rowcarries four studios plus remotelines, and the bottom row includesthe feeds from any prepunched re-mote, two transmitter inputs, andthe radio receiver. The controllingpotentiometer is situated directlyabove these rows of buttons.

The second control strip from thetop is the preselector; this allows theoperator to set up as many as tensupplies, from tapes, remotes, fourstudios, and any prepatched pro-gram. When they are to be put onthe air, the single push button at thecenter is operated, and a correspond-ing indicator in the top row of illu-minated status lights goes on. Thelevels of these programs are con-trolled from Bay No. 3.

At the bottom center of Bay No.2 are four rows of six buttons, whichare the switchers for the four taperecorders. These allow recordingfrom any remote point or studio.The start, stop, and rewind buttonsare to the right of each row.

Instant intercom is, of course,very necessary, and this function issupplied by the final two rows ofbuttons at the right of this bay. Theloudspeaker for all operations isadjacent to meter No. 5

Level -Control Panel (Bay 3)

The choice of program destina-tion, either to the transmitter or tosome other point, is made by thepush buttons at the tops of the sixslider potentiometers.

The No. 7 volume indicator isacross the line after the level -controlamplifier. The No. 5 indicator (onthe switching panel, Bay 2) is con-nected across the detector circuit ofa radio receiver; it is adjusted sothat the fluctuations of both level in-dicators (5 and 7) coincide. Thisdouble check shows if there is asudden drop of level on the trans-mitter feed line, a reduction in radiooutput power, or low modulationcaused by tube failure anywherebetween studio and antenna.

Volume indicator No. 4 is usedto pre -adjust the levels from the dif-ferent sources. When all is in order,operating the single button betweenthe two upper rows of Bay 2 trans-fers the preselected program to theair via the indicated potentiometeron the level -control bay. To accom-plish this, a high-speed magneticlatching crossbar switch is used. Thisdevice has a switching time of 2-5milliseconds and draws about 200milliwatts momentarily during oper-ation; no holding current is required.It is basically a multicontact relaywith twelve coupling systems and arestoring assembly that is commonto all twelve systems. In the switch-ing panel, this multicontact relay isused for switching on the statuslights and feeding twelve functionsto program -output and mixer -inputswitches.

Below the potentiometers are but-tons that permit overriding the pre-select so that, if necessary, all sixprogram sources can be mixedand/or faded into the output cir-circuits. Since. these switches aredouble throw, 12 feeds are thusavailable.

The final row of buttons at theextreme right of Bay 3 containsemergency -operation controls. TheN button for normal operation is

colored green, and the u for urgen-cy is, of course, red. Should anycomplication arise, it is possible tobypass the three bays and put anyof the four studios on the air directlyby connecting it to the transmitterprogram line. The switches also con-nect the transmitter order wire orphone line directly to whateverstudio is selected. They can also beparalleled if required.

Using the System

On reading the detailed operationof this complex, one would be rightin questioning the basic policy thatled to its construction, since it ap-pears that a great deal of effort andingenuity has gone into replacinga dozen or so patch cords. This,however, is not the case.

A stopwatch has been used totime elementary set-up. With theold method there was much wastedeffort and time loss, and if the easeof determining the exact operationafter each operator shift change isconsidered, the project was and isworthwhile.

Consider a typical operation,which consists of patching a remoteprogram and a prerecorded programfrom a tape recorder into the mastermixer using patchcords and a jackfield. In most cases, the mixer sec-tion in the control room is operatedfrom a sitting position. Therefore,the operator would have to leavehis control board, go to the jackbay and answer the remote phone,select a patchcord, find the correctjack, manipulate a volume controland patch another circuit into hismixer, and then look for anotherpatchcord, patch the output of thetape recorder to his mixer, and startthe tape machine before returningto his control position.

All this can be accomplished onthe push-button control in 7.5 sec-onds without moving from the mixercontrol position! And, as each buttonlights, the exact status of the cir-cuitry is clearly indicated. It is dur-ing "panic periods" that this modernapproach is appreciated most.

The overall concept of the sys-tem described in this article was de-veloped by the author. Constructionand assembly were in the hands ofN. J. Pappas & Associates, whoseassistance is gratefully acknowl-edged.


simultaneous record & playback

...plus dubbingwith Collins' new compact Twintape SystemCollins' new Twintape System, completely solid-state and avail-able in monaural or stereo models, is the most convenient, flexible,and easy to operate cartridge machine on the market. The TwintapeSystem consists of two units: the 642E Twintape Playback Unit,and the companion 2 I 6D Record Amplifier. Combined, theseunits permit:

Playback on both cartridges simultaneously. Recording on one cartridge while playing the other. Dubbing from one cartridge to the other.

I ape transport assemblies in the Playback Unit are easily re-moved. Rugged, direct -drive capstan motors eliminate flywheels,rubber belts, etc., and produce extremely low wow and flutter.With extra heavy Mu -metal magnetic shields, the unit has verylow susceptibility to magnetic pickup of noise. Rear terminalstrips provide for optional remote control, automatic sequencing ofmultiple machines, cue detector contact outputs, etc. Routine main-tenance of the Playback Unit may be performed in seconds.

Cue tone oscillators, record level metering, operationcontrols, and an amplifier are contained in the216D Record Amplifier. One cue tone isstandard, with option for three cuetones. The amplifier may he stackedcompactly with the Playback Unit, orrack mounted with an optional adaptor.

All Twintape System electronic circuitsare mounted on plug-in, etched epoxy boards.

For a descriptive brochure on this new Twintape System, writeor call Broadcast Communication Division, Collins RadioCompany, Dallas, Texas 75207. Phone (214) AD 5-951 I .

COMMUNICATION / COMPUTATION /CONTROL

CO LLI N S


MAINTENANCE OF THE

DIRECTIONAL ANTENNA

As the final "output" of the entirestation, the antenna system is oneof the most important items in theplant; yet, it is probably the mostfrequently neglected with respect tomaintenance. It is of particular im-portance that a directional antennabe maintained properly, since itmust confine the radiated signal tocertain areas specified by the stationlicense or construction permit. Itmust present the proper load imped-ance to the transmitter, and it mustbe stable. If the antenna system failsto perform these functions properly,interference may be caused to otherstations; null points may shiftazimuth position, causing listenersto complain of weak reception; orthe common -point impedance couldchange, preventing proper transmit-ter loading.

by Barry Atwood*-Care and common sense are the chiefingredients in keeping this portion of the station in good order.

It is helpful if the antenna systemis considered in terms of severalsubsystems (Fig. 1); each of thesesubsystems will be discussed in termsof its functions and maintenance re-quirements. It is realized that nodetailed maintenance program canbe devised which will apply univer-sally to all directional antennas.Each system is designed for a partic-ular application, and each has itsown peculiarities. However, a num-ber of basic principles may be ap-plied to any directional antenna, solong as the engineer has an under-standing of the operation, tolerances,and specifications

Phasing System

In many respects, the phasor isthe "heart" of the antenna system.

TRANSMITTERINPUT

GROUND_SYSTEM

PHASOR

TRANSMISS IONLINES ANTENNA

TUNING PHYSICALUNITS ANTENNA

rCOMMON

INPUTPOWER

DIVIDERPHASING

AND(COMMON BRANCHING MATCHING

POINT) CIRCUITS

11MATCH ING

CIRCUITS

._

MONITORING SYSTEM

It is here that the power output fromthe transmitter is divided in theproper proportions and with theproper phase relationships to feedthe line to each tower. The phasoralso must present the proper loadimpedance to the transmitter. Toaccomplish these ends, a combina-tion of inductors and capacitors,fixed and variable, is employed inthe phasor.

The inductors and their connec-tions place resistance as well asreactance in the cirucit. This resis-tance must be kept as low as pos-sible, to minimize power dissipation.Since dirty or corroded connectionspresent a high resistance, one of themost basic rules of any maintenanceprogram must be observed: Keepconnections as well as componentsclean. For the same reason, all con-nections must be kept tight. In thecase of variable inductors, theserules apply to the movable contactsas well. Do not forget the drivemechanisms for variable coils; thesemust work freely without binding.The drive system should be checkedfor sufficient lubrication, and if thereare any loose parts, appropriate re-pairs should be made. All insulatorsmust be kept clean, to prevent leak-age and possible arcing.

Capacitors require much the samemaintenance as inductors. Theymust be kept clean, and connectionsmust be tight. Mica capacitorsshould be checked for cracks in theceramic center portion, and vacu-um capacitors should have the glassinspected, especially at the endseals. Drive mechanisms for variablecapacitors should be checked in thesame way as those for variable coils.Gas -filled capacitors should bechecked to insure proper pressure.

Fig. 1. A directional antenna may be considered to be made up of subsystems.

30

*Chief Engineer, WT3KY, Lexington. Ky.


Do not overlook connections tothe station ground, meter -shortingswitches, RF contactors, or any oth-er component in the RF path. Allthese should be kept clean and tight.RF relays should be checked forpitted contacts, improper contactalignment, and overheating of thecoil.

Since the entire power output ofthe transmitter is applied to thephasor, heat will develop anywherethere is a defective component orpoor connection. All of the phasorcomponents should be checked forsigns of overheating after sign -off.One important point should be con-sidered, however: If the stationoperates with reduced power atnight, the system should be operatedat full power for about one-halfhour during the experimental periodbefore this check is made. A com-ponent which is approaching failuremay feel quite cool after a run onlow power, but become hot on ratedpower. (Of course, componentsshould not be subjected to powerlevels in excess of their ratings, ordamage may result.)

A few other points deserve con-sideration: Most phasor cabinetsare interlocked, and these interlocksshould receive the same attentiongiven those on the transmitter; besure they are operating properly!Lightning can do severe damage toantenna equipment; if an electricalstorm is experienced, the entirephasor should be inspected aftersign -off for indications of damageand component overheating. A finalpoint to be considered in phasormaintenance is common -point im-pedance; if this impedance is incor-rect, the radiated power may alsobe incorrect.

Fig. 2 shows a portion of the in-side of a typical phasor. Notice thegas -filled capacitor at the left. Themetal box at the bottom right ofthe photograph is an in -line typeof common -point impedance bridge;this type of bridge permits measur-ing the common -point impedancewhile the station is on the air. Thelarge coil in the center, in conjunc-tion with the gas -filled capacitor,constitutes the input tank circuit.It is here that the power tap -offsare made; this is an important spotto check for overheating.

Fig. 2. Gas -filled capacitor (left), coil with taps, in -circuit bridge (lower right).

Transmission -Line System

Transmission lines may be buriedor above ground. They may have asolid dielectric, or they may be filledwith an inert gas or dry air. Mainte-nance of buried lines is limited tothe accessible end terminations orseals, to the maintenance of propergas pressure, and to checking forobvious faults, such as lines whichhave worked out of the ground,plow cuts, etc. Regardless of thetype of line, all end seals must bekept scrupulously clean. Pressurizedlines should be checked for leaks;gas or air pressure should be main-tained at the level recommended bythe manufacturer. Each end of thetransmission line is bonded to theground system, and these bondsshould be checked for security andcorrosion.

Rigid copper lines installed abovethe ground require special consid-eration. Expansion and contractionwith temperature variations may

Fig. 3. Rigid coax line buckled whensubjected to variation of temperature.

cause the lines to buckle, or to sep-arate at the joints. Fig. 3 showstransmission lines which have buck-led from this cause. A right-anglejoint can be a particular troublespot because the stresses are ap-plied from different directions. Theupper line in Fig. 4 separated at adouble right-angle joint such as inthe line just below. The rigid anglejoints were removed, and a sectionof flexible line was spliced in place.

Matching System

The antenna tuning unit mustmatch the impedance of the towerto the impedance of the transmis-sion line. Depending on the designof the system, part of the current

Fig. 4. Right-angle joint separated,was replaced with a curved section.

February, 1968

Maybe our microwave STL system can put you inclover. Its color performance exceeds FCC, EIA, andCDR. Its reliability can't be beat, and maintenance isnegligible. The reason ... our all -solid-state design. Notubes, no mechanical relays, no klystron.Whether you're upgrading an existing STL capability,moving to new quarters, or changing transmitter sites,it'll pay to check out our STL systems ... single or dual.Units are typewriter size and available for 2, 7 or 13GHz bands, with optional manual or automatic switch-over. Single or multiple audio multiplex too.Joil 200 other green thumbs. Ask for Catalog SF -9501.

Is the grassalways greener

on the otherchannel?

MICROWAVE ASSOCIATESBurlington, Massachusetts

Offices: Northwest Industrial Park, Burlington, Wa. a1803;3605 Long Beach Blvd., Long Beach, Cal, 50807International Sales: Microwave Associates Internet .)nilNorthwest Industrial Park, Burlington, Mass. 010.1'

Ci cle Irerr 3; J i Tech Date Card

phasing may be accomplished here also. The matchingsystem may include remote sampling units for measur-ing antenna base -current magnitude and phase; thesewill be discussed in a later section. In the series -excitedarray (the most common type), some means must beprovided for isolation of the tower -light wiring, and ofthe phase -sampling line if a tower -mounted samplingloop is employed.

The antenna matching unit contains many of thesame kinds of components as the phasor. Therefore.everything that has been said concerning phasor main-tenance applies to the antenna tuning units (with theexception of impedance checks). The frame on whichthe matching -system components are mounted, if it

is metal, is also bonded to the ground system, alongwith the end of the transmission line and phase -sam-pling line. This is an especially important place tocheck for loose or corroded connections.

Mice, rats, snakes, and other vermin have a habitof seeking refuge from the elements inside the match-ing -system enclosure. This must be discouraged asmuch as possible. Mice have been known to nest insidecoils and thus upset the operating constants. Also, theymay be "fried" when they come in contact with con-ductors carrying RF current. The enclosure should bekept clean, and all openings should be sealed to pre-vent entry. Poison baits may also be employed.

Towers

At first glance, it may appear that there is little to bemaintained about a tower. Nothing, however, could befurther from the truth. The tower must be plumb andwithout any evidence of torque damage. The tower paintmust be in good condition, as required by the FCC andFAA rules. The guy wires must have the proper ten-sion, and fasteners and anchors must be secure. Thebase insulator must be kept clean, and there must beno sign of cracks or other damage. The lightning gapmust be spaced properly, and the ends must be cleanand free from obstruction.

The tower lighting system must be maintained in goodorder. This includes the obstruction lamps and anyalarm or indicator devices, photocell systems, and rota-ting or flashing beacons. FCC rules require that an in-spection be made every three months of alarm or indi-cating devices and automatic or mechanical controlsystems. At some stations, a tower rigger is employedto replace all the tower -light bulbs at three-monthintervals. The other checks should be made at thistime also. But regardless of who does this work, be surethat everything is checked. In systems which employ aphotoelectric control, the cell must turn on the lightsat the proper light level (northern skylight intensity of3 foot candles). If the lighting -control uses tubes, theyshould be tested at monthly intervals. Relays shouldreceive standard maintenance. The opening in front ofthe enclosure which permits the light to strike thephotocell must be clean and free from obstructions

Do not forget the actual RF connections to thetower. This is a likely place for temperature changes tocause a separation of the bond.

It is a good idea to observe the tower base insulatorsat least once during a rain storm. Poor -quality paint,or dirt on the tower, may be washed across the base in -

"Want a Good Jobin Broadcasting?

You'll Need aFirst Class FCC License."Matt Stuczynski knows. He's the Senior Transmitter Operator ofRadio Station WBOE. His story is typical of hundreds of men whohave used Cleveland Institute Training as a springboard to successin Broadcasting. Here's what Matt says about Cleveland Institute:

"I give Cleveland Institute credit for my First Class FCC License.Even though I had only 6 weeks of high school algebra, CIE'sAUTO-PROGRAMMEDTm lessons really made electronicstheory and fundamentals easy. After completing the CIE course,I took and passed the First Class Exam. I now have a good jobin studio operation, transmitting, proof of performance, equip-ment servicing. Believe me, a Commercial FCC License is a'must' for a career in Broadcasting."

If you want rapid advancement in broadcasting, the first step is aFirst Class FCC ticket with your name on it. And Cleveland Insti-tute Home Study is a fast, economical way to get one. What's more,CIE backs their licensing programs with this money -back warranty:

"A CIE License Course will quickly prepare you for a FirstClass FCC License. If you complete the course but fail to passthe exam on your first attempt, CIE will refund all tuition."

With Cleveland Institute you get your First Class FCC License oryour money back! Send coupon today for FREE book or write toCleveland Institute of Electronics, 1776 E. 17th St., Dept. BE -44,Cleveland, Ohio 44114.

ENROLL UNDER NEW G.I. BILLAll CIE courses are available under the new G.I. Bill.If you served on active duty since January 31, 1955, orare in service now, check box in coupon for G.I. Billinformation.

L

N

MAIL COUPON TODAY FOR FREE BOOK

CIECleveland Institute Iof Electronics II

1776 East 17th Street, Cleveland, Ohio 44114 1

II

II

Please send me your FREE book, "HowTo Get A Commercial FCC License."

Name(please print)

Address

City lip II

Occupation Age 1

ID Veterans check here for GI Bill information I

Accredited Member National Home Study CouncilII

A Leader in Electronics Training ... Since 1934 BE -44 j

State

February, 1968


33

sulator. This mixture may ignitewith the RF energy present andburn a path across the insulator.The bottom of the antenna base in-sulator is bonded to the ground sys-tem, along with one side of thelightning gap. Be sure to check theseconnections. Fig. 5 illustrates atypical base insulator and the RFfeed line, lightning gap, and groundconnections.

Guy -wire anchors which employexposed turnbuckles are subject to"cattle itch." In areas where cat-tle roam the antenna site, they may

scratch themselves by rubbing alongthe turnbuckle or the guy wire.This can cause the turnbuckle tounwind. Fig. 6 .shows a more pro-tected installation in which the turn-buckles are enclosed. Be sure tocheck all guy bolts and wire clamps,and do not overlook the foundation.

Ground SystemThe FCC Rules establish mini-

mum effective field intensities forthe various classes of AM broad-cast stations. To meet these require-ments, a rather extensive ground

NOWTELE - IFIWAT

is the ONLY TEST PATTERN ILLUMINATOR for

100% TV COLOR or MONO -CHROME CAMERASET-UP/PERFORMANCE CONTROL

PROTECTEDTEST SLIDESTORAGE

REMOVABLE PANELTO FACILITATEDIFFUSER ADJUSTMENT.

SHADOW BOXDESIGN PROTECTSTEST PATTERN FROMAMBIENT LIGHT

MAGNETICSLIDE FRAMELOCK

KEYED SLOTSTO ASSUREPOSITIONING

RIGID ALL METALSPECIALLY CONSTRUCTEDSUPPORT AND BASE

4" DIA. RUBBERWHEELS - 360° ROLLER BEARINGROTATION - WITHLOCKING DEVICE

SPECIALFLOOR LEVELINGDEVICE

REGULATEDPOWER SUPPLY

ETW

NYLON SLIDE ROLLERSAND LOCKING GATES

MICRO MECHANICALLIGHT SOURCEPOSITIONER(IN REAR)

MICRO MECHANICALLIGHT INTENSITYADJUSTER

HANDLES BOTHFRONT AND SIDESFOR PARALLAXADJUSTMENT

GEARED ELEVATIONADJUSTMENT

ON/OFFCONTROLSWITCH

Power Supply 115VFully Regulated .2"

Color Temperature 3100-K(Adj. 2900.-3300.K)

250 Ft. Lamberts 4%(Adj. 0-400 Ft. Lamberts)

ICAIP IrsMOVE IDTELE-MEASUREMENTS, INC.145 MAIN AVENUE, CLIFTON, NEW JERSEY 07014PHONE: (201) 473-8822; (212) 581-9020Providing the only complete line of precision test slides and illuminators for color and mono -chrome cameras.Send for catalog listing 8" s 10" and 2" z 2" test pattern slides available.

Fig. 5. Base assembly of a series -fedtower should have regular inspections.

system is necessary so that goodradiation efficiency can be achieved.This ground system normally con-sists of about 120 buried radialwires, each about 1/4 wavelengthlong, spaced evenly around eachtower. In cases where electrically talltowers (approaching 1/2 wave-length) are employed, a groundscreen may be used to reduce thedielectric losses caused by the highbase voltages which are developed.

The ground system around thetowers is the ground reference forthe entire system. The individualradial wires are brought up to thetower base and bonded to a ringwhich encircles the tower. The ringsfor all towers are then bonded to-gether and to the source, which in-cludes the phasor and transmitter,with heavy copper strap. All otherRF and audio ground connectionsmust somehow be made to this sys-tem, either inside or outside thetransmitter building.

All ground connections must beinspected for looseness and corro-

Fig. 6. Protected guy turnbuckles cannot be turned by rubbing of animals.



sion. The areas immediately sur-rounding the towers should beinspected to insure that none of theradials have worked out of theground or become cut. Any pathover which there is evidence of re-peated travel by a vehicle or live-stock should receive a thoroughcheck for broken radials. The areaadjacent to the towers, usually en-closed by a fence, must be keptfree from vegetation. This growthwill increase the dielectric losses ofthe system and may cause the arrayto become unstable with varyingweather conditions. And, finally,the tower fence itself shoud not beoverlooked.

Monitoring System

The monitoring system enablesthe operator to observe the oper-ating constants of the directionalantenna. Remote indications may beprovided for antenna base current,phasing, and common -point current.Any component mounted in the en-closure of the antenna tuning unitshould be given the standard checks.Look for loose and corroded con-nections. Be sure that any pickupdevices are in proper adjustment.Test any tubes or crystal diodes,and check the calibration at theproper intervals.

Inside the transmitter building orremote -control p o i n t, the samechecks apply. All meters should bekept clean, and their connectionsshould be tight. Cables from localto remote points should be checkedfor loose or corroded connections,and for any sign of damage to thecable body. Switches and calibra-tion potentiometers in the phasemonitor and remote -metering unitsshould be cleaned periodically withthe proper cleaner. Vacuum tubesor crystal diodes should be tested.

Remote indicating units are sub-ject to lightning damage, and theyshould be checked after an electri-cal storm. Coaxial cables connectedto the phase monitor may be pro-tected with lightning arrestors. Ca-bles should be spliced properlywhen damaged sections are replaced,because moisture which enters aphase -sample line may upset thephase indication. Fig. 7 shows anexample of a poor splice throughwhich moisture is almost sure toenter.

Preventive Maintenance ScheduleDaily

1. Check calibration of remote

antenna and common -point

meters.2. Check pressure in transmission

lines.

3. Check tower lights at dusk, andagain at dawn.

4. In the event of lightning, checktransmission -line end seals,

phasor and "dog -house" com-ponents, and tower lightninggaps for signs of damage.

Weekly1. Check all meters for incorrect

mechanical zero and bent

pointers.2. Check pressure in gas -filled

capacitors.3. Check operation of all inter-

locks and grounding switches.4. After sign -off, check all phas-

or and "dog -house" compo-nents for signs of overheating.

5. Clean enclosures of phasor

and "dog houses."6. Inspect, and if necessary ser-

vice, relays and RF contactors.7. Make general detailed visual

inspection of phasor and "doghouses."

8. Creck common -point imped-ance.

9. Make complete inspection ofground system.

Monthly

1. Clean all monitoring unitswitches and calibration po-tentiometers.

2. Check all tubes and crystaldiodes in monitoring units andtower -light control units.

3. Inspect, and if necessary ser-vice, all tower -lighting control,indicating, and alarm relays.

4. Inspect all variable -coil wipers.5. Clean phasor and "dog -house"

components.

Quarterly

1. Clean and tighten all connec-tions in phasor and "dog-houses."

2. Make complete inspection oftowers, guy wires, base insula-tors, lighting systems, andautomatic control or alarm sys-tems.

3. Check all exterior cables andtransmission lines for signs ofdamage.

Fig. 8 illustrates checking for theobvious. A wooden support beamfor the phase -sampling lines hasrotted away at one end, and thecables are now supporting the brace.

One final point: Do not overlookthe monitor -point field -intensityreadings. Improper readings are asure indication something is wrong(although the pattern shift may notnecessarily be the result of poormaintenance).

Fig. 7. Poorly made splice lets moistureenter; coaxial cable then deteriorates.

Conclusion

Shown here is a preventive -main-tenance schedule which may be ap-plied with but perhaps minor changeto most directional -antenna systems.The proper maintenance of yourarray is just as important as themaintenance you perform on thetransmitter or limiter amplifier. Reg-ular preventive maintenance willpay dividends in the form of fewerviolations and fewer listener com-plaints, and it will enable thestation engineer to become moreproficient in the operation of his an-tenna system.

Fig. 8. Poor maintenance has alloweda wooden cable support to collapse.

February, 1968 35

PALACE...where tffe new RE15was born!

OThe biggest names in show. business play the Hollywood

Palace on ABC-TV. They demand thefinest sound possible. And they get itfrom the new Electro-Voice RE15. It'sno accident, and here's why: ABC-TVsound engineers worked with us foralmost two years perfecting the REIS.Their demands reflected the problemsthat make TV variety programs one ofthe toughest assignments for any soundengineer.

Small in SizeThey asked for a small, light micro-

phone. The REIS is shorter than a pencil,with a body no thicker than a CannonXL connector. And it weighs just 8

ounces. Perfect for a fast-moving boomor for hand-held applications.

Flat Off -Axis ResponseABC engineers requested the same

response curve off axis as on axis. Witha big band in the same studio, some bandpickup from the back of the solo micro-phone would be inevitable. It wasn'teasy to make this "off mike" pickup assmooth, flat and wide range as the on -axis response, but that's exactly whatthe REIS has to offer at every angle.

Super -Cardioid PatternBut the next request almost stumped

us. They asked for wide front pickup,so that a boom operator could easily"work" two or more performers, yetthey wanted the RE15 dead at the rearfor longer "reach". In short, a polarpattern similar to a ball sliced neatly inhalf! And that's almost what they got.

The REIS is down only 3 db at 80° offaxis (in any plane) and just 8 db at 90°.But at 120° and 180° the level drops over19 db, and at 150° the RE15 response isalmost 26 db below the on -axis level.This super-cardioid pattern (with a smalllobe at the back, 15 db down) provedmuch more useful than a classic cardioid.With the microphone tipped 30° (a

L to R.: Robeft Cra,ford, Chief Utility; Eric Chief BoomOperator: Eugene Luk,Jwski, Technical Director; John 'deal, AudioEngineer, for ABC's Hollywood Palace.

typical boom or stand operating posi-tion) the area of greatest cancellation isoriented directly at the sources of un-wanted sound-the audience and thesound reinforcement speakers.

E -V ReliabilityABC-TV also demanded plenty of

output. They got it. A crisp -55db. Andthey got the reliability and ruggednesstypical of all E -V professional dynamicmicrophones, as well. Famous E -VAcoustalloy® diaphragm plus multipledust and magnetic filters assured un-changing response and sensitivity. Plusa "bass tilt" switch to cure boomyacoustical problems.

The slotted "backbone" of the REISidentifies it as the latest in the Electro-

Voice series of Variable -D® and Con-tinuously Variable -D® microphones.

It's very possibly the mostsignificant achievement

of them all. Write foryour copy of

Microphone Facts that givall the details. And, for animpressive demonstration of RE1capability, find a TV set with reallygood audio, and tune to the HollywoodPalace on ABC-TV, any Saturday night.Or match the REIS with your own list ofdemands. We think you'll agree that astar was born on the Hollywood Palace!

FREE! Any E -V professional microphone willbe repaired without cost if it fails in the firsttwo years-regardless of cause. That's right,repairs are free for the first two years ... noquestions asked!

ELECTRO-VOICE, INC.Cecil Street, Buchanan, Michigan 49107

A SUBSIDIARY OF GULTON INDUSTRIES, INC.

high fidelity speakers and systems tuners, amplifiers, receivers public address loudspeakers microphones phonograph needles and cartridges organs space and defense electronics

THE TWO -TOWER TEST

by Robert A. Jones*

Directional antennas are not quite as complicated as

they seem; the method of analysis makes a difference.

Although some operators at one-tower stations may question use ofthe word "simple," the simplest di-rectional antenna is the two -towerarray. And, while it may not beobvious, any combination of towers,even or odd in number, can be bro-

*Consulting Engineer, LaGrange, Ill., andBE Midwest Regional Editor.

ken down into combinations of two-tower arrays. The method is analo-gous to algebraic factoring, thebreaking down of a complex expres-sion into a combination of simplerparts.

Theory

Fig. 1 shows how a pattern fromthree towers in line can be consider-

?A)113) ICI

/A3'

0

E2 /A2' 20 F2/4'2 3 F3/ 03

1/0 10 1/0 1 0 1 /0

E2 /021 F2 /02 4_ F3 /A3

E3/A3' F2 13 /02 +03

TOWER 1 IS ALWAYS REFERENCE, OR UNITY

)NOT TO SCALE)

ed to be produced by two two -towerarrays. Adjacent to the final patterncan be seen the two component pat-terns which form it. The patternsmust be expressed in what is knownas the "multiplication" form.' Ascan be seen, two -tower pattern B ismultiplied by two -tower pattern Cto produce three -tower pattern A.Further, it can be seen that whereverone of the two -tower patterns has anull, the three -tower pattern alsohas a null. The same is true forlobes.

The foregoing method may becarried one step further. Fig. 2shows an approach to a four -towerfinal pattern. Three two -tower basicbuilding blocks are used. In general,the number of two -tower basic pat-terns will be one less than the totalnumber of towers; this is reasonable,since the reference tower is commonto all. The same facts hold true forthe four -tower array as for the three -tower case: At each azimuth whereone of the basic patterns has a nullor a lobe, the final pattern will alsohave a null or lobe. The same prin-ciples may be applied to systems offive, six, or even more towers.

It should be noted that in eachof the above cases the towers havebeen assumed to be in a straightline. This is commonly referred toas the "in -line" array.

Fig. 1. Multiplying two two -tower patterns gives three -tower result (left).' See Carl E. Smith, Theory and Design of Di-

rectional Antennas, Cleveland Institute ofElectronics, 1951, p2-1-36.


A special case of pattern multipli-cation is shown in Fig. 3. Again,two two -tower patterns are involved,but this time a different result is ob-tained when they are multiplied. Asthe reader can see, the end resulthas four towers, not three, and thefinal pattern is not symmetericalabout the line of towers as was thecase in Fig. 1.

Careful inspection reveals that inFig. I both two -tower patterns hadtheir tower lines oriented the sameway. This is not so in Fig. 3. Whenthe two basic pairs do not havethe same orientation and/or spacing,the resulting array has four towersinstead of three. In fact, the three -tower array may be considered afour -tower array, with the two mid-dle towers identically located (orone considered to be on top of theother). For example, if the towerlines in Fig. 3 are rotated toward thesame bearing, the two middle towerswill move closer and closer togetheruntil they merge.

Certain facts about the two -towerbasic pattern should be reviewed be-fore proceeding. A two -tower pat-tern from close -spaced (less thanhalf -wave spacing) towers can haveno more than two nulls. These arespaced equally with respect to thetower line, and they are of equal

depth. For example, if there is a

null 20° to the right of the towerline, there will be a similar null 20°to the left. And, if one of these nullsis "pulled" down to zero signal, theother will be brought to zero also.Keep in mind, of course, these arethe theoretical conditions, and whenthey do not work out in practice, itcan mean something is wrong withthe array.

Practical Applications

The "factoring" of an array intotwo -tower elements may be used asa tool in adjusting and maintainingthe typical directional antenna. Oneof the most common uses of the two -tower pattern as a testing device isin the calibration of meters andphase monitors. If there are twotowers-or any number-and it is

desired to compare the proportionalradiation from each, this testingtechnique may be used. Logically,one assumes that if the base cur-rents are equal and the towers arethe same height, the radiations areequal. This is not always the case, aswas discovered while tuning theantenna of WRHL, Rochelle, Illi-nois. In fact, at WRHL it was nec-essary to introduce some 15%more base current into the center

tower to achieve equal radiations.Our method of checking for equal

radiation is to place a co-worker, ina car with two-way radio, about oneor two miles from the transmittersite directly in line with the towers.Normally he is close enough to veri-fy his position on the tower linevisually. (In some cases this is easierto do at night by lining up the towerlights.) This operator watches hisfield -intensity meter as we tune fora lower and lower signal. When wehave achieved the lowest possiblesignal, usually around 0.1 my/m,we know the radiations from thetwo towers are equal and in phaseopposition along the tower line. Byreading the base currents underthese conditions, we can uncoverany slight differences in radiation.And, as we found at WRHL, dif-ferences sometimes are found. Thisis true even when all the tower base -current meters previously have beenconnected in series at one point. Asa general rule, however, equal basecurrents mean equal radiated fields.

In cases of multiple -element ar-rays, each pair of towers can bechecked, one at a time, if for anyreason it is thought the radiationsare not directly proportional to thebase -current ratios. As the heightof the towers approaches one-half

11.111

(A)

40 ELI/ 4i4 i30 E3/ 13/

20 E2 02/10 I LI_

2

1

(B) (C)

F2/ 2 3 F3/4)3

/1_ 1 LLD_

(NOT TO SCALE)

(D)

4 F4 / 4

1 1LS)_

Fig. 2. Pattern of four -tower in -line array at left is result of three two -tower arrays with the same orientation.

February, 1968 39

wavelentgh, the likelihood of dif-ference in base current increases.If towers of unequal height are used,it is absolutely necessary to conductthe above test.

The same test is used to checkfor instrumentation errors in thestation phase monitor. If two tow-ers 90° apart are assumed, a theo-retical phase difference between thetwo of 90° is required to producea null on the tower -line bearing. Ifthe null is reduced to a minimumand the phase monitor reads, say,93°, an error of +3° exists betweenthis particular pair of towers. Withother than 90° spacing, the theoreti-cal phase must equal the differencebetween the actual spacing and180°.

In a like manner, each pair oftowers can be checked, one at atime, to discover any individual er-rors in phase angles. This can alsoshow up errors in the remotely in-dicated tower -base currents. Thesephase -angle and current -ratio er-rors can then be introduced into thetheoretical pattern parameters as astarting point in tuning the antenna.

Certain precautions must be takenin order not to be misled while mak-

ing these tests for errors. First. inmost cases it is wise to use morethan one location along the line oftowers for "talking down" the null;then average the base currents, re-mote currents, and phase -angle er-rors found. The reason for this isthat any one field location can beaffected by some local phenomenon.If, however, there are wide varia-tions in, say, two or three points,other troubles may be present. Onepossibility, of course, is instabilityin the metering, but a more likelycause is severe reflections.

Another use of the basic two -tow-er pattern is in identifying reflect-ing objects. This is done as follows.Determine the bearing from the sta-tion to the suspected object orsource of reflections. Then, usingthe two -way -radio car, adjust thetwo -tower pattern for a null at thisazimuth; if there is no signal inthe direction of the reflector, therecan be no reflections. Then drivearound to the other side of the pat-tern and check for a symmetricalnull. Two equally deep nulls indi-cate no serious reflections, or thatunder these conditions the reflectingobject lies in the null. (See "The

`Hot' Water Tank at WJIL," byRobert A. Jones, January 1963BROADCAST ENGINEERING, page 19.)

In some instances, it may not beknown whether any reflecting ob-jects are in the vicinity of an array.To check for this, one can set upa null, say 40° off the tower line,and tune for minimum. Then thedepths of this and the companionnull are compared. If they are simi-lar, there are no reflections. Addi-tional checks can be made at, say,60 and 80° to give a spread angle.This approach also will reveal de-formities in the ground system, ornoncircular tower radiations. All ofthese conditions can result in ameasured pattern that is not in ac-cord with the predicted one.

Conclusion

It is easy to become confused bythe complexity of many of the multi -

element directional antennas in usetoday, and by the high-poweredmathematics involved in their com-putations. However, the total arraycan be understood, if it is realizedthat each is composed of basic two-tower building blocks which canbe taken one at a time.

2 F2 /b2

1 4

1/0 F4 //th4

/3

1 LSI

3

F3 / 3

(NOT TO SCALE)

1

Fig. 3. Nonsymmetrical four -tower patterr from multiplying patterns of two -tower arrays with different orientations.


The Shure SM58 self-windscreened unidirectional micro-phone is ideal for broadcast uses such as remote news,sports, interview and vocal recordings because it elimi-nates or minimizes the irritating "pop" caused by ex-plosive breath sounds. With the SM58 you will have thepeace -of -mind assurance that you're delivering the qualityaudio that goes with pop -free pickup. It's great for studioannouncing, too-or wherever the announcer or vocalisthas the audio -degrading habit of "mouthing" the micro-phone. Of course, the same filters that eliminate pop alsodo away with the necessity for an add-on windscreen inoutdoor uses.On the other hand, the unusually effective unidirectionalcardioid pickup pattern (uniform at all frequencies, in allplanes) means that it is a real problem -solver where back-ground noise is high or where the microphone must beoperated at some distance from the performer. Incidentally,

SHV. E.

THIS MICROPHONESUPPRESSES "POP"

...EVEN IN THETIGHT CLOSE-UP"DANGER ZONE"

but very important, the SM58 tends to control the lowfrequency "boominess" that is usually accented by close-up microphones.All in all, close up or at a distance, the Shure SM58 solvesthe kind of ever-present perplexing problems the audioengineer may have felt were necessary evils. The SM58might well be the finest all-purpose hand-held microphonein manufacture today. And, all things considered, it is

moderate in cost.Other features: the complete pop -proof filter assembly isinstantly replaceable in the field, without tools. Filterscan be easily cleaned, too. Stand or hand operation. De-tachable cable. Rubber -mounted cartridge minimizes han-dling noise. Special TV -tested non -glare finish.For additional information, write directly to Mr. RobertCarr, Manager of Professional Products Division, ShureBrothers, Inc., 222 Hartrey Ave., Evanston, Illinois 60204.

SELF-WINDSCREENED UNIDIRECTIONAL DYNAMIC MICOPHONE

OTHER SHURE PROFESSIONAL MICROPHONES .. . FOR SUPERIOR AUDIO

MODEL SM5

CAPDIOID BOOM DYNAMIC

Because its cardioid directionalpattern is uniquely uniform withfrequency and symmetrical aboutits axis, the SM5 is singularly in-dependent of the effects of en-vironment. Even in extremeshooting situations (such as withtight sets, low ceilings, hard walls,low microphone angles, traffic orair -conditioner noise and rumbleand changing distance) the SM5minimizes sound coloration andambient noise pickup.

MODEL SM76

3/4" OMNIDIRECTIONALDYNAMIC

Ideal for interviews andaudience participation,yet unusually smoothwide range response (40-20 KC) for critical musicreproduction. Instantlydetachable from stand.Steel case with Cannonconnector.

MODEL SM50

OMNIDIRECTIONAL

DYNAMIC

Self-windscreened andpop -free for news, sports,remotes, and interviews.Also ideal for many stu-dio and control room ap-plications. Comfortablybalanced for hand orstand use. Natural re-sponse.


February, 196841

a

sound

investmenfor the BroadcastIndustry...

REMOTE CONTROLMIKE REELS

Specially designed reels. Remotecontrol by drum, push button orstation relay. 115 volt reversiblechain driven motor. 2 to 8conductor slip rings available.150' cable capacity.

POWER CABLEREELS

I.E.R.'slevel windPort -O -Reelsprotect andprevent mikeor extensioncord break-downs. Up to400' cablecapacity.

Write for Specification Data on themost complete line of RemoteControl Reels and Port -O -Reels.

INDUSTRIALELECTRIC

INCORPORATED

INDUSTRIAL

ELECTRIC

REELSINCORPORATED

1503 CHICAGO ST.OMAHA, NEBRASKA 68102

Dropout(Continued from page 24)

operation of these devices is demon-strated in Fig. 2. A shear -mode ce-ramic transducer, A, is bonded toglass blank B and driven with electri-cal energy at or near its resonantfrequency. This generates a sonicvibration which travels through theglass to surface C, where it is reflect-ed to D, then back to ceramictransducer E. At E, the sonic energyexcites piezoelectric current, whichis amplified to recover the originaland now delayed signal.

The glass blank is made withspecial modifiers which give it azero temperature coefficient at ap-proximately 30°C. The blank is sev-eral wavelengths thick.

Special design features optimizethe performance of these devices forhandling a television signal. One ofthe two glass memories is designedto handle the 3.58 -MHz chromi-nance information directly. It pro-vides necessary response p 1 u sfreedom from spurious reflectionsover the chroma bandwidth of 2MHz to 4.2 MHz, as required forNTSC color. The other memory de -

Fig. 2. Blank of special glass formsheart of the acoustical delay lines.

lays the luminance information ata carrier frequency of 10 MHz.(Acoustic delay lines cannot be de-signed to operate below 1 MHz.Thus, a carrier system is necessaryfor the luminance information.)

Adequate sync and blankingresponse to preserve timing relation-ships is the criterion for the lumi-nance -channel response. Above 2.5MHz, all energy must be removedfrom the luminance signal pro-cessed by the color channel. Other-wise, edge interference between thephase -corrected color and the lumi-nance is apparent in the delaymaterial.

The chroma signals (2.3 to 4.2MHz) can be delayed directly, sinceglass delay lines can be designed tooperate in this frequency range. Thetotal delay time for the chromasignal is trimmed by a variable delayline. Incorrect total delay time of thechroma signal shows as a change inthe hue of the fill-in material. Thechroma signal, inverted 180° inphase, is added to the delayed lumi-nance signal and applied to the de-layed -video input of the videoswitch.

System Performance

A properly designed and operateddropout compensator detects andcompensates not only the gross drop-outs producing the high -contrastflashes, but also the dropouts oflesser amplitude that appear in high -saturation color signals due tochanges in recorder equalization.The speed of switching action is suchthat the switching transients are pastthe response limits of standard tele-vision systems. These factors, to-gether with the relatively wide -band-width luminance and full -bandwidthcolor fill-in material, produce asystem that makes it virtually impos-sible to see compensated dropoutson a random basis. In addition, fullcompensation during the sync inter-val eliminates time -correction errorsand servo instability caused by drop-outs. When such compensation isachieved, useful tape life is extendedand program quality is improved.

The contributions of B. A. Holm-berg, I. Moskowitz, R. R. Barclay,and K. E. Williams to the informa-tion on which this article is based aregratefully acknowledged.

(References are listed on page 24.)

42Circle Item 16 on Tech Data Ca rd


February 1968

We interrupt this magazine to bring you. .

Late Bulletin from Washington

by Howard T. Head

Latin American Interference Below Expectations

AM radio in Central and South America has experienced rapid growth in recent

years. Not only have many new stations gone on the air, but there have been

an increasing number of reports of stations operating with powers ranging

as high as 1000 kw. This operation, which is often undertaken on the same

frequencies assigned to United States Class I -A clear -channel stations, has

become a source of concern to American broadcasters and the FCC.

Surprisingly, in many instances interference levels received in the U.S.

from these high -power stations have been considerably less than those pre-

dicted from established curves of skywave field strength vs distance. This

has proved true even in cases of high -power operation in countries as close

to the U.S. as Costa Rica, Surinam, and even Cuba (see April 1967 Bulletin).

Additionally, reports indicate that mutual interference between stations in

the United States and Mexico is often less than expected.

All of these situations involve skywave propagation over predominantly

north -south paths. Authorities point out that north -south propagation should

be different from east -west propagation, although there is little agreement

as to the nature and extent of the difference. Existing skywave curves are

based on recordings made over predominantly east -west paths, and few, if any,

recordings applicable to north -south propagation are available.

The Commission is considering the possibility of establishing a research

program to obtain skywave recordings over north -south paths, and to analyze

the data with the view toward preparing new skywave curves. The 1967-1968

FCC budget includes $600,000 for research studies, essentially none of which

has yet been committed.

Satellite -to -Home Broadcasting Shows Little Progress

Plans for a domestic satellite system for radio and television relaying await

the report of a special Presidential Study Committee (see October 1967

Bulletin); meanwhile, there continues to be much talk and little progress in

the development of space satellites for radio and television broadcasting

directly to homes. NASA has awarded some study contracts for investigation

of the feasibility of direct shortwave and FM radio broadcasting to homes,

but satellite -to -home television broadcasting remains in the early study stages.

Numerous technical problems are involved. One of the more important is thefact that a television broadcasting satellite will require substantial amountsof primary power -- variously estimated as ranging up from 1 Mw to 5 Mw --in order to provide good -quality television pictures to large areas. Ofequal importance is the difficulty of finding available television channels,even in the UHF band. Sharing of channels between space and ground broad-casting stations would cause intolerable interference, and the demands forspectrum space make it unlikely for exclusive space -broadcasting channelsto be made available through reallocation.

In addition to the technical problems, there are obvious political problemsrequiring a high degree of international cooperation. Until a way is pointedto a solution of technical and other problems, direct satellite -to -homebroadcasting will remain little more than a concept.

Commission Gropes for Solution to Land-Mobile Problems

In the face of mounting pressures from the land mobile services, the Com-mission is intensifying its search for ways to make additional channelsavailable for land mobile use (see January 1968 Bulletin). Special studycommittees are considering several possibilities, including sharing of theVHF television channels with land -mobile users, similar sharing of UHF tele-vision channels, and the outright diversion of a group of UHF televisionchannels. If UHF channels are to be diverted, the land -mobile groups wouldprefer the frequencies immediately above the lower end of the UHF televisionband (470 MHz), but these channels have the highest occupancy by televisionstations. At the upper end of the UHF television band, immediately below890 MHz, Channels 70-83 are occupied by literally thousands of UHF televisiontranslators.

No entirely satisfactory solution to the problem is evident. It appearsunlikely that any compromise can be worked out which will be fully acceptableto both the broadcast and land -mobile interests.

Short Circuits

The Supreme Court has agreed to hear the case which upheld the liability ofCATV operators for the carriage of copyrighted program material (see July1966 Bulletin). . .The only pay -TV station in operation, an experimentalgrant at Hartford, Connecticut (see September 1967 Bulletin), is discontinuingoperation. . .The Commission continues to levy frequent and heavy fines onlicensees for rule violations -- common infractions include failures tomake equipment -performance measurements and daily inspections, and the latefiling of license -renewal applications.

. .The Commission has extended thetesting period for FM broadcast stations (see June 1967 Bulletin). . .TheFirst Circuit Court of Appeals has vacated a Commission order forbidding aMaine CATV system from carrying Canadian programs prior to their showing inthe U.S. (see June 1967 Bulletin).

Howard T. Head. . . in Washington

these connectors aren't just accessories!And-ew is one of the world's largest manufacturers of RE connectors. Our engineers develop

connectors not just as accessories but as part of complete antenna, cable and transmission

line sysiems. Be sure of proved performance and reliability. Contact your regional Andrew sales

engineer or write Andrew Corporation, P. 0. Box 807, Chicago, Illinois, U.S.A. 60642.

C O R P O R ATIO N29 YEARS OF ENGINEERING INTEGRITY

Circle kern 17 on tech Data CardFebruar}, 1968

45

TheInternational

Set.Conrac watches television in about a hundred languages.Japanese, Thai, Swedish, Norwegian, Hebrew, French,German, you name it. In fact, just about every majorTV broadcaster in the world uses Conrac monitors.Except the Russians. (But, you know how that is.)

conrac

NEWS OF THE INDUSTRY OE ItlINTERNATIONAL

TV for the Bahamas

The forthcoming inaugurationoftelevision service in the Bahamas hasbeen announced. Intended to serveeventually more than 90% of the Is-lands' population of about 100,000,three phases of the Government'sseven -phase plan will be implementedimmediately, concurrent with plans torevamp and extend present radio ser-vices.

IN INI ME IM IM

Award of the three-phase projectimplementation, plus the revamping ofradio facilities, operations, program-ming, etc., has been made to N. J.Pappas & Associates, Montreal. Com-pletion of the main network produc-tion center at Nassau is expected byearly 1969.

The system will include AM andFM radio, a television network center,television distribution, rebroadcast fa -

MI MO MI IN

Multiple Cartridge Playback Units

w

***as; ;;;-****** rs*-Ten Spot Model 610B

0 0 0 0 ,0 0 0 0 0 0

Five Spot Model 6055

... bringing a new dimension topushbutton broadcastingSpotmaster Ten Spot (holding 10 cartridges) and Five Spot (holdingfive) will reproduce any NAB Type A or B cartridge instantly at the pushof a button ... at random or in sequence. They may be operated manuallyor incorporated into programmed automation systems, using one, two orthree NAB standard electronic cueing tones.

The Ten Spot is designed for 19" rack mounting while the Five Spotis available either in an attractive walnut -finished case or with a 19" frontpanel containing a cartridge storage cubicle. Both are backed by Spot -master's iron -clad full -year guarantee.

For further information about these and other Spotmaster cartridge tapeunits, call or write today. Remember, Broadcast Electronics is the No. 1designer/producer of broadcast quality cartridge tapeequipment ... worldwide!

BROADCAST ELECTRONICS, INC.e=

8810 Brookville Road, Silver Spring, Maryland 20910; Area Code 301, 588-4983

cilities, ETV, and all related require-ments. Initially, the television systemwill be monochrome, with provisionfor the later addition of color. All Ba-hamian broadcasting facilities will becommercial, under the jurisdiction ofthe Bahamas Broadcasting and Tele-vision Commission. The Commissionpresently operates two commercialAM -FM facilities designated ZNS-1and 2, operating at 1540 kHz, 1240kHz, 107.2 MHz, and 107.9 MHz.

NATIONAL

New Cable Plant

Completion of a new coaxial -cableplant at Sherrill's Ford, N.C. wasscheduled for January by SuperiorCable Div. of Superior ContinentalCorp. The 50,000 square -foot produc-tion facility, a one-story, steel -framebrick building, will incorporate 3000square feet of air-conditioned officespace as well as 2000 square feet ofstorage and shipping space in additionto the manufacturing area. The plantsite includes approximately 44 acres.A dam 1100 -feet long was constructedto create an 11 -acre lake for plantfire protection; the lake and surround-ing watershed area will be further de-veloped following plant completion.

Distributorship Ended

Philips Broadcast Equipment Corp.has agreed to the termination ofthe Visual Electronics Corp. exclusivedistributorship of Norelco color cam-eras, due to a projected overlap of themanufactured product lines and mar-ket activities of the two companies.

According to the announcementmade by Visual, both companies planthe early introduction of new TVtransmitters, audio product lines,closed-circuit television equipment,and color -television equipment. Visualhas undertaken a program for develop-ing its own color camera line, which isexpected to be ready for the fall 1968program season.

Opens Sales Office

A Minneapolis office serving Min-nesota, North and South Dakota, andportions of Iowa and Wisconsin hasbeen opened by Memorex Corp. LaryL. Lindsey, formerly working out ofthe Memorex regional office in Chi-cago, has been named to the new of -


z

a

F-

2, FULLY

EQUALIZED

HOW KAPPA GETS VIDEO CABLE

PERFORMANCE... WITHOUT CABLE

We replace it! ... with Kappa Super -1l Delay Lines..As a result we canhelp you avoid large coils of video cable, storage compartments, andseparate equalizers. Kappa Super-rj Delay Lines outperform conventional(m -derived) lines because they are more efficient ... they yield inherentlygreater delay -bandwidth from fewer components. The performance of KappaSuper -1 more nearly approaches constant delay at all transmitted frequencies... an essential characteristic of the ideal low pass, dispersionless delay line.

Unit -to -unit uniformity and excellent temperature stability are alsomarked features of Kappa Super-rj Video Delay Lines.

Where you need equalized cable performance without physical lengthin your video systems, do the job efficiently and economically ... use KappaSuper -1l Delay Lines!

ACTUALSIZE

I

I III I I

I I

KAPPA SUPER -I1 VIDEO CABLE SIMULATOR GUIDE

Length of Package Approx. Max.Cable Length Delay Insertion

Simulated* (x '1a" Range LossModel No. (In feet) square) (nsec.) (db) Price**

10A50 50 5" 78 0.5 $52.75

10A100 100 8" 157 1.0 $69.50

10A150 150 11" 2 35 1.5 $86.25

10A200 200 14" 314 2.0 $103.00

10A250 250 16" 392 2.5 $119.75

-1-2 ft. or 2°/a, whichever is greater. "Additional discounts available for quantity orders.

SPECIFICATIONS OF KAPPA SERIES 10A SUPER-i DELAY LINESImpedance: 75 ohms Size: '/8" square x length requiredK factor: less than 0.25% for sin' T Pulse Case material: Electro-tinned brassCross talk: less than 46 db finish: Mil specgray lacquer

For prompt engineering assistance call us collect at (201) 541-4226

APPA NETWORKS, INC.Delay Line Specialists Manufacturing Engineers

165 ROOSEVELT AVENUE CARTERET, NEW JERSEY 07 008 TEL (201) 5 41-4 2 2 6World's largest manufacturer of broadcast quality delay lines.


February, 1968 49

TELECT E N '3 -in -1 Versatility!

Self -Contained Production Center Compact Lecture Console Overhead Camera SystemTELECTERIV ... for instructorswho want the advantages of TVteaching without the extra workand time usually involved.Rehearsals and special prepara-tion are reduced to a minimum,because the instructor handlesall the controls. He can switchup to five video sources, adjustillumination, control the 10:1zoom lens, show slides, super-impose the TELECTERNI* videoover any other input source -all the while giving a relaxed,smooth, protessional presenta-tion at a pace he sets himself.

Any type of instruction - inindustry, the military, andmedicine, as well as in schools,colleges and universities -can be made more effectivewith less distress; usingTELECTERN"'

Trademark. TeleMation, Inc.

Write for complete details - request Form TPB-110

Television Equipment for Education, Industry and Military . . .

...911011

MULTICASTER

VR 660 Video Processor

PORTA SYNC

2.1 Interlace Sync Generator EIA Camera Control

.... from TeleMation - where experience powers pacesetting products!

0 T M2275 So. West Temple Salt Lake City, Utah 84115Te ephone (801) 486.7564

fice. The office is located at 7710 Com-puter Avenue.

Industry Outlook Good

The broadcasting industry shouldsee a resumption in 1968 of vigorousgrowth in sales and earnings, accord-ing to an industry survey by Good-body & Co. Commercial broadcastinggains, along with the general economy,slowed in 1967, but are expected toaccelerate in coming months. This ex-pectation stems from the fact that allsigns point to improvement in generaleconomic activity this year and thatthis improvement should lead to high-er expenditures for advertising, thebroadcasting industry's principalsource of revenue. Advertising outlays,Goodbody believes, can rise about 7%in 1968, as compared with a gain ofabout 3% in 1967 over 1966.

The industry's revenues now totalover $3 billion annually, and the endof their rise is not in sight, accordingto the study. Color broadcasting isexpanding rapidly, regular internation-al exchange of programs via satellitetransmission is in the offing, while thegrowth of community antenna televi-sion, educational television, and evenpay TV should stimulate, rather thanhinder, the industry's progress.

ORGANIZATIONSIEEE

Dr. S. W. Herwald, vice-president,electronic components and specialtyproducts group, Westinghouse ElectricCorp., has been elected president ofthe Institute of Electrical and Electron-ics Engineers. He succeeds Walter K.MacAdam, vice-president, governmentcommunications, American Telephoneand Telegraph Co.

The board of directors also an-nounced the election of Lynn C.Holmes, assistant to the vice-president,research and engineering, General Dy-namics Electronics Div., as a vice-president.

A Fellow of the IEEE since 1960,Dr. Herwald will become the organi-zation's fifth president since it wasformed in 1963 by the merger of theAmerican Institute of Electrical Engi-neers (AIEE) and the Institute of Ra-dio Engineers (IRE). AIEE was found-ed in 1884 and IRE in 1912.

Born in Cleveland, Dr. Herwald re-ceived his BSME from Case Instituteof Technology in 1938, and his MSMEin 1940 from the University of Pitts-burgh. In 1944, he completed ad-vanced studies at- the University ofPittsburgh and received a doctor's de-gree in mathematics. He joined West-inghouse in 1939, and early in his

Circle Item 20 on Tech Data Card50 BROADCAST ENGINEERING

career he specialized on technicalproblems in the ordnance field, par-ticularly in servomechanism develop-ment.

In 1952, Dr. Herwald was namedengineering manager of the air armdivision at Baltimore, and four yearslater he was appointed manager of thedivision. In 1959, he was elected avice-president of Westinghouse incharge of research and development.

He has been active in the AmericanSociety of Mechanical Engineers andthe American Institute of Aeronautics.He is a member of the National Acad-emy of Engineering and also a mem-ber of the Executive Committee of theAir Force Scientific Advisory Board.

NAB

The Broadcast Engineering Confer-ence Committee of the National As-sociation of Broadcasters has approvedpreliminary plans for next year'sBroadcast Engineering Conference tobe held as part of the 46th annual con-vention in Chicago.

The committee approved the ap-pointment of two subcommittees toselect conference luncheon speakersand the recipient of the annual En-gineering Achievement Award. It alsosifted through proposed topics of en-gineering papers to be submitted dur-ing the conference.

Albert H. Chismark, director ofengineering for the Meredith Broad-casting Co., Syracuse, N.Y., and chair-man of the Conference Committee,will head up the five -member AwardsSubcommittee. Other members areWilliam S. Duttera, director of alloca-tions engineering, National Broadcast-ing Co., New York; George Jacobs,engineering director, CorinthianBroadcasting Co., New York; JamesD. Parker, staff consultant on telecom-munications, Columbia BroadcastingSystem Television Network, NewYork; and Robert J. Sinnett, vice-presi-dent for engineering, WHBF AM -FM -TV, Rock Island, Ill.

Leslie S. Learned, vice-president forengineering of the Mutual Broadcast-ing System, New York, was namedchairman of the Luncheon SpeakerSubcommittee. Named to serve withhim were LeRoy Bellwood, chief engi-neer of KOGO-TV, San Diego, Calif.;Clure H. Owen, manager of alloca-tions, American Broadcasting Co.,New York; John T. Wilner, vice-presi-dent for broadcast engineering, TheHearst Corp., Baltimore, Md.; andBenjamin Wolfe, vice-president for en-gineering, Westinghouse BroadcastingCo. (Group W), New York, N.Y.

Members of the two subcommitteescoilnprise the membership of the fullConference Committee.

All Digital ColorSync Generator

Exclusive Features - All pukes and transitions cicick derived No moiostables - no delay lines IntegrEted circuit reliability Dual outputs - permit pulse assignment with

full stgndby Subcarrier vs. horizontal jitter better than

0.25 nsec. Pulse Otter better than 4 nsec throughout frame 13/4" rack space - including all "Add -In"

modules

Prices and specifications subject to change without notice.

Add -In Modules - Monochrome Genlock Bar Dot Generator Color Genlock Sync Changeover Switch

MonochromeModel TSG-2000M

$1,000ColorModel TSG-2000C

$1,500

New poIrA-gYNCTMIdenticalPerformanceat a GreatSavings!

Pat. Pending

PORTA-SYNC"

NIA SYNCHRONIZING GENERATORhiC GE, 50 ItY,

Ideal for .. REMOTE FIELD APPLICATIONS ...PORTABLE TEST GENERATOR ... SYSTEM SPARE... FULL TIME DUTY. Economical, yet absolutelyno sacrifi:e of waveform performance.Specifications are the same as ModelsTSG-2000M/C, but Add -In modules are notavailable because of ultra -compact dimensions of31/4" h x 51/4" w x 10" d.

MonochromeModel TSG-1000M

$695ColorModel TSG-1000C

$1000For complete details, request Form TPB 30 Prices and specrications subject to change without notice

fr3m TeleMation - where experience powers pacesetting products!

TELEM TION,2275 So. West Temple / Sal Lake City, Utah 84115Telephone (801) 486-7564

February, 1968Circle Item 21 on Tech Dcto Card

51

ALLEN AVIONICS "HF" SERIESture stability, excellent phase linearitythan adequate electrical replacementseliminated. Standard impedances areinput & output connections & canspecs. Other time delays available.time, ask about our "HR" &"VHR" Delay Lines.WRITE FOR CATALOG

is an extremely high quality group& low pulse distortion characterize

for coaxial cable. The inconvenience50 & 75 ohms. Units are normally

be supplied with taps to yourFor longer delays with fast rise

of Delay Lines. Superior tempera-this group, making them moreof handling & storing cable is

furnished with BNC connectors for50/1 RATIO

ATTENUATION 9 db MAXIMUMSIZE: 21/2" x 41/40 x 12075/1 RATIO

ATTENUATION 12 db MAXIMUMSIZE: 31/20 x 41/2 x 1 20 Time Delay

Micro-Rise Time

NanosecondsBaddwidUi

(3d1)100/1 RATIO Time Delay Rise Time Bandwidth

seconds Maximum Megaeyelles

.5

.6

.7

.8

.91.01.25

10121416182025

36.030.025.722.520.018.014.4

ATTENUATION 15 db MAXIMUMSIZE: 41/2" x 51/2" 15"

Micro- Nanosecondsseconds Maximum

(3db)Megacycles

Time DelayMicro-

seconds

Rise Time BandwidthNanoseconds (3db)

Maximum Megacycles

2.02.252.502.75

26.73033.436.7

13.512.010.8

9.83.0 30 12 3.0 40 9.0 1.5 30 12.03.25 32.5 11.1 3.25 43.3 8.3 1.75 35 10.33.5 35 10.3 3.50 46.7 7.7 2.0 40 9.03.75 37 5 9.6 3.75 50 7.2 2.5 50 7.24.0 40 9 4.0 53 4 6.75 3.0 60 64.25 42.5 8.48 4.25 56.7 6.35 3.5 70 5.154.5 45 8 4.50 60 6.0 4.0 80 4.54.75 47.5 7.58 4.75 63.4 5.7 4.5 90 4.0

ALLEN AVIONICS, INC. Division of A. K. ALLEN CO., Inc. 255 E 2nd ST., MINEOLA, N.Y.11501


CF2 ULTRASONICCLEANER for

MOTION PICTURE FILM

Presented The Academy of Motion Picture Arts andSciences Award of Merit for Outstanding Technical

Achievement.ext-tr*,0=tr,

Ultrasonic energy is the most effective and economical way to thoroughly andrapidly clean motion picture film without mechanical scrubbing and wiping. Thecold boiling effect (cavitation) of ultrasonic energy performs the entire opera-tion. Only the solvent touches the film and a forced air, flash dry -off removes allsolvent and residue.

Restores clarity and sound to maximumquality.

Enhances the entertainment value ofmotion picture film and improves com-mercials.

Assures static free film with color bal-ance undisturbed.

Cuts projector maintenance costs . .

no dirt or dust carried into gates andorifices . . . less breakdowns.

Completely automatic ... requires onlyloading and unloading.

Costs only 1 20 of a penny per run-ning foot to operate.

Used by every major motion picture labin the world.

DESCRIPTIVE BROCHURE WILL BE SENT ONREQUEST.

Patents

USA -2,967,119 Luxembourg -37,634Belgium -582,469 Great Britain -909,421France -1,238,523 Other World Pats. Pend.

LIPSNER-SMITH CORPORATION7334 No. Clark St., Chicago, III. 60626

Telephone: 312-338.3040Circle Item 23 on Tech Data Card

4

Mom

6

.t.

on

SMPTE

The following officers have beenelected for two-year terms, 1968 and1969. Engineering Vice -President -William T. Wintringham, Bell Tele-phone Laboratories, Holmdel, N.J.; Fi-nancial Vice -President - Joseph T.Dougherty, E. I. du Pont de Nemoursand Co., Inc., Clifton, N.J.; SectionsVice -President -Wilton R. Holm, E. I.du Pont de Nemours and Co., Inc.,Burbank, Calif.; Vice -President for Ed-ucational Affairs - D. Max Beard,Naval Ordnance Laboratory, Washing-ton, D.C.; Vice -President for Instru-mentation and High -Speed Photogra-phy Affairs - William G. Hyzer,Consultant, Janesville, Wis.; Vice -Pres-ident for Motion Picture Affairs -Richard J. Goldberg, Houston FearlessCorp., Los Angeles, Calif.; Vice -Presi-dent for Photo -Science Affairs -J. S.Courtney -Pratt, Bell Telephone Labor-atories, Holmdel, N.J.; Vice -Presidentfor Television Affairs -Richard S. O'-Brien, CBS Television, New York,N.Y.; Treasurer -Saul Jeffee, Movie -lab, Inc., New York, N.Y.

Elected to the Board of Governorswere: (Representing the Eastern Re-gion) K. Blair Benson, CBS Television,New York, N.Y.; John J. Kowalak,Movielab, Inc., New York, N.Y.;Henry M. Kozanowski, Radio Corp. ofAmerica, Camden, N.J.; Allan L. Wil-liams, Eastman Kodak Co., Rochester,N.Y.; (Representing the Central Re-gion) Jack Behrend, Behrend's, Inc.,Chicago, Ill.; (Representing the West-ern Region) Jack P. Hall, DeLuxe Lab-oratories, Inc., Hollywood, Calif.; Ed-ward H. Reichard, Consolidated FilmIndustries, Hollywood, Calif.

Other Society officers and boardmembers continue in office through1968.

PERSONALITIES

Two new appointments have beenmade at Broadcast Electronics, Inc.Donald R. Smith, the company's busi-ness manager since 1962, has beenelected vice-president, administrationby the Board of Directors. Prior tojoining Broadcast Electronics, Mr.Smith, a graduate of the University ofFlorida, was station manager ofWMBR, Jacksonville, Fla. and hadpreviously served in various capaci-ties in radio and television stations inFlorida, New York, and Arizona.

The new production -engineeringmanager is Clifford D. Ratliff, who wasformerly chief engineer of MagneticHeads, Inc. Mr. Ratliff has a 15 -yearbackground in electronic engineering,with emphasis on the design of equip-ment employing magnetic tape heads.

'42,


Three appointments have been an-nounced by Philips Broadcast Equip-ment Corp. Thomas G. Kenney hasbeen promoted to manager of pur-chasing. Prior to his association withPhilips, Mr. Kenney was withCeramics International Corp.

Charles E. Irvin has been appointedapplications engineer. Before joiningPhilips, Mr. Irvin held positions withEquitable Life Assurance Society ofthe United States, CBS, RCA, andDynasciences Corp.

Herbert M. Holzberg has beennamed northeast regional sales mana-ger. Prior to joining Philips, he waswith Ampex Corp.

Memorex Corp. has made five ap-pointments. Robert L. Herhusky hasbeen named product manager, instru-mentation tape. Until recently he waswith Dalmo Victor, Inc. John B.Mandle has been appointed directorof quality control. Mr. Mandle hasbeen associated with Memorex for twoyears as manager of product testlaboratory; he was previously withAmpex Corp. William Patsuris hasbeen appointed northwest regionalsales manager. He has been associatedwith Memorex for four years as asales engineer; previously, he was as-sociated with Standard Supply Co.John C. Wiegers has been made south-west regional sales manager. He hasbeen associated with Memorex forover five years, and previously wasassociated with Civil Air TransportCo. John R. Studer has been namedsales engineer, serving accounts froma newly opened branch office in Cleve-land. Prior to joining Memorex, hewas with Burroughs Corp.

TRANSACTIONS

Cable systems in McGehee, Der-mott, and Lake Village, Ark. havebeen purchased by Jim Davidson fromPhilip Farr, Jr.

The assets of radio station WGLB,licensed to Port Washington, Wis. andoperating on the frequency of 1560kHz with 250 watts, have been sold,subject to FCC approval, to RayFriedman and Tom Davis. The pur-chasers also own KLEE, Ottumwa,Iowa. The price was $90,000. The sell-ers are Mrs. Lucy Jeffers and HarveyKitz.

Subject to the approval of the FCC,the assets of radio station KCHY,1590 kHz, 1000 watts, owned byCharles Stone, have been sold toGeorge McCarthy, Robert Chevalier,and Ron Overlander for $50,000.KCHY is located in Cheyenne, Wyo.A

Tape-Athon looks atthe human factor instation automation

In the final analysis, all that's required to start a Tape-Athon Model 5000ALtorratic Broadcasting System operating is a finger-to push the "ON"buttor. But, we realize the user must also get involved prior to start-up andhave, therefore, designed the 5000 with his (or her) comfort in mind.

Programming usually a complex endeavor, has been reduced to amenial task of simply setting a switch bank to correspond with the programformat. Reel changing has been made foolproof by Tape-Athon's exclusive one -hand reel lock and quick threading system. Timing for daily or weekly opera-tion is set by merely punching a timer clock, which will start and stop thesystem automatically - so now you don't even need the finger any more.

A NEW BROCHURE PROVIDING DETAILS AND SPECIFICATIONS ON THE5000 IS AVAILABLE ON REQUEST.

TOP lifitnitCircle Item 34 on Tech Data Card

523 S. Hindry, Inglewood, Calif. 90307 213-678-5445

February, 1968 53

SPOTMASTERSolid -State Portable

REMOTEAMPLIFIER

The RA-4CA is a lightweight, four -channelportable mixer amplifier specifically de-signed for remote broadcast or auxiliarystudio use. It is completely self-containedand operates from either AC or batteries(switching automatically to battery opera-tion if AC power fails); runs as long as200 hours on low-cost "D" cells. It offersfour microphone channels with mastergain and P.A. feed, all controlled from thefront panel. Lightweight construction (just11 pounds with batteries), a convenientcarrying handle and a snap -on front covermean the RA-4CA can be easily set up tooperate anywhere. For further information,please write or call today:

BROADCAST ELECTRONICS, INC.8810 Brookville Road

Silver Spring, Maryland 20910Area Code 301 588-4983

WILKINSON 4N1Portable Solid -State

1. FIELD INTENSITY METER2. NULL DETECTOR3. STANDARD SIGNAL GENERATOR4. AM MONITOR RECEIVER

SUPERIOR BECAUSE THE 4 N 1

Measures field intensity with superioraccuracy and reduces measurement time. Requires only a bridge for easy RF imped-ance measurements. Powered by recharge-able batteries and self -lighted for nighttimemeasurements Easier to carry and operate

FOR COMPLETE DETAILS WRITE:

ELECTRONICS, INC.1931 MacDADE BLVD. WOODLYN, PA. 19094

TELEPHONE (215) 874-5236874-5237

NEW PRODUCTS=II I= INN NIM ME

For further information about any item, circ.e the associated number on the Tech Data Card.

Zoom Lens1431

This new 11:1 zoom lens for colorand black -and -white vidicon systemsfeatures 14 -mm to 145 -mm depth andan f/2.2 aperture. The 3M Co. Wol-lensak TV Raptar 11:1 zoom lens isdesigned for maximum flexibility inoutdoor and studio operations, and tooffer extended zoom range, close-upfocusing (down to three feet with close-up adapting accessories), wide-anglefield for close -range shooting, and wideaperture for improved picture bright-ness under limited lighting conditions.The seven-inch lens is available in bothmotorized and manual configurations.

Tape Splicer144)

The VTR tape splicer is designed tosplice mechanically 2 -inch video tape.The selling price is $1250, and thesplicer can be purchased directly fromBirns & Sawyer Cine Equipment Co.,Inc. or through Ampex or RCA.

Microwave System1451

A hot -standby television microwaveradio system with automatic trans-mitter switching is available from theRaytheon Co. The equipment, desig-nated the Dual Link 2A, is a second -generation addition to the company'sexisting KTR microwave systems. It

transmits monochrome or color TVwith program audio at a minimumoutput power of 1 watt over a fre-quency range of 5.9 to 8.5 GHz or10.7 to 13.25 GHz. The system is allsolid state except for the transmitterklystron, and is intended to operateover a temperature range of - 22 to+131 degrees Fahrenheit. The equip-ment is designed to provide up tofour high-fidelity audio program chan-nels; to exceed all applicable NTSCcolor standards, FCC Rules and Reg-ulations, Bell System practices, andEIA standards; to have no crosstalkbetween main and standby channels;and to allow replacement of equip-ment without service interruption.

Loudness Controller1461

The availability of the new Model710 loudness controller as part of itsstandard audio product line has beenannounced by CBS Laboratories. Theloudness controller analyzes audio ma-terial for such factors as frequencycontent, combinations of complex sig-nals, peak signal factor, and other re-lated phenomena. The results arecompared against human hearing -re-sponse standards to determine if thesignal will sound louder than the sur-rounding program material to thelistener. If the signal is louder, the in-strument acts automatically to reducethe overall gain to maintain the signalwithin acceptable levels.

The Model 710 automatic loudnesscontroller is priced at $825.

Tape Threader1471

A device to facilitate threading reel-to-reel recorders is a product of theTurnex Co. Called Tape-lt-Easy, the

54 Circle Item 25 on Tech Data Card BROADCAST ENGINEERING

nonmetallic threader is constructed toprevent tape from slipping out of thetake-up reel, once it has been insertedin the slot found in standard reels. Itdoes this by pressing the tape againstthe side of the hole into which the tapeend is threaded.

The device consists of four flexiblevanes in a configuration which, com-bined with the elasticity of the softrubber material, is intended to permitconstant pressure against the sides ofthe hole. The purpose of this design isto provide these characteristics: Whilethe threader is strong enough to holdthe tape firmly for instant start of thetransport, the pressure of the flexiblevane will not damage the tape. Shouldthe threader be left in a reel which isbeing unwound, the tape slips outwhen the end is reached. The threadermay be withdrawn after one to twoturns, or it may be left in the reel,since its weight does not upset thebalance.

Tape -It -Easy is sold in a two -reelpackage which contains two of the tapethreaders and two plastic holderswhich may be mounted on or near therecorder. The price is $2.00.

Stereo Converterfor Microwave

(481

A solid-state FM stereo subcarrierconverter has been developed by theCatel Co. for use in microwave relayservice. The Model FMR-2500 offersa choice of subcarrier frequenciesfrom 5.8 MHz to 8.0 MHz for thetransmitter link, and converts back to88-108 MHz at the receiving end.Specifications include an output levelof + 35 dBmv and 50 -dB rejection ofspurious signals. Price of the con-verter is $450.

New Transmitter(491

The Model FM-1KA broadcasttransmitter is powered by a 4CX1000Kpower tetrode which requires less than10 watts of RF drive. The tube incor-porates a solid screen ring which isconnected directly to ground; this ar-rangement is to provide isolation be-tween input and output circuits andeliminate the need for neutralization.Because of the high gain of the 4CX-1000K, the transmitter has no inter -

4 -TUBE PERFORMANCE

3 -TUBE SIMPLICITY

Only new Packard BellColor Camera for film chains combines all

these high-performance featuresin one economical package

Complete matched system-camera plus optical multiplexerpermits wide projector flexibility.

Full EIAINTSC compatibilityobtained with optional plug-inEIA sync modules and encoder.

Unmatrixed monochromaticsignal for maximum definition andcontrast.

Combmation of precision fixedoptics and 3-vidicon simplicityprovides 4 -channel standardsof resolution, contrast and ease ofregistration.

Superior sensitivity -150 foot -lamberts high light -reflectance.

Write today for full informationand prices. c86

Packard Bell IlEg

Lawrence & Arnold Drive, Newbury Perk, Calif. 91320 Tel: (805) 498-6601

February, 1968


55

INSTANT REPLAY

A

Idealinstantplaybacksat low costwith thecae Model 221MechanicalInstantPlaybackAdapter

SATISFIES THE MOSTDEMANDING

VIDEO ENGINEER

Easily installedIntegrates with normal VTRoperation. Levelling feet forprecise tracking.Fast, simple loadingTakes only 5 minutes,including splicing.Efficient tape storageAccommodates 18 to39 -second playbacks.AdjustableSliding pulley adjusts tensionfor odd lengths of tape.Strong and lightweightHeavy gauge aluminum con-struction for easy portability.

Let us solve your instantplayback problems. ContactONEIDA ELECTRONICS INC.

805 Court Street,UTICA, New York.

cae INDUSTRIES LTD.Electronics Division (Western),

387 Sutherland Avenue,WINNIPEG 4, Manitoba.

cae

mediate power amplifier. The power -amplifier filament supply is regulatedfor improved tube life.

Specified line -power requirement is2.3 kw. The transmitter is designed forremote control (including plate tun-ing), and it measures 76" x 28" x 28".

Available from stock, the AmericanElectronics Laboratories, Inc. ModelFM-1KA is priced at $5990.

Dual -Channel Audio Console(50)

A self-contained dual -channel audioconsole designed for use in broadcastand recording applications is availablefrom McCurdy Radio Industries, Inc.The all -solid-state console (Model SS -4360) is comprised of ten mixing chan-nels; two program channels; control -room and studio monitors with mutingand warning -light relays; a cue andtalkback system; and a built-in powersupply with individual regulated out-puts for program amplifiers, cue am-plifiers, and monitor amplifiers.

The mixing channels can accommo-date up to 34 program sources, andany input mixing channel may be usedfor high- or low-level operation byusing the proper plug-in module. Mix-er positions 1 through 9 have 3 -posi-tion input selector switches. Mixerposition 10 has a 5 -position selector inaddition to the 3 -position key for re-mote and network inputs.

The console accommodates twoplug-in 10 -watt program -monitor am-plifiers in addition to the cue amplifier.The control -room monitor is suppliedas an integral part of the console. Thestudio monitor amplifier is available asan option.

Program levels are continuouslymonitored by two VU meters. The B -

channel meter may be selected to readfour external program levels. In addi-tion, jacks are provided for cue andmonitor headsets.

The cue -intercom system providesfor use of an internal, separate talk -

back microphone and cue speaker foroptimum intelligibility and simplifiedswitching.

1 -kw UHF Translator(51)

A new UHF television translator,developed by Emcee Broadcast Prod-ucts, a division of Electronics, Mis-siles & Communications, Inc., retrans-mits signals at 1000 watts peak visualpower, 100 watts average auralpower. The translator is self-contained

BROADCAST

EQUIPMENT

ALL SOLID STATE

AURAL

STLModel PCL-303

+ 8 watts at 950 MHz

+ True direct FM+ Silicon semiconductors

+ Sensitive receiver withratio detector

+ For all STL bands

MOSELEYASSOCIATES, INC.

135 NOGAL DRIVESANTA BARBARA, CALIFORNIA

(805) 967-0424Circle Item 28 on Tech Data Card

You can't buy a better tapeat any price!

And-you makemore, much more,with Irish!

Complete line of cassettes,4 and 8 track cartridgetape, reel-to-reel tape and//2 and 1 inch video tapes.Write for complete details.

IRISH TAPE458 Broadway, N.Y. 10013


MOVING?Don't lose touch . . .

RECEIVE BE AS USUAL

(INCLUDE OLD AND NEW ADDRESS)

BROADCAST ENGINEERINGCIRCULATION DEPT.4300 W. 62nd St.,

Indianapolis, Ind. 46206



and includes control circuitry forautomatic, unattended operation.When used with an antenna providinga gain of 10, it can be used to pro-vide 10 kw ERP.

The new translator design incor-porates transistorized circuitrythroughout, with the exception of themixer and final amplifier. The manu-facturer is currently marketing two1 -kw translator models and a 1 -kwadd-on amplifier to increase the poweroutput of existing translator stations.

Kilowatt RF Calorimeter152)

A new RF calorimeter designed tomeasure power in 50 -ohm coaxial sys-tems up to 1000 watts with 3% typicalaccuracy is available in five versionswith "N," "C," or 17/8 -inch EIAflanged connectors. Power is deter-mined from input -to -output tempera-ture differential at a constant flow rate.

These Bird Electronic Corp. Terma-line RF calorimeters are self -checkingat DC or 60 Hz AC, resulting in11/2 % stated accuracy. The instru-ments are portable to the point ofmeasurement and are built to be unaf-fected by ambient conditions. Becauseof low thermal inertia of the RF loads,response time to stability is short.Specifications include: VSWR, 1.1 maxDC -1000 MHz, 1.25 max to 3500MHz; price, Model 6020, $895.

The Model 398 flutter is an all -solid-state instrument intended to make pre -

Flutter Meter153)

cision rms flutter measurements on anymagnetic tape recorder. The internaloscillator develops a 3 -kHz referencetone which is recorded on tape. Speedvariations (flutter) in the recorder drivemechanism are then sensed duringplayback by a pulse -averaging discrim-inator and displayed on a dual -rangepanel meter. A precalibrated scopeoutput permits viewing the flutterwaveform directly.

Specifications of this Video Re-search Corp. instrument include: refer-ence frequency, 3 kHz; referenceoutput level, 2 volts rms; referenceoutput impedance, 75 ohms; discrimi-nator input -level range, .15 to 15 voltsrms; discriminator input impedance,5000 ohms; meter ranges, 0.3% and1.0% rms full scale; scope output, 2volts p -p equal full scale. Price of theModel 398 is $485.

A color broadcast camera designedfor one-man coverage of news andsports events has been developed byAmpex Corp. at the request of theAmerican Broadcasting Co. The ModelBC -100 may be operated over a minia-ture cable up to 2000 feet long, or itmay also be operated by a battery -powered unit via a built-in microwavelink.

The Plumbicon camera head weighsless than 20 pounds and is mounted ona shoulder harness to permit hand-heldoperation. Associated camera electron-ics are contained in an attache -typecarrying case on the cameraman'sback. Equipped for microwave opera -

PA Pt TAELECTRONIC CORPORATION

5851 Florin Perkins RoadSacramento, Calif. 95828 (916) 383-5353

NOWA DEMAGNETIZERWITH AN EXTRA -LONG WAND

MAGNETISM CAN RUIN TAPES!

The original sound quality of alltapes can only be maintained byusing a demagnetizer. The EXTRA -LONG wand of the DM -200 letsyou reach the most inaccessibletape head areas of any machine.Takes just a few minutes and willeliminate distortion and back-ground noise caused by magnetism.

PRICE: $6.95FOB Sacramento, Calif.

PDrtable Color154)

tion, the pack weighs 30 pounds; whenequipped for cable use, it weighs 15pounds.

The color picture from the camerais relayed to a base station, which con-sists of the processing electronics, anencoder, picture and waveform moni-tors, and sync generator. From thebase station the picture is fed to thetelevision station for broadcasting.

The camera is 18-5/8 inches longwith its 6:1 zoom lens, 13 -inches highand 71/2 -inches wide with electronicviewfinder. The back panel is 23" x133/4" x 6". At a light level of 150foot candles, a signal-to-noise ratio of42 dB and a bandwidth of 4 MHz arespecified for the camera.

Camera

OperatingRemote Control?Be safe and sure!

witht ALL ZOL 0]-cAM RF AMPLIFIERFROM WILKINSON!

Features of the Model TRF 1A: VERY LOW DISTORTION AND

CARRIER SHIFT BROAD GAIN CHARACTERISTICS EXTREME STABILITY EXCELLENT SELECTIVITY ULTRA LINEARITY

PRICE: $395For complete details write:

rmELECTRONICS, INC.

1987 MacDADE BLVD. WOODLYN. PA. 19094 TELEPHONE (215) 874-5236 874-5237


February, 1968Circle Item 29 on Tech Data Card 57

"Flazkinas

NEW!!

UD-865

U ni-DirectionalDynamicMicrophone

Designed for use at broadcastingstations, music stages and suit-able for hi-fi recording.Eij +1o_.,"`..73 0

a) -10inC -2*a,. -30`cci

I 10

1

tk Sk 10k 20ko

SPECIFICATIONS:"Cartridge: DM -33Frequency Response

50-15,000 cps ± 5dBI m pedance: 600n ,50kci"Sensitivity:

-72dB/-53dB t 3d8Dimensions:

341 x 160m/m

For further information please write to

PRIMO COMPANY LTD.Head Office: 25 I. 6 chome. More. Mitakashi, Tokyo. Japan Tel 0422-43-3121-6

Cable "Primo Musashino Melaka" Telex 2822.326 PRIMO MUSChicago Illinois Office: A P T No 204, 530 W. Surf. St. Chicago Illinois 60657,

U S.A. Tel. 312.472-61421 Telex* 25.4225 PRIMO MUS CGOILLUSA

Item 31 on Tech Data Card

COOPERATE

WITH THE

ZIP CODE PROGRAM

OF THE

POST OFFICE DEPARTMENT

USE ZIP CODE NUMBERS

IN ALL ADDRESSES

ENGINEERS' TECH DATA

ANTENNAS, TOWERS &TRANSMISSION LINES

55. DEEHI-Twelve-page catalog concerns towers and masts forCitizens -band and similar applications.

56. JAMPRO-Catalog contains specifications on new CP seriescircularly polarized antennas for FM broadcasting.

AUDIO EQUIPMENT

57. ATLAS SOUND-Form PP -1840 is catalog sheet for microphonestands, booms, and accessories.

58. CROWN-SA30-30 two -channel, solid-state audio power am-plifier is subject of information sheet.

59. FAIRCHILD RECORDING EQUIPT.-One-page Technical Bul-letin presents FICM integrated -module strip for console de-velopment.

60. GATES-Brochures have as their subjects professional turn-tables and accessories, and Model M-6600 all-purpose andremote amplifier.

61. RYDER MAGNETIC SALES - Information about Sela 2880audio mixer for use with Nagra recorders is offered.

62. SHURE-Eight-page Professional Products catalog lists micro-phones, circuitry, cartridges, tone arms, and microphone ac-cessories.

63. SWITCHCRAFT-New Product Bulletin No. 170 gives descrip-tions and prices of seven new audio accessories, includingjack, adapter, and cables.

64. UNIVERSITY - 28 -page Commercial Sound Product Cataloglists speakers, horns, drivers, microphones, and sound col-umns; includes sound -system design chart, formulas, and tech-nical data.

COMPONENTS & MATERIALS

65. ELCO-Catalogs offered are: Printed -Circuit Connector Guide(64 pages), MIL -C-26482 Connector Catalog (20 pages), Vari-plate Connector Catalog (24 pages), Tube and Transistor Sock-et Catalog (14 pages), and Varicon Rack and Panel ConnectorCatalog (24 pages).

66. IERC - Eight -page, illustrated Short -Form Catalog includesspecifications and prices for line of semiconductor heat dissi-pators and tube shields.

67. TROMPETER-Catalogs M-4 and T-6, listing coax, twinax, andtriax patching and switching products, are offered.

LIGHTING EQUIPMENT

68. BERKEY COLORTRAN-Issue No. 4 of ColorTran News fea-tures application stories of interest in the motion -picture andtelevision industries.

69. MOLE-RICHARDSON-Supplement No. 1 to Catalog K illus-trates seven new quartz lighting fixtures and several otherproducts. Twenty -page price list for the company's productsalso is available.

MICROWAVE & STL EQUIPMENT

70. MICRO-LINK/VARIAN - Descriptive specification sheet isabout TVL Series TV -relay equipment.

MISCELLANEOUS

71. DENSON-Sheets include descriptions of numerous items ofnew and used equipment.

72. TEXWIPE - Folder has as its subject the Texwipe PrecisionCleaning Kit for magnetic tape equipment.

POWER DEVICES

73. CLARE-ELECTROSEAL-Bulletin 1352 is about Electro-Pac "A"standby power supply; Bulletin 1351 is about Electro-Pac "B"sine -wave inverter; and Bulletin 1371 is about Electro-Pac"C" all -solid-state AC voltage regulator.

74. ONAN - Two -page specification sheet has illustrations and


data for line of electric generating plants designed for mobileapplications.

RECORDING & PLAYBACK EQUIPMENT75. AMPEX-Literature available includes Bulletin V138 about

VR-1200B high -band color video tape recorder, Bulletin V131about VR-2000B high -band color recorder, and Bulletin T160about 142 Series video tape for helical -scan machines.

76. ELECTRONIC ENG'G-Eight-page booklet contains informa-tion about On Time editing and control equipment for TV taperecorders.

77. JOA-Prices and data are given for new tape cartridges andfor cartridge -reconditioning service.

78. METROTECH-500A Series recorders, reproducers, and slow -speed loggers are presented in two -page circular.

79. TELEX - Descriptions of Viking Studio 96 and MagnecordModels 1021 and 1022 tape recording and reproducing equip-ment are given in literature.

REFERENCE MATERIAL & SCHOOLS80. CLEVELAND INSTITUTE OF ELECTRONICS-Pocket-size plas-

tic "Electronics Data Guide" includes formulas and tablesfor: frequency vs. wavelength, dB, length of antennas, andcolor code.

TELEVISION EQUIPMENT81. ALBION-Model 520 servo -controlled pan and tilt system is

shown in four -page, two-color brochure.82. ALMA-Publication gives information about AS 6500 Custom

Series video switching systems.83. CANOGA ELECTRONICS - Series VT -500 long -haul video

transmission and terminal equipment, and Series 1270 minia-ture TV camera control are subjects of literature offer.

84. CANON USA-Literature having to do with 16 -mm lenses formovie and TV use is available.

85. CLEVELAND ELECTRONICS-A 52 -page quick -reference step-down die -cut catalog gives information on vidicon, Plumbi-con, and image -orthicon deflection components.

86. COHU-Eight-page booklet, No. 8-91, is titled "The ABC's ofETV."

87. COLORADO VIDEO-Short Form 100 lists bar graph genera-tors, video analyzers, slow -scan TV, scan converters, labora-tory cameras, sync generators, and video -to -digital conveners.

88. DYNAIR-Eight-page, illustrated short -form catalog lists lineof professional television equipment.

89. KALART-Literature is offered for Model STV-TB 16 -mm TVprojector, "Moviematic" and "Duolite" 16 -mm projectors, andTele-Beam large -screen TV projector.

90. TELEMATION - Porta-Sync, all -digital miniature broadcastsynchronizing generator, is described in catalog brochure.

91. TELEMET-Information sheets are for Model 3252 -Al differen-tial phase and gain corrector, and Model 3701 -Al differentialphase and gain test receiver.

92. VITAL-Model VIX-108, new integrated -circuit vertical inter-val switching system, is sub;ect of literature.

TEST & MEASURING EQUIPMENT93. BALL BROS. RESEARCH-Specifications and information about

Mark 21-RM video waveform monitor are given in catalogsheet.

94. B & K-Bulletins are available for the following instruments:Model 2409 AC voltmeter/amplifier; Model 4240 simulatedvoice mechanism, for testing telephone transmitters and hand-sets; Model 2410 AF voltmeter/amplifier; Model 2417 rms volt-meter; Model 2006 heterodyne voltmeter; and Model 3350/51electroacoustic transmission measuring system, for tests ontelephone handsets.

95. DELTA-Information sheet has as its subject the Model RG-1receiver/generator for use with impedance bridges in an-tenna -system measurements.

96. EICO-1968 short -form catalog, including test equipment inkit or wired form, is offered.

97. METRON-Information about Model 506B-1 amplitude modula-tion monitor is contained in specification sheet.

98. TEKTRONIX-Description and specifications are available forType 520/R520 NTSC vectorscope, designed to measure lumi-nance, hue, and saturation of NTSC color TV signal.

New...FADER ARMNow availablefor usewith AEMLap -dissolveAmplifiers

NOW. the smooth, velvety transition func-tion associated with AEM's Lap -Dissolve amplifierscan be remotely obtained by means of AEM's new,compact fader arm assembly.

Easily paralleled into existing LDA-1 or LDA-2 ampli-fiers, the assembly can be readily mounted into a con-trol console with minimum interconnections. Teflonslides assure ease of movement while built-in limitswitches, at each end of travel, can control externalfunctions. Although designed for operation withAEM's LDA-series amplifiers, the fader arm controlcan also be adapted for use with other similar equip-ment. Panel mounting dimensions are 25/8" x 75/8",and weight is 11/2 pounds. Prices: $65 if purchasedfor use with LDA-series amplifier; $95 if purchasedalone. For further information, please contact:

APPLIED ELECTROMECHANICS, INC.2350 Duke Street, Alexandria, Virginia 22314PHONE: (703) 548-2166

February, 1968


59

The soundest sound in audiois the new sound of Gates

What FM transmitterpower do you need?

Gates has the most complete line ofFM transmitters in the industry. From10 watts to 40,000 watts. All withthe solid state "DCFM" 10 -watt FMexciter. Tell us the power you needand ask for data on our FM antennas.Write or phone (217) 222-8202 today.

GATESHARRIS

INTERTYPE

ON

GATES RADIO COMPANYQUINCY, ILLINOIS 62301, U.S.A.A subsidiary of Harris-Intertype Corporation


SPOTMASTERThe all solid state AD1A

AUDIODISTRIBUTIONAMPLIFIER

INN-

41 * u *

Meet the AD1A, a solid state audio dis-tribution amplifier specifically designed forAM, FM and TV broadcast stations andrecording studios. The AD1A distributesaudio signals via five separate outputchannels (up to 25 with the addition ofAD1A-X extenders), and incorporates afront -panel VU meter and monitor jack topermit visual and aural monitoring of theincoming signal at the output of the lineamplifier. Response is essentially flat from40 to 20,000 Hz, with low distortion andnoise, 50 db channel isolation and 12 dbpeak factor. For further information, writeor call today:

BROADCAST ELECTRONICS, INC.8810 Brookville Road

Silver Spring, Maryland 20910Area Code 301 588-4983

Advertisers' Index1. MIN MN Mill VIII

Allen Avionics, Inc. 52

Andrew Corp. 45

Applied Electro Mechanics, Inc. 59

CAE Industries, Ltd. 56

CBS Laboratories,Div. of CBS, Inc. 5

Cleveland Institute of Electronics 33

Cohu Electronics, Inc. 3

Collins Radio Co. 29

Conrac Div., Conrac Corp. 46, 47

Electro-Voice, Inc. 15, 36, 37

Fairchild RecordingEquipment Co. 6

Gates Radio Co. 11, 60

Industrial Electric Reels, Inc. 42

International Nuclear Corp. Cover 3

ITT Federal Electric Corp. 8

Jampro Antenna Co. 23

Kappa Networks, Inc. 49

Lipsner-Smith Corp. 52

Microwave Associates 32

Morhan National Sales 56

Moseley Associates, Inc. 56

Packard Bell,Space & Systems Div. 55

Phelps Dodge

Electronic Products Corp. 21

Philips BroadcastEquipment Corp. 16, 17

Primo Co., Ltd.

Riker Video Industries, Inc.

58

Cover 2

Round Hill Associates, Inc. 25

Shure Brothers, Inc. 41

Sparta Electronic Corp. 57

Spotmaster (BroadcastElectronics, Inc.) 48, 54, 60

Stanton Magnetics 10

Tape-Athon 53

TeleMation, Inc. 50, 51

Teie-Measurements, Inc. 34

Telemet Co. Cover 4

Vital Industries 9

Ward Electronic Industries,

Wilkinson Electronics, Inc.

Inc. 7

54, 57,60

Replace

MercuryVaporTubes

Directlywith

it

EVA IP NIt6S R -6

Silicon RectifierStacks!Because...O Only non -encapsulated WILKIN-

SON Silicon Rectifiers can be re-paired in seconds with low-costreplacement diodes!

O Exclusive "GO, NO GO" indicatorautomatically warns when the re-verse leakage of any diode is inexcess of 50 microamps.

D Only WILKINSON Silicon Rectifi-ers are available in a completetube replacement range of from866 to 857B.

O WILKINSON Silicon Rectifiersfunction in ambient temperaturesof from - 85 F to +158 F.

No more filament heat and conse-quent filament burnout ... lowerpower cost and reduced hum, too.

No warm up time is necessary ...instantaneous operation!

O Just plug in WILKINSON SiliconRectifiers... no re -wiring isnecessary.

O Only WILKINSON Silicon Rectifi-ers are fully guaranteed and havea safety margin well in excess oftube rating.

For complete details write today to:

WILKINSONELECTRONICS, INC.

1937 MACDADE BLVD. WOODLYN, PA. 19094TELEPHONE 12151 874-5236 874-5237

60Circle Item 34 on Tech Data Card


Professional ServicesMINI SIM MI MI

VIR JAMESCONSULTING RADIO ENGINEERSApplications and Field Engineering

345 Colorado Blvd.Phone: (Area Code 303) 333-5562

DENVER, COLORADO 80206Member AFCCE

TWX 910-931-0514

JAMES C. McNARY

Consulting EngineerNational Press Bldg.

Washington 4, D. C.Telephone District 7-121 i

Member AFCCE

CAMBRIDGE CRYSTALSPRECISION FREQUENCY

MEASURING SERVICESPECIALISTS FOR AM -FM -TV

445 Concord Ave. Phone 876-2810Cambridge, Mass. 02138

AMPEX HEAD ASSEMBLY RECONDI-TIONING SERVICE for all Ampex pro-fessional model recorders. This profes-sional service features precision relap-ping of all heads for maximum bead life.Your assembly is thoroughly cleaned andguides are replaced as required. Price in-cludes optical and electrical inspectionand complete testing on Ampex equip-ment in our plant. Full track or halftrack assemblies . . . $35.00. One to twoday service. "Loaner" assemblies avail-able if necessary. LIPPS, INC., 1830Euclid Street, Santa Monica, California90404. (213) EX 3-0449. tf

CRYSTAL AND MONITOR SERVICE - Fre-quency change and repair service for AMmonitors including G.R., RCA, Gates, W.E.,and Doolittle; also H -P 335B FM. AM moni-tors bought and sold. What have you, whatdo you need? New or regrinding of AMcrystals for RCA, Gates, Bliley, W.E., andJ -K oven holders, repairs, etc. Fastest serv-ice, reasonable prices. Over 25 years inthis business. Eidson Electronic Co., Box96, Temple, Texas 76501, Phone 817 773-3901.

2-67-tf

ROSNER TELEVISION

SYSTEMS

ENGINEERS CONTRACTORS120 E. 56 St.New YorkN. Y. 10022

230 Newtown Rd.PlainviewN. Y. 11803

VIDEO TAPE RECORDERAUDIO HEAD ASSEMBLY SERVICE

Precision relapping of all heads and sup-porting posts, including cleaning andtesting. Ampex head assembly with "cue"tracks, $75.00 complete. RCA units alsorelapped. One to two day service. LIPPS,INC., 1630 Euclid St., Santa Monica, Calif.90404. (913) EX 3-0449. tf

JOHN H. MULLANEYand ASSOCIATES

Suite 71,1150 Connecticut Ave., N.W.

Washington, D. C. 20036Phone 202-223-1180

Member AFCCE

CANADALEONARD H. MAILEB.Sc., M.E.I.C., P.ENG

CONSULTING STRUCTURAL ENGINEERCOMMUNICATIONS TOWERS

TELEPHONE BOX 512, STATION Q489.6587 TORONTO 7, ONTARIO

FRANK A. ZOELLERTelevision Systems Consultant

20 yrs. experience in TV and ETV- All phases. Box 366, San Carlos,Calif. 94070. Pr. (415) 593-1751

Classified

Advertising rates in the ClassifiedSection are fifteen cents per word.Minimum charge is $2.00. Blind boxnumber is 50 cents extra.

Equipment for Sale

SPOTMASTER cartridge equipment andaccessories, Crow tape recorders, QRK,versal Audio Products, Pultec, NorelcoRek-O-Kut, Russco (turntables andpreamplifiers) Gray and Euphonies tone -arms, Metron modulation monitors,Universal Audio Products, Pultec, Norel-co-AKG microphones, Fidelipac andAudiopak cartridges. Writes for specialmoney saving offers. Audiovox, Box7067-55, Miami, Florida 33155. 11-67-tf

CO -AXIAL CABLE Hellas, Styroflex, Spiro -line, etc. Also rigid and RG types in stock.New material. Write for list. Sierra -WesternElectric Co., Willow and 24th Streets, Oak-land, Calif. Phone 416 832-8527 5-56-tf

Television / Radio / communications gear ofany type available. From a tower to atube. Microwave, transmitters, cameras,studio equipment, mikes, etc. Advise yourneeds-offers. Electrofind Co., 440 ColumbusAve., NYC. 212 -EN -25680. 8-84 tf

"AUDIO EQUIPMENT - Whatever yourneeds, check ue first. New and used. Am-pex, Altec, AKG, EV, Fairchild, Neumann,Langevin, Rek-O-Kut, Uher, Viking. Sendfor equipment list." Audio Distributors,Inc., 2342 S. Division Ave., Grand Rapids,Michigan 49507. 6-66-tf

CARTRIDGE TAPE EQUIPMENT

Completely reconditioned and guaranteed.Spotmaster Model 500 Record/Playbacks,$350.00. Model 505 Playbacks $250.00. 30 -

day money -back guarantee on all equip-ment.

BROADCAST PRODUCTS COMPANY18804 Woodway Drive, Derwood, Maryland,

20855(301) 926-4600 3-87-12t

Everything in used broadcast equipment.Write for complete listings. BroadcastEquipment and Supply Co., Box 3141, Bris-tol, Tennessee. 11-64-tf

Audio Equipment bought, sold, traded.Ampex, Fairchild, Crown, McIntosh, VikingF. T. C. Brewer Company, Town & CountryPlaza, Pensacola, Florida. 3-64-tf

BROADCAST EQUIPMENT REBUILDERS ...your headquarters for tape cartridge recon-ditioning, all work fully guaranteed! WriteQuin Morrison about your used equipmentneeds. New Address: Box 276, Hickory, N.C.28601. 11-67-tf

Coils, Contactors, Switches, Complete ATUsystems. Top Quality, Lowest Prices, FastDelivery, No Duty. Write for catalogue:Geleco Electronics Ltd., 2 Thorncliffe Pk.Dr., Toronto 17, Ont. 416-421-5631. 11-67-12t

TOWERS, lights and accessories AM FM com-munication, CATV, sales, erection and completeservice, world wide. Write Dixie SteeplejackCompany, 2832 Riverview Blvd. West, Braden-ton, Florida. tf

RCA TT -5A, CHANNEL 5 Transmitter withside -band filter, WM-12, WM-13, Visual Modu-lation Converters and Power Supply. No con-trol console. R. E. Oldfield, Southern ColoradoState College, Pueblo, Colorado 81005. 1-68-2t

FOR SALE: Two Gates CB -11 16" turntablesin cases, complete with Rek-o-cut 160 arms,GE VR-11 pickup, Gates pre -amp & DavenPot w/cue. 600 ohms out, connect and go!$200.00. Fairchild disc recorder with head,no amplifier. $125.00. Gates dynomote remoteamplifier, 4 channel, $200. Cleaning house.WFOX Radio, Milwaukee, Wis. 53/02 (ChiefEngineer). 2-68-1t

Equipment Wanted

We need used 250, 500, 5K & 10K \VattsAM Transmitters. No Junk. GuaranteeRadio Supply Corp., 1314 Iturbide St.,Laredo, Texas 78040. 3-66-tf

SPOTMASTERS WANTED-Model 500 Re-cord/Playbacks and Model 505 Playbacks.Send full details to: BROADCAST PROD-UCTS COMPANY, 18804 Woodway Drive,Derwood, Maryland 20855 (301) 926-4600.

10-67-6t

WANTED-Used 3 to 10 Kilowatt FM Trans-mitter with exciter (stereo if available),modulation monitors, and FM antenna. In-terested in complete station as above orindividual items. Write giving full detailsto Box No. 195. BROADCAST ENGINEERING.

2-68-1t

February, 1968 61`

Employment

IMMEDIATE OPENINGS-Qualify for anyof the following positions: Technicians forRCA Closed Circuit Television equipment,Cameramen, Maintenance men, Video Tapemen, Video Engineers, Sales Engineers. RCARep. 143-08 94th Ave., Jamaica, New York,or (212) 297-7344. 7-67-tf

Electrical Engineers needed immediately forTV/Radio stations, manufacturers, andCATV for all positions. Send well preparedresume to Nationwide Broadcast PersonnelConsultants, 645 North Michigan Avenue,Chicago, Illinois, 60611. We have openingsfor all qualified applicants and the em-ployer pays our fee. 10-67-tf

Immediate opening for Broadcast Engineer.All color station, second class license orbetter required. Send resume to WNYS-TVChannel 9, Syracuse, Inc. P.O. Box 9,

Syracuse, N.Y. 13214. 10-67-tf

Job Headquarters for all Radio and Tele-vision Engineers. Immediate openings existin 9 western states and elsewhere for qual-ified engineer and technical personnel. Allcategories from trainees to experiencedtransmitter maintenance, chief, assistantchief, live color video maintenance andtechnical operations. Send us your com-plete resume now. The AMPS Agency, 3924Wilshire Blvd., Los Angeles, California90005. Telephone DU 8-3116.By Broadcasters-For Broadcasters 11-86-tf

Opportunity for engineer with black -and -whiteTV experience to learn color in a mediumsized market using new Plumbicon camerasand highband VTR's Call Chief Engineer col-lect today - 313-239-6611. 12-67-3t

Wanted: Chief Engineer for medium marketAM/FM station. Northeast U.S. No announc-ing. Market leader. $130/wk. Send resume toBox 190. 12-67-4t

Opportunity to work in all phases of TVtechnical operation with live color -VHF inbeautiful Texas resort city. Box 194. 1-68-2t

WANTED-First Phone licensed engineer towork in South. Must have four to five yearsexperience in TV broadcasting as studio main-tenance engineer. Send resume with salary re-quirements to Box 191. 1-68-3t

WANTED-Experienced CATV technician towork in South. Send resume with salary re-quirements to Box 192. 1-68-3t

Established western manufacturer &

distributor needs SERVICE MANAGER.Must be experienced in:Broadcast Studio Equipment,

Including VTRColor TV Equipment,Supervision of Technical PersonnelLimited travel. Excellent benefits.Salary dependent on qualifications. Sendresume to Box 197. 2-68-2t

BROADCAST SALES ENGINEERExclusive territory for sale of rapidlyexpanding line of broadcast equipmentrequires highly motivated, sales -minded in-dividual with strong technical knowledge ofequipment primarily to AM, FM, and TVstations. Leading company with history ofhigh profit and rapid growth. Salary pluscommission-with full fringe benefits andtravel expenses paid. An equal opportunityemployer. Send resume to Box 196. 2-68-2t

Training

To advance in electronics, knowledge andability are required. Grantham offers cor-respondence and resident instruction, indepth, leading to the degree of Associate inScience in Electronics Engineering. G.I. Billapproved. Credit for previous training andexperience allowed. Free Catalog. Write:Dept. E-2, Grantham School of Electronics,1505 N. Western Ave., Hollywood, California90027. 8-67-tf

Is Your

Blood Pressure

HIGH?Only your doctorcan tell. Now hecan control mostcases with pres-sure -loweringdrugs and newmethods oftreatment.But more re-search is neededto find ways ofpreventing thisleading cause ofheart attack andstroke.Your Heart Funddollars helpmake this re-search possible.

GIVE...so more will live

HEART FUNDContributed by the Publisher


1/4 A

r

rI

/ N

I

Name

Address

Title Company

City State Zip

Mail your entry to International Nuclear Corporation, 608 Norris Avenue, Nashville,Tennessee. Decision of the Judges is final, and duplicate prizes cannot (understandably)be awarded. The winner, if any, will receive the secretarial services of Miss InternationalNuclear for a five day work week.

1 2

3 4

5

7

9

6

8

4; X; )14.44P

10_J

Miss ternationalNuc ar for seven

fu -filled days.Here's a nifty contest. Simple rules. If you can name all the Inter-national Nuclear products pictured above, we'll send you a neat8 x 10 glossy picture of Miss International Nuclear (in a plainbrown wrapper). We'll even send you one for a good try. If youown one or more of each of the International Nuclear productspictured above, we'll send you Miss International Nuclear ... tokeep as your personal secretary for one glorious week. Offergood until March 15, 1968. Order at least one of everything NOW! NUCLEAR CORP.


MAKE YOUR IF NOISE FEEL "REJECTED"with these Clamping Champs by Telemet

1

CLAMPER AMPIIfVER

ORD

DC

CLAMPER AMPLIFIER MODEL 3203 For general use in 75 ohm systems

Feedback type clamp with four outputs Hum rejection 34 dB nominal

Sync addition capabilities for non -composite signals

pOY[A a,2V YAV. fi*D tf4

01111.44

CLAMPER AMPLWIE

AAALARat

TOSit0t0Ide 140D(LITAIC,:,TELENET CO 4101,1MLE

141 cLOW

epr

CLAMPER AMPLIFIER MODEL 3203-C1 Multi -purpose clamper

Switchable inputs 75 ohm unbalanced and 124 ohm balanced 18 dB gain for microwave applications

Ideal for clamping 124 ohm balanced video pairs High frequency compensation on front panel

2

MICROWAVERF..1EIVER

751

BALANCED124 12 VIDEO

PAIR

3203-C1CLAMPER

WAVEFORMMONITOR

BALANCEDVIDEO

TRANSMISSIONSYSTEM

TELEMET COMPANY185 DIXON AVENUE / AMITYVILLE, NEW YORK 11701 / PHONE: (516) 541.3600


Documents

TM Broadcast Engineering - americanradiohistory.com...SAN FRANCISCO OFFICE The Maurice A. Kimball Co., Inc. 580 Market St., Room 400 San Francisco, California 94104 (415) 392-3365