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ISSN 0141-0857
7701410
0850 13
03>
prac ica MARCH 1993 £1.75
FREE INSIDEGREENWELD
32 -PAGE SPRINGCATALOGUE
ANDThe London
Amateur RadioShow Exhibition
Guide
Antenna Workshop - Build An HF Bands Mobile AntennaModifying PMR Equipment - For Amateur Radio useNew Look - HF Bands, VHF and Broadcast Specialist ArticlesValve & Vintage - Looking At Older EquipmentBits & Bytes - The Computer In Your ShackPlus - Competition, Bargain Basement & Lots More!
"BEST COMMUNICATIONSRECEIVER 1992": WRTVH
FFIG1100
YAESUCON.KLAiiCK,La arCL,K0i FliG-100
POWER
-C4. rota
tin AtO.! CLOCK 7,01 Sit SIT DIM
PHONES MELT SCE. VOL
0SSO CWIN AN'.0N FM
loom MKT. 1,71
sc.. se, p.
FAEit."=31
SEE THIS AWARD WINNING RECEIVERAND THE REST OF THE YAESU RANGE INCLUDING
THE SUPERB FT1000, FT990 AND FT890at
Picketts Lock Centre,Stand M,Red HallLONDON
AMATEUR RADIO c,7& COMPUTER
SHOW on[... AMATEUR RADIO
& COMPUTERSHOW
LONDON
Saturday 13th March and Sunday 14th March
YAESUPerformance withoutcompromise
SOUTHAMPTON (0703) 255111Showroom (0703) 2251549SMC HO. & Mail OrderSchool CloseChandlers Ford Industrial EstateEastleigh, Hants SO5 3BYgam-5pm Mon -Fri; Scan-Ipm Sat
CHESTERFIELD (0246) 453340SMC Midlands102 High StreetNew WhittingtonChesterfield9.30can-5.30pmTues-Sat
LEEDS (0532) 350606SMC NorthernNowell Lane Ind. Est.Nowell LaneLeeds LS9 6JEgam-5.30pm Mon -FriScan -1 pm Sat
Sameday despatch
wherever possible Yaesu Distributor Warranty,
12 months parts and labour Carriage charged on all items as indicated
or by quotation Prices and availability subject tochange without prior notice Free Finance' on selected
items, subject to status. Details available on request Up to £1000 instant credit, a quotation in writing is available onrequest, subject to status
BIRMINGHAM 021-327 1497SMC Birmingham504 Alum Rock RoadAlum RcckBirmingham B8 3HXgam-5pm Tues-Fri9arn-4pm Sat
AXMINSTER (0297) 34918Reg Ward & Co. Ltd1 Western ParadeWest StreetAxminsterDevon EXI3 5NYScan-5.20pm Tues-Sat
21 Review- The MaxcomMX -9000Richard Ayley G6AKG tries out an interesting
four -In -one test instrument
24 What A Good Idea!David Porter G40YX, and G3JDK share their Ideas
for a simple power supply and a storage system
26 Antenna WorkshopPeter Dodd G3LDO describes a very practical h.f.
mobile antenna project
30 Bargain BasementBargains galore in the PW reader's 'for sale &
wanted' adverts
32 Converting A 27MHzMultimode TransceiverConverting a CB is not difficult, and P. E. Francis
explains how easy it is
34 Modifying The PyeOlympic P Band TransceiverKen Ginn G8NDL shows you how to get on to
70MHz for a
bargain price!
37-40London Amateur Radio ShowPull -Out GuideCome and meet the PW and SWM teams at the
London Show on Stand Tin The Red Hall on 13
and 14 March 1993.
41 Special Pre -publicationOffer - The Newnes PracticalRF Handbook By Ian HickmanBuy this book at a special pre -publication price
42 A User Guide To934MHzJohn Levesley GOHJL provides a plain man's
guide to this fascinating part of the radiospectrum
46 Bits & Bytes - TheComputer In Your ShackPeter Hunter GOGSZ takes his bi-monthly look
into the world of amateur radio and computers
48 Back To The Future In1901! - The First RepeaterStan Crabtree G3OXC looks back 92 years to the
first known wireless telegraphy repeater
50 Satellite ScenePat Gowen with his monthly views on amateur
radio in orbit
52 Visit Friedrichshafen,Dayton or OrlandoOur annual trips to the world famous radioshows in Dayton and Friedrichshafen have
become a firm favourite with our readers. Now,It's time to think about this Year
StaffEDITORIAL & ADVERTISEMENT OFFICESPractical WirelessArrowsmith CourtStation ApproachBroadstoneDorset BH18 8PW(0202) 659910(Out -of -hours service by answering machine)
CREDIT CARD ORDERS(0202) 659930(Out -of -hours service by answering machine)FAX (0202) 659950
EditorRob Mannion G3XFDArt EditorSteve HuntTechnical Projects Sub -EditorNG ("Tex") Swann G1TEXProduction/NewsSharon GeorgeEditorial AssistantDonna Vincent
Advertisement ManagerRoger Hall G4TNTPO Box 948London SW6 2DS071-731 6222Cellphone (0850) 382666FAX 071-384 1031
Advert Copy and Sales (Broadstone Office)Lynn Smith (Sales), Ailsa Turbett (Production)(0202) 659920FAX (0202) 659950
MARCH 1993 (ON SALE FEBRUARY 11VOL. 69 NO. 3
ISSUE 1032
NEXT ISSUE (APRIL)ON SALE MARCH 11
53 Maritime Mobile -Amateur Radio All At SeaMike Harris GOHOC explains a few of the
practicalities of taking radio equipment to sea
57 Broadcast Round -UpPeter Shore Invites you to his new -look column
on the short wave broadcasting bands
59 Packet PanoramaRoger Cooke G3LDI delves into the world of
digital communication and packet radio
60 VHF -UpDavid Butler G4ASR reports on the fascinating
activity taking place on the v.h.f. bands
62 HF BandsPaul Essery GW3KFE's guide to what's
happening and how to be successful on h.f.,whether it be ORP or ORO
64 Valve & VintageRon Ham and readers look back at the good old
days of valve radios and wet and dry batteries
Other Regular Features69 Arcade, All PW services under one roof75 Advert Index19 Club News13 Competition13 Keylines16 Newsdesk '9349 Radio Diary14 Receiving You
Front Cover: Our thanks go to SGC Inc., of SGC
Building, 13737 SE 26th St., Bellvue,
Washington USA, for the photographs of theSG -2000 h.f. transceiver, which we plan to
feature In a future issue.
We apologise, that due to space limitations,
the 'Basic OSOs In French' and 'The Mobile
Microphone Project' have been held over.
Copyright St PW PUBLISHING LTD. 1993. Copyright in all drawings, photographs and articles published in Practical Wireless is fully protected and reproduction in whole or partis expressly forbidden. All reasonable precautions are taken by Practical Wireless to ensure that the advice and data given to our readers are reliable. Wecannot howeverguarantee it and we cannot accept legal responsibility for it. Prices are those current as we go to press.Published on the second Thursday of each month by PW Publishing Ltd., Arrowsmith Court, Station Approach, Broadstone, Dorset BH188PW. Tel: 102021659910. Printed inEngland by Southemprint Web Offset) Ltd. Distributed by Seymour, Windsor House, 1270 London Road, Norbury, London SWI6 4DH, Tel: 081-679 1899, Fax: 081-6798907, Telex:8812945. Sole Agents for Australia and New Zealand - Gordon and Gotch (Asia) Ltd.; South Africa - Central News Agency. Subscriptions INLAND £21, EUROPE £23,OVERSEASIby ASP) £25, payable to PRACTICAL WIRELESS, Subscription Department. PW Publishing Ltd., Arrowsmith Court, Station Approach, Broadstone, Dorset BH18 8PW. Tel:102021659930.. PRACTICAL WIRELESS is sold subject to the following conditions, namely that it shall not, without written consent of the publishers first having been given, be lent, re-sold, hired out or otherwise disposed of by way of trade at more than the recommended selling price shown on the cover, and that it shall not be lent, re -sold, hired out orotherwise disposed of in a mutilated condition er in any unauthorised cover by way of Trade, or affixed to or as part of any publicationor advertising, literary or pictorial matterwhatsoever. Practical Wireless is Published monthly for $45 per year by P.W. Publishing Ltd. PW Publishing Ltd., Arrowsmith Court, Station Approach, Broadstone, Dorset 8H188PW, U.K. Second Class postage paid at Middlesex, N.J. Postmaster: send address changes to Practical Wireless, c/o C & C Mailers International Inc., 900 Lincoln Boulevard,PO Box 177, Middlesex, N. J. 08846 USA. (The LISPS (United States Postal Service) number for Practical Wireless is: 0070751.
Practical Wireless, March 1993 1
NORMAN G4THJ
400 Edgware Road, London W2Telephone: 071-723 5521 Telex: 298765
Opening times: 9.30am-5.30pm Mon -Fri. 10am-4.30pm Sat.
Normally24hr
despatch butplease allow
7 days fordelivery.
IFILPJLVVUNLIKUIVI-tii STANDARD.
Transmitter:
Banderwith
£429
C558Twin
AM
VHF UHF
RF Power Output Battery Type Hi Mid Lo Hi Mid Lo
CBT151GY 2.0W 2.0W 0.35W 1.5W 1.5W 0.35W
CBT150 15W 25W 035W 2.0W 2.0W 0.35WCNB151GY 2.5W 2.5W 0.35W 2.0W 2.0W 0.35W
CNB1S3 2.5W 2.5W 0.35W 2.0W 2.0W 0.35W
CNB152 5.0W 2.5W 0.35W 5.0W 2.5W 0.35W
Receiver: VHF section Ulf section
Circuitry Double Conversion Superheterodyne
Intermediate Frequency 1st IF 21.80 MHz 23.05 MHz
2nd IF 450 kHz 450 kHz
Sensitivity (12dB SINAD) 0.15130
Threshold Squelch Sensitivity 0.11201
Selectivity (2 -signal method) 55 dB SO dB
Audio Power Output 200 mW at 10% distortion
S/N Ratio at 0.50 Input 25 dB
C500 Accessories
CLC500 Carrying case C500
with CNB111 batter
CLC501 Carrying case C500
with CNB120 battery
CMP111 Speaker microphone
CMP113 Tie -pin microphone
CMP115 Speaker microphone (small size)
CNB111 Nicad battery pack
(3.5W-VHF/3.0W-UH
CNB120 Nicad battery pack (5
EBATT Empty battery case for dry cells
CSA111 Desk top charger CN8111
and CNB120 battery
C102/230-1 Plug-in charger CNB111 battery
CWC20 Plug-in charger CNB120 battery
CAD111 Charging adaptor for battery only
CAW1208 Mobile adaptor for direct use
from car battery
CMC01 Mobile charger car battery
to CNB111 battery
CM8111 Mobile bracket
CHP111 Headset with P.T.T switch
CTN503 CTCSS tone squelch unit
CTD500 Touch tone unit for use r Mobile/Fixed Equipmentwith remote control
Model Mc...Price inc. VAT Model No:...Price inc VAT C150IC528 AccessoriesC558 E429.00 CNB182 £65.00 CLC151 Carrying case C150 with CNB151 batt.
C528 (399.00 CNB183 . £59.00 CLC152 Carrying case C150 with CNB152 batt.
C188 E269.00 CNB184 £39.00 CLC528 Carrying case C528 with CNB151 batt.
CTN520 f50.00 CMC150 £14.10CLC521
CMP111
Carrying case C528 with CNB152 batt.Speaker microphone
CBT151 E12.50 CWC151 £17.50 CMP113 Tie -pin microphone
CBT151G £12.50 CMU181 £17.50 CMP115 Speaker microphone (small size)
CNB151 f45.00 CHP111 f39.36CMB111
CMC150K
Mobile bracketMobile charger for CNB150/151/153
CNB151G £45.00 CHP150 £47.50 CHP111 Headset with P.T.T. switchCLC550 f12.99 CSA160 £70.50 CNB151 Nicad battery pack (7.2V-700mAH
C98152 £72.00 CCA160 £12.00 CNB152 Hi -power battery pack (12V-600mAH)
CWC150 £14.68 CAX03 £4.50CBT151
C5A160E
Empty battery case for dry cellsDesk top rapid charger for C150/C528
CAW150 £14.10 CAX160 £27.50 (replaces CSA150)
CAW151 f9.50 CBH160 E7.50 CWC150 AC charger CNB151 battery
CLC520 £12.99 CMU160 £17.50 CWC151 AC charger CNB152 battery
CLC521 f12.99 CMU161 £22.50CTN150
CTN520
CTCSS tone squelch unit
CTCSS tone squelch unitCMP111 f35.25 CNB160 £40.00 CTD150 DTMF unit for C500
CMP113 £35.25 CNB161 £45.00 CAW150 Power cable for mobile use
CMB111 £14.69 CNB162 £79.00CAX02 Battery contact covers
Docking amplifier for C528CSA181 175.00 CTN160 £50.00 30 watts on either bandCCA181 £11.95 C168 f269.00
CLC182 £12.99 C468 f279.00 GINHIP AND JAYBEAM ANTENNASCMA181
CMU182
f21.95
E2230
CTN5600 £47.50
& ACCESSORIES STOCKED
March13th & 14th
LONDOAMATEUR RADIO& COMPUTER ,
C164/468 Accessories
CLC160 Carry case for use with CNB160
CLC161 Carry case for use with CNB161
CLC162 Carry case for use with CNB162/163
CNB160 Nicad battery pack (6V B 300ma)
CNB161 Nicad battery pack (7.2V it 700ma)
CNB162 Nicad battery pack (12V B 600ma)
CWC150K Wall charger for CNB160/161/163
CWC151 K
CSA160E
CAW150
CHP150
CMU160
CMU161
CAX03
CAX160
CAW150
CCA160
CTN160
CMP111
CMP115
CHP111
CMP113
CMB111
Wall charger for CNB162
Desk top rapid charger for all nicads
Mobile power supply cable
Headset with PTTNox
Memory unit - 30 channels
Memory unit - 200 channels
Button cover
Remote battery adaptor
Mobile power cable
Charging sleeve
CTCSS module
Standard size speaker/mic
Small speaker/mic
Headset boom/mic
lie -pin mic and earphone
Mobile bracket
C5608D Dual band UHFNHF 45W
mobile transceiver RX
coverage extendable
C188/448Series
C188
£269C448
£279Receiver:
NI3TANDASIO
C188 Series C488 Series
Intermediate Frequency 1st IF
2nd IF
44.95 MHz 44.95 MHz
455 kHz 455 kHz
Sensitivity (12dB SINAD) 0.158pV
Threshold Squelch Sensitivity 0 112pV
Selectivity (2 -signal method) 55 dB 55 dB
SIN Ratio at 0.5 pVInput 30 dB
Audio Power Output (10% Distortions) ISO mW
Transmitter: C188 Series C488 Series
RF POW Output Hi Mid Lo Hi Mid towith CBT181 12W 1.2W 0.15W 1.2W 1.2W 0.15Wwith CBT182 1.5W 1.5W 0.15W 1.5W 1.5W 0.15W
with C98181 12W 1.2W 0.15W 1.2W 11W 0.15Wwith CNB182 5.0W 2.5W 0.15W 5.0W 25W 0.15W
with 08183/184 25W 2.5W 0.15W 2.5W 2.5W 0.15W
Performance specifications are nominal, unless othewise indicated,and are subject to change without notice.
We are a main agent for ICOM, KENWOOD,YAESU, ALINCO and all popular brands ofscanning receivers, SWR meters and aerials, plus alarge selection of plugs and sockets.
Lee Electronics2 Practical Wireless, March 1993
For the very best in Communications ReceiversLook to Lowe
LOWE HF RECEIVERS DO IT AGAIN!HF-225 voted "RECEIVER OF THE YEAR" in 1990 by W.R.T.H.HF-225 "FINLANDIA" voted "BEST DX RECEIVER 1992" atthe EDXC Convention in Finland. Final choice was fromHF-225, NRD-535 and IC-R72E.
ONCEAGAINTHE BEST ISBRITISH!
LOWE ELECTRONICS LIMITED
LOWE
Chesterfield Road, Matlock, Derbyshire DE4 5LETelephone: (0629) 580800 Fax: (0629) 580020
BRANCH ADDRESSES:London (Middlesex): 223 Field End Road, Eastcote. Tel: 081-429 3256
London (Heathrow): 6 Cherwell Close, Langley. Tel: (0753) 545255Newcastle: Newcastle International Airport. Tel: (0661) 860418Cumbemauld: Cumbernauld Airport Foyer. Tel: (0236) 721 004
Bristol: 6 Ferry Steps Industrial Estate. Tel: (0272) 771770Cambridge: 162 High Street, Chesterton. Tel: (0223) 311230
Bournemouth: 27 Gillam Road, Northbourne. Tel: (0202) 577760Leeds: 34 New Briggate, Leeds. Tel: (0532) 452657
LOWE
7A TWO-WAY RADIO AMATEUR RADIO AUDIO VISUAL SALES & SERVICE58 High Street, Newport Pagnell, Bucks MK16 8AQ. Tel: (0908) 610625 FAX: (0908) 216373
Communications Centre (Photo Acoustics Ltd.)
SKY SCANDesk Top Antenna Model Desk 1300
Built and designed for use with scanners. Coverage: 25 to1300MHz. Total height - 36ins - 9ins at widest point. Comescomplete with 4 metres of RG58 coax cable and BNC connectorfitted. Ideal indoor - high performance antenna and can also beused as a car antenna when your car is static. REMEMBER YOURSCANNER IS ONLY AS GOOD AS YOUR ANTENNA SYSTEM!
£49.00 + £3.00 p&p
SKY SCANV1300 Antenna
AMost discones only have horizontal elements and this is thereason that they are not ideal for use with a scanner. Most ofthe transmissions that you are likely to receive on your scannerare transmitted from vertically mounted antennas. The SkyScan V1300 discone has both vertical and horizontal elementsfor maximum reception. The V1300 is constructedfrom best quality stainless steel and aluminiumand comes complete with mounting pole.
Designed and built for use with scanners.
£49.95 + £3.00 p&p
SKY SCANMagmount MKII
For improved performance, wide band reception, 25 to 1300MHz. Comescomplete with protective rubber base, 4m RG.58 coax cable and BNCconnector. Built and designed for use with scanners.
£24.95 + £3.00 p&p
HF PACKAGE DEALS
Super deals on above!TS -850 Super deal with P.S.U. £1599.95
SECONDHAND EQUIPMENTSony Air -7 Airband Handheld 179.00(corn IC-2SET 2M Transceiver 199.00Kenwood RZ-1 Scanner 235.00Trio TH-21E 2M Handheld 139.00Yaesu FTV-901 R 2M Trans 235.00Kenwood TH-21 E 2M Handheld 115.00HF-125 Receiver 275.00lcorn IC -32E 2M/70CMS Handheld 365.00BNOS 12/6A 6AMP Power supply 49.00AR2002 Scanner 255.00Sommerkamp FT -767 HF Trans. 399.00AR -3000A HF/VHF/UHF Scanner 785.00Yaesu FT -290R1 c/w 10W Linear 315.00AR -3000 HF/VHF/UHF Scanner 695.00VC I ATU 95.00MVT-8000 VHF/UHF Scanner 259.00Sony Air -7 Receiver 179.00Standard C520 Dualband H/H 269.00Tokyo HX240 Transverter 195.00Trio TR2400 Tran + Acc 95.00Welz SP -220 SWR/Power Meterlcorn IC-2SRE 2M H/Hand Broadband VHF/UHF Scanner
49.00
350.00Kenwood TS -440S HF Transceiverc/w Narrow CW Filter 790.00
ALL OUR SECONDHAND EQUIPMENT HAS A
THREE MONTHS PARTS & LABOUR WARRANTY
HANDY STAND HB-100Your Handheld BecomesA Base Station!
It's so simple yet nobodyever thought of it untilnow! Comprises universaladjustable angle mountwith rubber feet and nonescratch surface. BNC leadand SO -239 base socket.The smartest gadgetwe've seen for years.
£24.95 Post £2.50
NEWFT530
VHF/UHF Handheld
Built in CTCSS MH29A2B Dual Reception on
same or differentbands, independentVol/SQ controls foreach band
MH29A2B for FT530Handspeaker/microphone. LCDdisplay. Duplicates mostused front panel keys.
£425.00At time of going to press woes aretoect but may be subtect to change due
currencyfluctuations
* Auto repeater mode * AM Alrband Reception* Expanded Receive to 995MHz
ALINCO DJ -580EUK 'Gold Sear Warranty
Now with every unitLook for the span w the be,'
SpecificationTx 144-146MHz
430-440MHzRx AM 108.143MHz
FM 130.174MHzFM 400-470MHzFM 810-995MHz
Steps 5, 10, 12.520, 25KHz
Memories 42Power Output
2.5/1.0/0.3 Wafts5 Watts with 12V DC
Scan 8 ModesTones 1750Hz plus DTMF
Optional CTSSSensitivity
12dB SINAD-15dBuSize 140 x 58 x 33mmWeight 410gAccessories Supplied
Ni-Cad pack. ACcharger, belt clip,carry strap. dualband antenna
E.409.9 CARR.ul FREE
KENWOOD TH-78E Dual Frequency
Receive on sameband or different
Alphanumericmemory
50 multifunctionmemory channels
DTSS
Pager function
Alphanumericmessage paging
CTCSS (optionalunit)
Up to 5w output
£429.95 FREE
AUTHORISED AGENTS FOR KENWOOD, ICOM, YAESU & ALINCO. FULL SERVICE FACILITIES AVAILABLE
SPEND UP TO £1,200 INSTANTLY WITH A PHOTO ACOUSTICS LTD. CREDIT CHARGE CARD
PART EXCHANGE WELCOME, ASK FOR KERRY G6IZF OR ANDY G4YOW
RETAIL SHOWROOM OPEN MONDAY - FRIDAY 9.30 - 5.30, Saturday 9.30 - 4.30
Goods normally despatched within 24 hours. Please allow 7 banking days for cheque clearance. Prices correct at time of going to press - E&OE
4 Practical Wireless, March 1993
ALINCOALINCOELECTRONICS
2m & 70cms DualBander DJ -580E
£409inc VAT
The DJ -580E hand-held is the mostadvanced design ever offered to the
radio amateur. Building on the winningformula of the DJ -560E, ALINCO have
now reduced the size dramatically andintroduced a combination of
innovative features that will makeyour operating even more fun and
certainly more versatile.
It goes without saying that ALINCO offeryou all the standard features you expectfrom a hand-held including dual watch,
dual controls, scanning, searching, priority,etc. Of course ALINCO's standard of
engineering and reliability is now becomingthe envy of its competitors. (They're also
pretty envious of ALINCO's prices!)Naturally you get a full 12 month warranty
including parts and labour. It's the extrafeatures that really make this a winner.
For example you now have ALINCO'spatented circuit that retains full operationwith dry cells even when battery voltage
falls by 50%. Great for emergencyapplications. You get a programmable auto
power off feature, battery saver, digitaltelephone dialler and three output power
levels. And we've only just started! Key in aspecial code on the keypad and your rig will
turn into a fully operational automaticcrossband repeater. Key in another code
and you will open up the receiver for a.m.airband reception and frequency segmentsup to 995MHz! You can even use the DTMFfeature to send and receive two digit code
messages.
To learn more about thetransceiver that has already
taken the Japanese andAmerican markets by storm,
phone or write for a full colourbrochure.
"The MostComprehensiveSpecification EveLOffered!"Available direct or from your localdealer
Auto repeater modeAM Airband ReceptionExpanded Receive to 995MHz
UK "Gold Seal"Warranty
Now with every unitLook for the sign on the box!
SpecificationTx
Rx
Steps
144-146MHz430-440MHz
AM 108-143MHzFM 130-174MHzFM 400-470MHzFM 810-995MHz
5, 10, 12.5, 20, 25kHz
Memories 42
Power Output2.5/1.0/0.3 Watts5 Watts with 12V DC
Scan 8 Modes
Tones 1750Hz plus DTMFOptional CTSS
Sensitivity 12dB SINAD -15dBu
Size 140x58x33mm
Weight 410g
Accessories SuppliedNi-Cad pack, AC charger, belt clip,carry strap, dual band antenna.
WATERS & STANTON ELECTRONICS
22 Main Road, Hockley, Essex. Tel: (0702) 206835Retail and Mail Order: 22 Main Road, HOCKLEY, Essex SS5 4QS. Tel. (0702) 206835 / 204965
Retail Only: 12 North Street, HORNCHURCH, Essex. Tel. (04024) 44765VISA & ACCESS MAIL ORDER: 24 Hour Answerphone. Open 6 days a week 9 am - 5.30 pm
Rail: Liverpool Street/Hockley or District Line/Hornchurch
WATERS & STANTONUK's LARGEST SELECTION
We can supply almost anything in this magazine within 24 hours!QRP CORNER
---4116-.
MFJ 40m or 20m CW Transceivers.Both models now available with full vfo controland semi -break in. 5 Watts 1199Jim -40m or 20m SSB/CW TransceiversComplete in every respect Inc. CW button andInternal mic. 2 Watts output. 1.249
Ramsey 80m, 40m, or 20m Tx. kits.A complete kit with board, components, controlsand xtal. I Watt output 129.95Ramsey DC 80m, 40m, or 20m Receiver kits.All you need to build a simple hf receiver that willcopy CW, SSB and AM. 129.95
Ask for QRP leaflet
Used Equipment 3 Month WarrantyTS -440S HF with auto atu £849MX -14S Mizuho GRP 20m £169MX -7S Mizuho ORP 40m £169IC -751A HF + Gen coy. Rx £999TS -930S HF + box & book £999FT -767 HF + 6m module £1299TenTec Omini-5 HF As new £1395FT -707 HF Mobile/base £379AT -150 Auto atu £249SP -930S external speaker £69SM-220 Station Monitor £299FC-902 HF atu + swr & pwr £149MC -60 Kenwood base mic £69PS -55 Morn heavy duty psu £149FTV-107R transverter £159HX-240 2m - hi transverter £189FTV-707 2m transverter £149DJ -100E 2m handy £139IC -2E 2m handy £119TH-75E dual bander £249TR-2400 2m handy £119FT -811 70cms handy £219FT -208R 2m handy £119DJ -160E 2m handy £159DJ-160EA 2m + airband £179TH-215E 2m handy £169TR-2500 2m handy .£149
MFJ 1278 Multi modeData Controller
£299.95,.........,,,-- -
,..., .
4:*The MFJ-1278MEI-1278 is the most comprehensive data controller ever offeredby us. It has more modes than any other model and is now outsellingall other competitive units. You get 9 modes: Packet (Including mailbox) FAX, AMTOR, SSTV, RTTY, NAVTEX, ASCII, Electronickeyer, CW reader, plus a feature packed specification. Now is theideal time to try all these interesting modes from one single box.Watch the data and pictures come up on the screen: converse withfellow hams around the world and get the most out of your vhf or hfstation. Amazing value, and even more amazing performance. We canalso supply matching software package, software manual and cablesfor IBM 232 pen at an inclusive price of £299.95.
MFJ Products from Stock!300WHF ATU
ilY.tOalg.xl n
,
11. :t.1104'Ob' 0 0.The MF.1-948 is a complete 300 Watt aerial matcher in onebox. It will match coaxial, balanced feeder and single wires.A dual needle VSWR/Power meter makes adjustmentsimple and a 3 way aerial switch completes the package.Fantastic value! 1'139.95Other MFJ Products:MFJ-949DME1-9018MFJ-264MF1-2608MFJ-816MFJ-812BMFJ-110MFJ-32MFJ-1286MFJ-t281MFJ-1040MFJ-1020AMFJ-12728MFJ-722MFJ-752CMFJ-207MFJ-557MFJ-407BMFJ-931BY -1
MFJ-704MF1-1088
ATU as above but with 300W dummy loadATU less switch load and meter. Super!1.5kW dummy load. DC-650MHz300W dummy load DC-160MHzHF 30/300 Watt power meter144MHz 30/300 Wan power meterFabulous world clock with mapPacket radio handbook. Super guide!Gray Linc Graphics Programme for IBMEasy DX logging programme1.8-54MHz tx/rx preselectorIndoor active antenna station. 0-30MHzTNC/Microphone interfaceSuperb rx audio filterTuneable audio filterAntenna analyzer. Brilliant idea!Self contained CW practice key and oscillatorElectronic keyer. 8.5 -WPM Self poweredArtificial HF ground unit. Ideal for flats etc.Genuine Bencher Paddle. A precision productHF Low Pass FilterDual time deck top clock. LCD Display
TONNA BEAMS
al
VHF/UHFAll with "N"connectors"THE BEST"
20505 5 el
2M20804 4 el20808 4 el20809 9 el20089 9 el20822 II el20813 13 el20817 17 el
Ek.0120909 9 el29919 19 el
23cm20623 23 el20655 55 el
Ten -Tee Omni -VI g-b,i160-10m 0-100W ZL,44.Y3
The OMNI VI is different from any other hi transceiver you have usedor ever seen. Craftsman built, it employs beautifully assembled circuitboards that are easily accessible should you ever need to servicethem. The factory actually encourage you to take the covers off andexamine the craftmanship. No mass production here!
Receiver experts agree that good old crystal mixing can't be beatenand using this method the phase noise has essentially beeneliminated. The OMNI-VI can receive signals on todays crowdedbands that other popular models can't even hear. Great for contestsand DXI A truly quiet receiver.
Delta -II HF /inf.160-10m 100W Z1047Z
(II
The Delta -II is ideal as fixed or mobile. Its rugged design and Ten-Teclabel make it an obvious choice for those who demand quality andcraftmanship. The receiver boasts a continuously variable IF filter witha range of 500-2500Hz. You'll also love the silent break-in operation,the notch filter, passband tuning and wideband receive. Send todayfor colour brochure.
Kenwood HF Bargainsplus our own warranty
and backup service you're safe with us.
TS -850S £1499.95
Amazing value and performance. It outsold all other rigs in1992 - and with good reason! Absolutely no vices. If youwant the internal ATU add 140.
TS450S £1179
We love it, and so will you. Compact, but comprehensive,it's a great way of enjoying the Kenwood reputationwithout going too much over a £1000! Add £140 for ATU.
I've been selling and operating hf gear for years. My priceswill give you a good discount whilst still enabling my staffto give the backup I myself would expect as a customer.You're safe with us!
Peter Waters G3OJV/GOPEP
GSRV With Compact Option!Full Sizeao-iom 102ft £21.95Half Size40-10m £19.50
COMPACT OPTIONUsing our EL-40XC coils you can operate the half size version on 80metres without affecting its performance on the other bands. Thelength is increased by only a few feet but as this added length of wiremay be dropped vertically at the end. the overall length remains thesame. 80-10m in 66ft of space! Coils £18.95 per pair.
AMERITRON HF LINEARS
600 Watts
£799!AL -811
11E11111:1;i,-77:7
This linear is incredible value. We have put it throuh its paces and itreally stands abuse. 3 rugged 811A tubes provide up to 600 Wattsoutput from 160-10m. A hunky mains transformer and full metering isincluded. Used by DX-peditions it has to be amazing value at£799 Inc VAT
AL-80BX 1kW from 160-10m 3-500z tube. £1499.00.
Other Ameritron linears are available. Send SAE today.
AZDEN£239,95!
DirectFactory Prices!
PCS-7000
2m FM 25 W Auto Tone -burst AM Airband Rx Scanning FM 138-174MHz Programme Shift 20 Memories Mic & HardwareThe AZDEN PCS-7000 is possibly the most underated rigavailable. It is simple to operate and can store tone -burstinformation in its memory. In order to promote it we are, for alimited period. offering you the chance to purchase at "factoryprices." There's no catch: these are genuine current productionmodels complete with all accessories plus our money backwarranty if goods returned within ten days. How's that for an offer!
I)Ii%.MOM)BASE STATION ANTENNASCP-S 10-15-20-40-80m vertical with radials £229.95CP-6 6-10-15-20-40-80m vertical with radials 1249.95D -130N Discone 25-1300 MHz. 50 FT cable £94.95CP-22E 2m 2 x 5/8 6.5dB gain omni directional £49.95D-707 Active rx. 1.5-1300 MHz I2V £109.95
FIBREGLASS VERTICALSX-50 2m/70ems 4.5/7.2dB gain i.7m long £69.95X-300 2rn/70cms 6.5/9dB gain 3.Im long £109.95
X-510 lm/70cms 8.3/1I.7dB gain 5.2m long £159.95X-700 2111/70ems 9.3/13dB gain 7.2m long £295.95V-2000 6m/2m/70cms 2.15dBi/6.2dB/8.4dB 2.5m £109.95X-5000 /m/70cms/23cms 4.5/8.3/I.7dB I.8m £129.95
"Antique Radios" 44,Grace your shack with a genuine workingreproduction of yesteryear.
£39.95 Carriage £5Real wood veneer and a proper 'Antique'working dial, built-in speaker and 230 Voltoperation. You get full coverageof FM andAM broadcast bands. Ideal for shack ordomestic use. Model NR -1451190x1Y5x£05mm) illustrated. ModelNR -300-2B (310x300x182mm) £59.95
Head office: Retail and Mail Order: 22 Main Road, Hockley, Essex SS5 4QS.Tel: (0702) 206835/204965. Fax: 205843
Retail only: 12 North Street, Hornchurch, Essex. Tel: (0708) 444765
ELECTRONICS 0702 206835or 204965
OF HAM RADIO PRODUCTS
,#N14\ Highly SensitiveFrequency Counter
Optronics "2300"Self powered - it can sniff frequenciesfrom over 100ft! IMHz - 2.4GHz
£149.95 Inc. ni-cads & charger
((rTransmitted Power
DISCOUNT PRICE!Lavc.o
ALINCO DJ -180E 2m HandheldELECTRONICS GmbH
£189.95* LCD Display* 10 Memories* Repeater Shift* 2 Watts Output
Free Ni-Cads Free ChargerFree Delivery
* Ni-Cad Pack* AC Charger* Auto Power Off* Battery Warning
* 5kHz-25kHz steps* Superb Audio* Helical Aerial* 132 x 58 x 33mm
At this price the ALINCO DJ -180E represents your last chance to purchasea top brand name handheld at yesterday's prices. The DJ -180E offers morefeatures per Pound than any other rig. Take advantage of this offer andpocket the difference. You'll get a superbly engineered radio with a qualityname and our 12 month warranty. There are plenty of accessories to followincluding a memory expansion module to give you 50 or 200 channels.Offer subject to current stocks only.
MaplinElectronics
SENDER - 145
£169.95!FACTORYPRICES
2 Metres
5 Watts
Rx 130-169Mhz
Full Warranty
70 Cms ModelSENDER -430
£179.95This new exciting handheld from MaplinElectronics is offered to you at a directfactory price. And with the current exchangerate you will agree that this is amazing value.You get a proper English handbook, twobattery packs (4 and 6 x AA cells) helicalaerial and carry strap.
Direct keypad entry, 20 memory channels,1750Hz tone, 5 Watts on 12 Volts andcomprehensive scanning all go to make this aunique radio at a unique price. And you'lllove its small size (84 x 55 x 31mm) andrugged construction. Other features include:Battery Save, Dual off, Rotary Dial, 6 channelsteps, Split frequency, 3 power levels, DialLight etc.
NEW! .LINCOALINCOELECTRONICS GmbH.
Special OfferThe DJ-F1E is outselling anyother 2 metre handheld westock. Its performance,reliability and construction areunsurpassed. So convinced arewe that the DJ -FIE offers thegreatest value ever, we arehappy to offer you a full refundif you are not immediatelyhappy with its performance orfeatures. That's right, return thetransceiver to us within 10 daysof purchase and we'll offer youa refund or an alternative, thechoice is yours! That'sconfidence. Peter G30.JV
DJ-F1E 2m FM* Tx: 144-146MHz * Reverse Repeater
* Rx: 108-174MHz * 8 Scan modes
* 5 Watts output (12V DC) * Battery Saver* 40 Memories * S meter* 3 way Power Setting * Priority Channel
* Illuminated Key Pad * Fast tune function* 6 Programmable steps * Rotary Dial* Programmable Shift * Illuminated LCD* 1750Hz tone * Quick touch Squelch
* Frequency Lock * Protected Output
* PTT Lock * BNC socket* Beep on/off * Ni-Cad Pack 700mAh
* Automatic Lamp * AC Hod Charger
* DTMF Tones * Many Accessories
FREE! Mail Order Price List. From UK's LEADING HAM RADIO STOREImportant Notice: some prices may be subject to alteration owing to exchange rate variations. Please check when ordering.
The CompleteVHF/UHF
Frequency GuideThe UK's Largest Selling
Scanning Directory
* Completely Updated* Thousands of Frequencies* 26MHz - 2250MHz* Full Duplex Information* Air, Sea and Land* Military & Civil* Government & Commercial* Emergency & Security
Famous throughout the world of radio, this latest edition is better thanever before and carries all the latest information. A must for allscanning enthusiasts. Do not confuse this with some poorly printedliterature around: this is a properly printed professional guide thatcontains more information than any other publication of its kind. Usedby enthusiasts and professional bodies; there is no substitute for thisguide. Order your "fresh off the press" copy today for delivery inFebruary.
£9.95 Postage £1 .50
RAMSEY KITS USA* All components* Hardware & Boards* Proper Manuals* Cases extra
Brings Back the funin Ham Radio
Anybody can build these kits. They are simplebut very effective. Use alone or as a basis forlarger projects. Full back-up service.
AR -1 Airband AM Receiver. Superhet withsquelch volume and tuning controls £24.95FR -1 FM broadcast receiver. Ideal as noviceproject. Will drive a loudspeaker easily 621.95FR -146 Complete 2 metre receiver plusextra coverage. Dual conversion withceramic filter £29.95HR -Series D.C. SSB/CW/AM receiversfor 80. 40 or 20m (Specify which band) £29.95QRP-TX Complete 1 Watt vxo transmittersfor 80. 40 or 20m (Specify which band) .£29.95P -IBM The famous Packet Radio kit.Self -powered with software £59.95
Add £2.00 Postage & Insurance
VISA & ACCESS MAIL ORDER, 24 Hour Answerphone, Open 6 Days a Week 9am-530pm.
Rail: Liverpool St/Hockley or District Line/Hornchurch
MARTINTel: 081 566 1120 FAX (24Hr): 081 566 1207
Why Wait Nine MonthsWhen You Can Have It In.
I've extended the buy now, pay over ninemonths with NO INTEREST for MARCH only.Why wait another nine months and see yournew radio go up in price again? Come toPicketts Lock, (or phone or call in at the shop),bring some ID with you (a drivinglicence/phone bill will do), bang a depositdown and subject to approval from the gang atTRICITY FINANCE, you can take your 'new baby'home with you - and PAY NO INTEREST ON THEWHOLE DEAL!
THE NEW YAESU FT736R DX
A Lynch + muTek developmentwhich gives
the standardFT736R the competition
performanceit deserves. Mike Dorset from
muTek, will be present on Saturday at
Picketts, to demonstratethe remarkable
improvementhis design and development
team have spent months in the making. If
you've got an FT736R, you won't want to
use it without the new muTek Front -End
Boards! Why not bring your FT736R along
for modification- you'll be without it for 10
days, but it's worth the wait! FT225RD's
taken in part-ex!
My third year at the Picketts Lock Exhibitionand one you will not want to miss. The NORTHLONDON SHOW is THE exhibition of the year -it has all the trade stands you'll ever want tosee - especially mine!This year I have some exciting NEW productson demonstration, several by the designersthemselves!
THE NEW MICROKEYFrom Airwave
Systems is a superb
electronic keyerwith a difference
- it hasn't got 50 buttons on the
front for programming!Using the
68HC705 chip,you tell it what
you want, by the KEY ITSELF.
Many in use by top CW
enthusiasts,built in a sturdy, RF-
proof case and assembledin the
UK to commercial standards.
See it demonstrated by Dave
Bowman, the designer himself, at
Picketts.
YAESU FRG 100
At last a receiver to give the Lowe225 a run for its money, the new receiver from
Yaesu isalready set to break all records for receiver sales.
Remember it was Yaesu
who bought you the FRG -7 back in the seventies, it had to be the equivalent
'Morris Mini' in sales for the Yaesu Musen Company.Come and see it demonstrated
by one of the gang on Lynch's stand!
-WATT NKSLYNCII -G4H
THE AMATEUR RADIO EXCHANGE CENTRE
286 Northfield Avenue, Ealing, London W5 4UBMon - Sat. 10am - 6pm. Late Night Thursday
Tel: 081 566 1120. FAX: 081 566 1207. After Shop flours: 0860 339 339
THE ICOM ICR7100HFMKIIIHas become the benchmark
for Wide
Band Receivers.Now in use by
Government departments, commercial
organisationsand scanner enthusiasts,
the HF conversion by Chris Parnell, has
made the ICR7100HF the 'professionals'
choice. Try it for yourselfand speak to
Chris - he'll be there for both days.
MARTIN LYNCH £25 GIFT VOIT'llERSStill a super way to handle the headache of buyinggifts! No time limit on spending...top-up with anythinglegal!
CALL, WRITE OR FAXfor your 4 -page colour Martin Lynch Newsletter. It'spacked with goodies. bargains and interesting news &reviews. Would you like to contribute?
8 Practical Wireless, March 1993
WE ARE THE CL°5EST
STOREHEATH
Z
R°WTHE pICCADIL" LINE
TO Have Your New B
_ JUSTACROSS
THE ROAD
FROM NCATirmiinFIELDSSTATI°NuNDERGROU.--
byrtantly At Picketts Load;
Tel: 081 566 1120 FAX (2414r): 081 566 1207
YOUR INDEPENDENT
SUPPORTRETAILER
The one whosupported you first!
- lac s- , 1 = "'
letr: 7
WEATHER STATIONS &
MONITORSFrom R&D
Electronics, the UK's No.1
meteorologicalequipment manufacturers,
have a complete range of units suitable
for monitoring all aspects of weather
changes, local to your environment.From
the simple WM-DS, indicatingWind Speed
& Direction,including Gust at only
£189.00, to the top of the range WS -Plus
giving Barometer, Wind Direction/Wind &
Gust Speed,Outside Temp.
Max & Min,
Rainfall, Sunshine+ more, at £599.00. You
cant be a serious DX'er without one! The
full range will be on show at Picketts....
Everything is ondon't be afr
YAESU:The full range, including the FT990,FT890 and their new FRG 100receiver will be on very special offer.Part Exchange is definitelywelcome!
KEN WOOD:ow KenwoodS in the UK,verything is OK! Direct from theirassive Headquarters in Watford,
he full range will be on show, withubstantial savings And there isgn of that new mini HF mobile...
NEWSHASII...NEWSHAS11...NEW HF MINI-MOBILE FROM KENWOOD
DUE IN MARCH...
PHONE FOR LATEST UPDATE.
YAESUFT530Advertised forover six months,now finallyavailable, the new
DUAL BANDERfrom Yaesu. The
only Handie with
a remote digitalreadout SpeakerMicrophoneavailable as anoption! Its alsoavailable on myBUY NOW PAY
LATERSCHEME
ICOM IC-W21Well, what do yer
know... Along comes
another Dual Bander
from ICOM! This one is
very good - it must be,
even I can demonstrate
it! Don't want all the
gizmos on offer by the
competition, but want
top grade performanceat a sensible price? The
boys at ICOM have done
it and you can buy it on
the 1 0% down - rest in
three months scheme,
only from MARTIN
LYNCH.
DEWSBURY ELECTRONICSThe old ships captain, Tony Dews, won't be at Picketts
this year, but his excellent range of Electronic
goodies will be. Amongst the selection,will be the superb DM1000
Easy Reader. A self contained
unit, the new Easy Reader will convertmost of the funny noises on Short wave that you are hearing
at present, (but just give you a headache!), intoreadable text on a video monitor. The DM1000 from
Dewsbury, is a state-of-the-artconverter that
requires a simple Video monitor,(or TV with the optional
modulator), a 12V supply and your receiver toinstantly give you
access to the world of DATA
Transmissions - its like startingSWLing all over again! My mate Tony might just pop along to shake a
few hands....
SPECIAL OFFERS'a my mum says, if you don't ask you don't get!!
"BUY NOW PAY LATER SCHEME.Don t forget to bring some ID and aBankers Card, (if possible), to walkaway with your new ALINCOMODEL at the show!
ELITE range of used equipment:All used equipment sold by me istested, cleaned and offered with afull money back guarantee. If its notas described, you can have yourmoney back. Nobody offers a betterdeal, or sells as much usedequipment - over 6000 pieces inunder 3 years!
special offer at PICKETT'S -id to ask - like
EXTRA DISCOUNTS or FREE FINANCE,
icom:Now these guys are really comingout with some nice kit. Yes, it doestend to be a little more expensivethan most, but the advancedfeatures and superb engineeringcommand a higher premium.
left...ve some pre -price increase stomcknave
ALINCO:All the Alnico range of HANDHELDSAND MOBILE FM TRANSCEIVERS,including the NEW 0/580E areavailable at Picketts on the special
Practical Wireless, March 1993
I ve been buying and sellingsecondhand equipment probablylonger than anyone. My schoolteacher wrote on my junior reportmany moons ago, -If Martin stoppedselling bits & pieces to the rest of theschool he would do a lot better". Iwonder where Mrs. Robinson isnow?Anyway, suffice to say, if yourselling for cash, you'll get the topprice. Part -exchanging, the sameapplies and I still offer the SALE orRETURN Scheme. No commission, youtell me what you want and when itssold pay you that amount - its easy!
0% 8 *4T E UR TRAFFORD RALLY
*4i) 1 The Great Northern Rally at G-MEX44. n Sunday 21st February 1993
44, e City Centre, MANCHESTER.'gV
E-4 r ot ALL ENQUIRIES on 061 748 9804 or 061 748 8046
ADMISSION £1.50 ALL CLASSES. YOUNG CHILDREN FREE.
OPENING HOURS 10.30 CLOSE 5pm & WE HAVE DISABLED PRIORITY QUEUE.
All usual attractions including free cash draw and bring 'n' buy. Licenced bar,Hot and Cold meals, tea coffee.
Large single ground floor Hall for easy access.30.000 square feet of space, so lots of room!Plenty of parking space both free & paid for.
TALK -IN FACILITIES AVAILABLE ON 2m via GB I GMXIf you have no transport you can still attend. G-MEX, being in the centre of
Manchester, is well served by public transport. including it's ownB.R. stations. PLUS Metro r
transport to G-MEX fromPiccadilly Centre.
SPECIALIST ANTENNA SYSTEMS LTDPresent the finest range of DX antennas and accessories
cushcrcrft40-2CD 40m 2 element Beam20-4CD 20m 4 element Beam20-3CD 20m 3 element Beam15-3CD 15m 3 element Beam10-4CD 10m 4 element BeamTEN -3 10m 3 element BeamA4S 20-15-10m 4 element BeamA3S 20-15-10m 3 element BeamA3WS 17-12m 3 element BeamD40 40m Rotary DipoleD4 40-20-15-10m DipoleD3 20-15-10m DipoleD3W 30-17-12m DipoleR7 40-10m H/W VerticalR5 20-10m H/W VerticalAP8 80-10m VerticalAV5 8 Band HF VerticalAV3 20-15-10m VerticalA50 -6S 6m 6 element BeamA50 -5S 6m 5 element BeamA50 -3S 6m 3 element BeamAR -6 6m Ringo Vertical17B2 2m 17 element Beam13B2 2m 13 element Beam124WB 2m 4 element BeamA144-7 2m 7 element BeamA144-11 2m 11 element BeamA144-207 2m 10 element X OscarAR -2 2m Ringo VerticalARX-2B 2m Ringo Ranger IIAR -270 2m/70cm Vertical424-B 70cm 24 element BeamA430-11 70cm 11 element Beam416TB 70cm 8 element X OscarARX450B 70cm Ringo Ranger II
LIGHTNING ARRESTERS AND FULLRANGE OF COMMERCIAL
ANTENNAS ALSO AVAILABLE.PLEASE ASK FOR FULL DETAILS
ti
CC
M IRAGE/KLMCOMMUNiC.AlIONSIQUIPM1 NI
40M-2 40m 2 element Beam20M-4 20m 4 element Beam15M-4 15m 4 element Beam10M-4 10m 4 element BeamKT34-A 20-15-10m 4 element BeamKT34-XA 20-15-10m 6 element Beam6M-7LD 6m 7 element Beam6M-5 6m 5 element Beam2M-20LBX 2m 20 element Beam2M-16LBX 2m 16 element Beam2M-13LBA 2m 13 element Beam2M -22C 2m 11 element X Oscar2M -14C 2m 7 element X Oscar432-30LBX 70cm 30 element Beam432-20LBX 70cm 20 element Beam435-40CX ..........70cm 20 element X Oscar435-18C 70cm 9 element X Oscar
LINEAR AMPLIFIERSA1015G 6m 10-150w g/f rxB3030G 2m 30-300w g/f rxB3016G 2m 30-160w g/f rxB1016G 2m 10-160w g/f rxB108G 2m 10-80w g/f rxB215G 2m 2-150w g/f rxD3030N 70cm 30w -100wD1010N 70cm 10w -100w1315N 70cm 2w -20w
GASFET PRE -AMPLIFIERS
KP-1/2M 2m Indoor unitKP-1/70 70cm Indoor unitKP-2/2M 2m Masthead unitKP-2/70 70cm Masthead unit
TELEX hy-gain7-2 40m 2 element Beam7-1 40m Rotatable Dipole205CA 20m 5 element Beam204BAS 20m 4 element Beam203BAS 20m 3 element Beam155CA153BAS
15m 5 element Beam15m 3 element Beam
105BAS 10m 5 element Beam103BAS 10m 3 element BeamTH7DXS 20-15-10m 7 element BeamTH5MK2S 20-15-10m 5 element BeamEXP14TH3JRS
20-15-10m 4 element Beam20-15-10m 3 element Beam
TH2MK3S 20-15-10m 2 element BeamDX8812AVOS
8 Band HF Vertical
14AVO20-15-10m Vertical
40-10m Vertical18VS 80-10m Vertical66DX64DX
6m 6 element Beam6m 4 element Beam
215DX 2m 15 element Beam216SAT 2m 8 element X Oscar7031DX 70cm 31 element Beam7030SAT 70cm 15 element X Oscar
ROTATORST2X Windload 1.9m2HAM IV Windload 1.4m2CD45 II Windload 0.79m2AR40 Windload 0.28m2
We now haveGEM QUAD PRODUCTS
Please ask for details
Trefonen, Oswestry, Shropshi e SY10 9DJPhone 0691 670440 Fax 0691 670282
CALLERS WELCOME - PLEASE NOTE OUR NEW ADDRESS
March 13th & 14th
LONDON1 5:
be
OPENING HOURSMon -Fri = 8.30-5.30Saturday = 9.00-1.00
10 Practical Wireless, March 1993
LONDON11 Watford Way,
Hendon,London NW4 3JL.Tel: 081 202 0073Fax: 081 202 8873
THE BESTDUAL -BANDIN THE LAND
Icom IC-W2EThe IC-W2E gives perfect, simultaneous
dual -band receive even while transmitting onanother band. A 3 -way tuning system allows fastselection of frequency or memory channelsusing top panel control, digit keys or up/downkeys. 60 memory and 2 call channels make theIC-W2E a versatile, market -leading transceiver.
ICOM IC -W21 ESimple operation, lightweight and
dependable. The IC-W21E offers easy operationusing only a few switches and independentvolume/ squelch controls for each band. Theergonomic, splash -resistant and tough designmakes the diminutive IC-W21E a snug fit in thepalm of your hand.
Cellphone-style 'whisper' function givesfull duplex crossband operation via the micequipped battery pack,
Easy repeater operation with repeatermemory. Every time you access a repeater allsettings are automatically memorized in anindependent repeater memory, making recall ofthe last used repeater information both quickand simple. All this and loads more in a radiothat is so small, and at a Hamstore NOW!
We also stock items by AEA, AKD, Alinco, AOR, Barenco, Comet, Cushcraft, Davis, DeeComm,Diamond, Icom, JRC, Kenwood, Lowe, Microset, MFJ, RSGB Publications, Sony, Toyo, Yaesu, Yupiteru etc.Second-hand & ex -demo equipment is also available.
Part -exchanges and payment by Access, Visa and Switch welcomed. Finance arranged (subjectto status). Interest free credit on selected new ICOM products. If you cannot visit an ICOM HAMSTORE inperson, why not use our efficient Mail Order Service. Stock items are normally dispatched within 24Hrs.
We give full warranty on all ICOM products bought from authorized ICOM UK dealers. In somecases the equipment will be replaced if the fault is deemed beyond speedy and satisfactory repair. AnyICOM equipment purchased from an unauthorized dealer is not covered by ICOM warranty.
Gordon G3LEQ & John G8VIQ at Birmingham, ChrisG8GKC at Heme Bay and Doug GOLUH & Paul G7MNI in ournew London Store are all looking forward to seeing you.
GREENHILL
HERNE BAYHAMSTORE
I-1 E 12 NE BAYUnit 8, Herne Bay West
Industrial Estate, Sea Street,Herne Bay, Kent CT6 8LD.
Tel: 0227 741555Fax: 0227 741742
OICOM MasterCard
BIRMINGHAMHAMSTORE
BIRMINGHAMInternational House,
963 Wolverhampton Rd. Oldbury,West Midlands B69 4RJ
Tel: 021 552 0073Fax: 021 552 0051
ALL STORES OPEN TUESDAYS TO FRIDAYS 09:00 - 17:00 & 09:00 - 16:00 SATURDAYS. N.B. Herne Bay closed for lunch 1300-1400
SRP. TRADINGSANGEANDirect key
ATS 803A-in world receiver with quartz alarm clock timer
i---
N. N. m.. N. weim .11 EN ,... 1®
SANGEA,
DIMENSIONS: 29.2cmx16.0cm(11.5inx6.3inx2.36in).
skICINIBFO SS . , - OUTPUT: 1200mW (10%THD)'tuneableWEIGHT: 1.7kg (3.75lbs) without batteries.
Wide/narrow filter switch.
£109.95 + £5 check, test and p&p.
Also, suitable mains unit available. only £9.95
Specifications and features* 150-29.999 continuous tuning with no gaps. Phase locked loop -doubleconversion Superheterodyne * Full shortwave/AM/SSB 150-29999kHz nogaps! + FM87.5-108 monoistereo * Five tuning functions: Direct press buttonfrequency input auto scanning, manual scanning memory recall and manualtuning knob * Built-in clock and alarm. Radio turns on automatically at presettime and frequency. * Large digital frequency display. * Fourteen memories -nine memory channels for your favourite station frequencies. Last setting ofmode and waveband stored in five memories. * Direct press -button access toall 12 shortwave broadcast bands. * Two power sources - battery or ACmains adaptor. * General coverage of all AM bands in LW/MW/SW (dedicatedbroadcast band coverage on all versions). plus of course the FM band forquality sound broadcasts in headphone stereo. * SLEEP function turns theradio on or off after an adjustable time of 10-90 minutes. * Separate BASSand TREBLE controls for maximum listening pleasure. * External antennajack for better reception. * Adjustable RF GAIN control to prevent overloadingwhen listening close to other strong stations or if there is interference. * Newimproved wide/narrow filter (6/2.7kHz) * BFO control (Beat FrequencyOscillator) enables reception of SSB/USB/LSWB (single side band) and CW(Morse Code) transmissions. * Illuminated display to facilitate night-time use.* Designed for both portable and desk top use. * Five dot LED signalstrength indicator
SANGEANPortable
Antenna
ANT Greatly
powershortwave
Easytelescopingplug intoantenna7 metres
Portableoutdoors
Suitable
SW-....
Now FREE with "every purchase
of Sangean
60 ATS 80.3A. ..
,------1"
reception
snap ontoantenna orexternal AM
to
and
kinds of shortwave radios El 4.99POST AND PACKING WITH THIS ISSUE ONLY
improveof portable
receiver
hookup torod
radio'sjack extends(23 feet)
for indoors
for all
FREE
SRP Trading, Unit 20, Nash Works,Forge Lane, Belbroughton,
Nr. Stourbridge, Worcs.Tel: (0562) 730672. Fax: (0562) 731002
FT890
-Reg Ward & Co Ltd. -1 Western Parade, West Street, Axminster, Devon, EX13 5NY.
Telephone: Axminster (0297) 34918
(Largest Amateur Radio Shop in the South West)One Stop for Yaesu Icom Kenwood
HF TRANSCEIVERSYAE SUFT890 Compact TXCR
AccessoriesATU2 Autotuner
FP800 Matching PSUFVS2 DI9 Voice StorageSP6 Base Speaker
SP7 Mobile SpeakerFT990 With PSU
Without PSU
FT990
VFW) 41N1
IC728
IC765
ICOMNEW IC728/1C729IC728 HFIC729 HF+6M
AccessoriesPS55 PSUSP7 SpeakerAT150 Auto ATUSM8 Desk MicIC765 HF Base Station
KENWOODTS450/690TS450 HF
TS690 HF.6M
AccessoriesPS31 PSU (SSB only)PS53 PSU (Full Duty Cycle)TS450SP23 Ext. SpeakerAT450 Int. Auto ATUKenwood TS850PS52 PSU (Full Duty)SP31 Ext. SpeakerAT850 in Auto ATU
C:40)TS850 MOEDA Desk Mic
Yaesu FT212RH 2m, 45 wasYaesu FT2400RH New 2m, 50 waftYaesu FT5200R 2m10cm. Full Cross Band
VHF/UHF MOBILES
eFT5200R
ICOM IC229E/HIC229E 2m. 25 wattIC229H 50 watt
ICOM IC3230H 2m/70cm FM, 45/35 Watt
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12 Practical Wireless, March 1993
The amateur radio bands are always under pres-sure. There's always someone, or some pressuregroup who would like to use the frequencies allo-cated to amateurs for themselves.
Many of our frequencies are allocated on ashared basis, and recently. the ever popular430MHz band has come under pressure. In recentyears, '70 cems' has become extremely popular.and nowadays there's a great deal of commercial-ly -made equipment available. Additionally, withthe introduction of the Novice licence, there's evenmore activity on the band.
Unfortunately. apart from the long term mili-tary pressure on the band, there's also an increas-ing demand from private mobile radio and othercommunication interests. To the p.m.r. lobby, thispart of the u.h.f spectrum is very desirable, and itappears that at least one pressure group is deter -
mind to obtain part of our present allocation.So. what can we do about threats to the ama-
teur bands? Obviously, for those who support andbelong to the RSGB, the first point of contact willbe the society. This, to state the obvious, is wherea strong national body helps. With our support. theRSGB and the amateur radio hobby can counteroutside attacks.
However, in my mind a single voice, albeit arespected one, can easily be lost amongst manyothers defending their own cause. Because of this,I suggest that as many 430MHz band users as pos-sible, write directly to the Director of TheRadiocommunications Agency in London to objectto any planned reduction in the 430MHz alloca-tion.
To illustrate my point about lobbying the rele-vant authorities, I'll quote an example close to myown heart, namely railways! The term 'lobbying'
r
comes from the practice of various interest groupsmeeting (to put their point of view across) the indi-vidual members of Parliament and respectiveMinisters of State in the lobby of the Palace ofWestminster.
Unfortunately for the railway industry, the peo-ple representing their point of view (the railway'lobby') are heavily outnumbered by those workingon behalf of the road transport industry. This means,that when it comes to publicity for and against a par-ticular proposal, the railway's 'voice' can be lostamong the many others shouting above it.
With this in mind, I strongly recommend that weall add our voices to that of the RSGB, and tostrongly defend any reduction in our frequency allo-cation on 430MHz. It may come as a bit of a shockto the p.m.r. and other users lobby, that we're not asapathetic as they think we are!
Finally, our front cover tribute last month,together with the very short article on EddystoneRadio aroused so much interest from readers, that Icouldn't ignore it! So. I've passed on your com-ments to Ron Ham, and I've no doubt thatEddystone Radio and their products will soon befeaturing in the 'Valve & Vintage' column. In themeantime, to the very many who contacted me,thank you for writing. I had no idea how much inter-est there would be when we showed the Eddystone750 on the front cover. If we'd had one for sale, itwould have sold many times over!
COMPETITIONCORNERWordsearchWordsearch rules: Twelve different
words have been hidden in the letter
grid. They have been printed across
(forwards or backwards), up and down,
diagonally, but they are always in a
straight line without odd letters in
between. You can use the letters in the
grid more than once for different words.
Once you have found all 12 words, mark
them on the grid and send it, along with
your name and address (photocopies
accepted with the corner flash) to our
editorial address, marked 'Competition
Corner' Wordsearch March '93.
First PrizeA year's subscription to PracticalWireless or a £20 book voucher.
Second PrizeSix month subscription or £10 bookvoucher
Practical Wireless, March 1993
B
N
F
T
X
T
H
S
T
A HS A I R AN MI0 B W G N NE T Y
O P X A EA TI PEX MI J S N R A AER NR H OA VI G R
A E L S MV S X BE
S Q X OIL BEU W X E AML VA 0 D M S I 0 E
E R BR BC MCK G 0 EE I B
L V
C D
X A
N Z
E E
L S MV ST AP E A M A
M K
Z N
L J
I 0
R R
D W
NameAddress
Send your entry (photocopies acceptable withCorner, Wordsearch Competition, March '93,Court, Station Approach, Broadstone, Dorsetwinner is final and no correspondence will beFriday 26th March 1993.
TwelveWords To FindAntennaBargainBasementMaritimeMaxcomMobile
corner coupon) to: CompetitionPW Publishing Ltd., ArrowsmithBH18 8PW. Editor's decision on theentered into. Entries to reach us by
NewsOlympicRepeaterValveVintageWorkshop
Dear SirWhat an excellent ideait is to run the competi-tion corner. For manymonths as a PWregu-lar, I have completedthe competition for fun,but until now have notsent in my entry in forreal!
To be honest I don'tmind if I don't win, butenjoy the taking part.It's rather like some ofour amateur radio con-tests! One addition inPractical Wireless thatwould not take upmuch space, would beto print the answer andlucky winners of thecompetition corner sothat the armchair par-ticipants can verifytheir results and thelucky winners can beglorified in print!Richard BoittierG8CUAHarlowEssex
Editor's reply: ThePW team are pleasedyou enjoy the com-petitions Richard.Donna 'Toad'Vincent was literallyburied under entriesfor the Alinco com-petition as it was sopopular. We try topublish the results in'Newsdesk' (as wedid in the January1993 issue) whenspace permits, andyou'll see themsoon. Best of luck!
Dear SirJust a little bit of advice to all of your readers, sothat they don't have to go through the traumaticexperience of courts to get their money back forbreaches of contract, by second parties.
Whenever a piece of equipment is deposited witha company for repair or for diagnosis of a fault,make sure all your requests are made clear, and thatthere are two copies, one for the company and onefor yourself. The easiest method of doing this is tomake a carbon copy signed by a representative ofthe company.
If you ask for a fault diagnosis, and the companygo ahead and repair the equipment, then they do soat their own volition. Under the law you do NOThave to pay for such a repair.
I state all these facts because I paid for a repairthat was supposedly done to my radio by one com-pany, and had a receive fault put on the set in thebargain. My original request was for a diagnosisreport, estimate as to cost, and no work to be car-ried out in respect of this fault without my authorisa-tion in writing.
I paid to obtain my radio back into my posses-sion, only to find that the original fault still existed,and that the engineer working for the company hadput a receive fault on the set. After nine months ofwrangling, letters from the manufacturer, and start-ing action in the courts for recovery, the companyfinally settled out of court.
My thanks go to John and Barry at CastleElectronics for finding the fault and eventuallyputting things to right, and for showing a greatdegree of expertise. Also to Peter for his great legalmind and the time he gave to bring my case to anend. Be warned!S. Mayer GOHQHNewcastle, Staffs
Editor's reply: There's soundadvice in your (shortened) letterMr Mayer. Although radio ama-teurs are (by the nature of ourhobby) aware of repair pitfalls, it'salways best to have a writtenagreement as to what's to happento your equipment when it needsrepairs.
Dear SirI was sufficiently annoyed withFebruary's Practical Wireless to put pento paper. I am only an occasional readerof Practical Wireless, just buying issueswhich contain something of particularinterest to me.
I have an interest in receivers and in oldEddystones in particular, so when I saw the 'receiving special' label and 'Eddystone receivers' with picturesof a 750 and a 6100, I was pleased to grab it off the newsagent's shelves just as they were closing.
At first I thought that somehow my magazine had the wrong contents, since there was nothing aboutEddystone receivers and very little about receivers or receiving at all. However, you did actually mentionthe Eddystones on the cover and there were a few badly written lines about the present day activities of thecompany, so I concluded that the contents must be correct.
Surely it is not unreasonable to expect the cover of a magazine to reflect the contents? February'sPractical Wireless has Eddystone receivers on the cover and contains zilch about Eddystone Receivers! Andwhat about the 'receiving special'? A very general article about building a receiver, also the v.l.f. converter,but nothing more than I imagine would appear in any other edition of PW.
Since it induced me, and probably many others to buy the magazine under false pretences, I shall bemuch more wary of PW in future.A. J. Richards GW4RYK, Montgomery, Powys
Dear SirRef: Code Free A LicencesI have recently been in contact with the RadioCommunications Agency regarding the above mat-ter, and having had the information sheetRA148(Rev1) sent to me, it would appear that thereis no longer a requirement for any marine radiooperator on m.f., h.f., and v.h.f. to be competent inthe sending and receiving of Morse code.
Having read this leaflet and had it explained tome in depth by the RA, why do we as amateurs needto take a Morse code test? Is it still to be the old syn-drome 'I had to learn so why can't you learn Morseto gain a licence to operate on the h.f. bands'?
In a reply to one of my many letters to the RA,they state that they are looking at a Morse exemp-tion licence, together with the RSGB.
If you feel you would like to gain an (A) licencewithout having to take a Morse code test why notmake your feelings heard in the correct place withthe Radio Communications Agency, AmateurLicence Section, Waterloo Bridge House, WaterlooRoad, London SE1 8BU to reach them before the 8thMarch 1993. If you are a member of the RSGB, writeto them at Potters Bar and tell them what you want.Someone, somewhere will eventually take notice.Thanks for a great magazine PWteam.Brian E. Mould G6FLXPortsmouth, Hampshire
Editor's reply: Following my comments andinvitation to readers in February's 1(eylines',we've had a large postbag on this subject bothfor and against the idea. We hope to publishextracts from as many as we can in the Aprilissue.
**** Star Letter ****
I have recentlystarted a Novice course and would like to see
Dear Sir
a section in Practical Wireless about the Novicecourse, or a
Novices corner. Also equipmentthat is covered by the Novice
licence, as most equipmentadvertised, or put on trial runs by
your many authors, aremainly for the people who have passed
the RAE. I have been reading Practical Wirelessfor four months
and find it lacking in the Novice criteria.
PS: If I do win in the competition cornerdraw, is there a
430MHz versionof the Alinco
DJ -180? I amconfident to pass
my NRAE in March!
Mubdi Choudbury,Manchester
Editor's reply: Thank you for your suggestions Mubdi,
and we're already working on the project. Watch this
space! Best of luck in the Alinco competition.- -
Editor's comment: Sorry that you weren't pleased by my cover choice Mr Richards. I felt thatas we had a 'receiving themed' issue I just could not let it pass without paying tribute to afamous and long established British manufacturer. However, readers have shown a great dealof interest in Eddystone equipment, and have asked for more. Ron Ham's 'Valve & Vintage'seems the best place to handle it, and I hope readers enjoy the feature when it appears.
14 Practical Wireless, March 1993
Send your letters to the editorial offices in Broadstone.They must be original, and not duplicated in any other
magazine. We reserve the right to edit or shorten any let-ter. The views expressed in letters are not necessarily
those of Practical Wireless. The Star Letter will receive avoucher worth £10 to spend on items from our Book, PCB
or other services offered by Practical Wireless. All other let-ters will receive a £5 voucher.
Dear SirI am hoping that this letter may be read by some of your major adver-tisers. I suggest they should make their pages interesting and do them-selves a favour in the process, by giving prices of all goods advertised.Some ignore such minor details, which suggests that 'if you have toask the price you can't afford it'. Others ask us to 'phone, implying thatthey dare not print such low prices - do they really expect us to makelots of expensive cross-country calls when we are probably just havinga look around to see what is on offer?
My other suggestion, on a similar subject, concerns the penny-wisepound-foolish behaviour of some big companies when asked for infor-mation. I recently decided it was time for a new mobile rig, and wroteto the big three importers for details and prices.
One sent me a great bundle of interesting information, one sent awell produced brochure, and one sent a single sheet of paper listingtheir whole range and telling me practically nothing. No prize forguessing which one I did not follow up!J. A. GaukrodgerOttery St MaryDevon
Editor's comment: I think the main reason for a some pricesbeing left out by advertisers, is that they fluctuate day-by-day.Another problem is that of the time delay between the adver-tiser's copy arriving in our office, and it being printed.However, to be fair, I hope at least one of our advertisers willwrite in reply to you Mr Gaukrodger.
Dear SirSoon after I started to dabble in a foreign language, I was given two marvellouspieces of advice which to my sorrow I ignored.
The first advice was that when learning a word in one language, it is almostas easy to learn it in three languages at the same time. If the languages soundfairly different for example, French, German and Spanish, you will be surprisedhow little confusion there will be.
The second advice was that the younger you are, the easier it is to learn.DO IT NOW!J. Wilshaw G3MPXWest WickhamKent
Editor's reply: I couldn't agree more, it's a pity I'm not younger!
Dear SirYou ask what valve projects we would like to see inPractical Wireless. Surely an absolute must is theall-time classic receiver, the EF50 t.r.f. RX. Publishedin Short Wave Magazine August 1946 and laterSWMJuIy 1947 by the late Jack Hum G5UM.
I was serving in the Royal Navy as a RadioMechanic at the time and built this RX as a 'rabbit',first as an OV1 and then later added the r.f. stage.When I got my license in 1948 it was this RX togeth-er with an EF50 crystal oscillator, 6V6 power amplifi-er and a VS1AA antenna that gave me contacts allover Europe with the odd Stateside contact for goodmeasure.
Using 9W input on 7MHz, c.w. of course!Although I had been building receivers since 1938,this little receiver out -performed anything I had everbuilt before. The original circuit showed choke out-put for headphones (which we all used in thosedays!).
The set would quite happily drive a small loud-speaker. The power supply was made from bits sal-vaged from a defunct domestic receiver. IncidentallyI still have the cuttings from Short Wave Magazinegiving details.Ron W. P. Wilson G3DSVExeter
Editor's comment: If you've got pho-tographs and details of your receiver Ron, Ifeel sure readers of 'Valve & Vintage' wouldlike to see them. Ron Ham is looking forwardto all your letters and memories dealing witholder equipment. So, get writing to him!
Dear SirGreetings from slightlywintry Wales, and beingmindful of how muchreading you have to do,and equally aware ofmy jerky hand -writingthese days, I'veresolved to borrow mywife's portable Imperialtypewriter a little moreoften, even though thenoise does intrude uponthe rustic serenity!
It isn't often I mixradio and religion(despite the etherialsimilarities) but Amen &Amen to your plea forold short wavereceivers. I have beenlooking around, asking,even advertising thesame plea for my vari-ous types, both this pastyear for the Noviciates.Most of the availablereceiver kits (evenGeorge Dobbs G3RJV'sSudden) are a bit toodaunting for beginners.
When the spiritmoves, I've a couplemore 'What A GoodIdea' items for you, but Ipromise to type themnext time!Wyn MainwaringGW8AWTLlandeiloDyfed
Editorial comment:Thanks for your let-ter Wyn. A good com-mercially madereceiver (anEddystone is a dreamfor some youngsters)is a great boost forthose starting off inthe hobby. Funnilyenough, owning suchsets often triggersoff the urge to trybuilding one! Yourtyping and shorterletters are muchappreciated, as theold Editorial eyesaren't what theyused to be!
New addresPractical Wireless and Short WaveMagazine have moved to ArrowsmithCourt, Station Approach, Broadstone,Dorset BH18 8PW.Full details on the contents page.
Practical Wireless, March 1993 15
New Hands Free Communication UnitsTechnotrend Ltd. of Farnborough, Hampshire, England, is offering Vox
operated Hands Free and semi Hands Free units for use with Private MobileRadio and Trunked Radio equipment.
These high quality units are compatible with most radio types withoutany need for modification to the radio. The easily installed electronics unitshave been designed to provide clarity of speech and suppression of outsidenoise. They are supplied with a versatile PTT (press to talk) switch and quali-ty microphone, which have been specifically designed for in -vehicle use.These competitively priced units have applications for professional userssuch as police, fire, ambulance and public utility vehicles. Distributors arealso sought.For further information, contact Technotrend Ltd., Unit B5, ArmstrongMall, Southwood Summit Centre,Farnborough GU14 ONR. Tel: (0252) 373242.
Send your news,photographs and
product informationto Sharon George at
our Broadstoneoffice.
Can You Help?
I have been given a 'Stephens -James Ltd.' Mk11multi -tuner for restoration. I have tried writing tothem at their Warrington address, but I believethey have ceased trading. Could you possibly askyour readers if anybody could help me with abrochure/circuit description. I will gladly refundany costs incurred. Graham Williams,'Alltwen', 44 Mayfield Drive, Buckley,Clwyd CH7 2PN.
Has anyone a handbook of the Taylor 45D2valve tester they could loan me, please? Or acopy of a booklet published during the war, enti-tled Morse In Seven Days by Vic Lewis? Willgladly reimburse costs. Douglas ByrneG3KPO, 52 West Hill Road, Ryde, Isle ofWight P033 1LN. Tel: (0983) 567665.
Has anyone any servicing instructions/circuitdiagrams for Clarkes Atlas, type A17 radio receiv-er. David Maxwell on (0484) 450982 day or(0484) 604546 evening.
I am trying to locate a copy of technical bulletinDTB4, published some years ago. Buy or photo-copy. All expenses would be met of course. MrJ. McGowan, 20 Keats Avenue, Romford,Essex RM3 7AR.
Dennis Godfrey GOKIU would like anyRAFARS members, or any past or present RAFpersonnel, to contact him on (0623) 659514,with a view to setting up regular meetings in theNottinghamshire area.
Wanted. Any information, circuit diagrams,etc., or ideas, where I may obtain these for aTotsuko TR2100M 2m s.s.b. transceiver, possiblyalso marketed as a Shimuzu. All costs willinglymet. Tom Burke G1LXU. Tel: (0472) 602335.
A hands -freecommunica-tions unit fromTechnotrend.
When contacting manufacturers ororganisations in 'Newsdesk', please
mention that you read it inPractical Wireless
Mains Power In Your Car?
Solar -PoweredPlant 1.71.t!rner
The new Maplin PlantTurner will support up to301bs weight and slowlyturn the plant during theday. This will help to pro-mote healthier, well -developed plants, and nomore lop -sided plants inthe shack.
The small solar panelis attached to a lm longflying lead, so the cellcan be positioned formaximum sunlight. Theturntable is 155mm indiameter and has araised edge. It is finishedin two-tone green plastic.
Other possible usesinclude displays in shopwindows or to create aneye-catching displayinside cabinets. Brightincandescent light willalso operate the plantturner.
Dimensions161x65mm. Orderdetails: BZ49D PlantTurner, £6.95 (inc. VAT).Maplin ElectronicsPO Box 3RayleighEssex SS6 8LR.Tel: (0702) 552911.
Until now you have had to rely on noisy and expensive generators for 240Vpower to operate mobile radio communications or computer systems. But now,help is at hand with the Merlin Pro Watt range of d.c. to a.c. inverters. These canbe either plugged into the cigarette lighter in your car, or wired direct to the bat-tery, the unit simply and silently converts 12V d.c. power to 240V a.c., allowingyou to benefit from mains power anywhere anytime.
Ideal for radio amateur enthusiasts, microwave ovens, TVs, videos, comput-ers, chargers, power tools, etc. This family of inverters consists of four models,the pocket -sized 125i and 200i, which have 125 and 200W continuous output withpeak power of 400W. The 800i is rated at 800W continuous and 2000 W peakpower. For really big demands, the 1500i delivers 1500W continuous and 3500Wpeak.
You needn't worry about running down your battery, all units feature a lowbattery protection circuit which shuts the unit down should the battery voltagedrop below 10.7V. They also feature overload and overheat protection.
If you have higher output requirements, Merlin have inverters with power out-puts of up to 22.5k\sinewave or pure soutput forms.
Prices are as fol125i £99.95; 200i £1800i £338; 1500i£517.75. All pricesexclude VAT andcarriage at cost.
For more infor-mation, please contact John Hortopon (0491)613027.
16 Practical Wireless, March 1993
the fourth major in-flight entertainmentdeal for BBC WorldService Television.Currently, CathayPacific, BritishAirways and RoyalBrunei also carry theservice.
BBC World ServiceTelevision is a whollyowned subsidiary ofthe BBC. It is entirelyself -funding. It is cur-rently available inEurope, Asia, Africa,the Middle East andCanada, and aims tobe global by the endof 1993. BBC WorldService news bul-letins are also carriedon NTV - Germany'sfirst 24 -hour newschannel launched inOctober.
BBC World ServiceTelevision
BBC World ServiceTelevision has recent-ly added a new highflying audience to itsmillions of viewers onthe ground for theNew Year.
As from 1 January1993, passengers onall internationalLufthansa flights havebeen able to keep up-to-date with the latestworld events withBBC World ServiceTelevision. The newswill be recorded liveoff air and dubbedinto German.Translations are mon-itored by BBC WorldService's GermanService.
The arrangement -made with CintecAirline News, basedin Frankfurt - marks
Co Fly ACornish Kite
As a keen radio amateur as well asa kite manufacturer, John GOJVR ofCornish Kites, enjoys lifting the anten-na by means of a kite. The local clubGB2GM Poldhu, often use their ownkite in conjunction with the perma-nent antenna systems at Poldhu(which is of course connected withMarconi's early transatlantic tests), forspecial events such as InternationalMarconi day. The men really enjoyplaying radio and kite -flying at thesame time, and of course the signalreports are greatly enhanced.
There are kite designs to suit dif-ferent weather conditions, from the
Sweet News From BulginThe concise and colourful RITEL range of controlknobs now provide perhaps the widest and mostcomprehensive range on the market.
With diameters from 8mm to 45mm, they'reavailable in four basic colours, and offer a choiceof push -fit or collet fixing to suit metric and imperi-al diameter shafts.
Ritel knobs are styled to match your product orproject, and while push -fits come in a selection ofmatt black or light grey, collet versions are sup-plied in light grey, dark grey, black or red.Metallised types are also available and the range isfurther enhanced by wing and arrow shaped typesfor versatility.
Customisation can be made by using the vastselection of snap -in caps, available in various pro-files and colours in a wide variety of markingoptions.
A full range of accessories, including dials, sta-tors, pointers and nut covers, complete this range.A. F. Bulgin & Co. PlcBypass RoadBarkingEssex IG11 OAZTel: 081-594 5588.
A personalisedCornish Kitefor a v.h.f.operator keento work DX.
John GOJVRgetting the'needle' into ajob!
gentlest breeze through to what peo-ple in Cornwall call 'bracing'. CornishKites have been manufacturing kitesfor 17 years and are now enjoying alot of interest both in the UK andabroad from radio amateurs wantingthe convenience of a personalised kitefor mobile or maritime mobile use.
All kites are hand -made inCornwall using 100% SpinnakerNylon, for strength and durabilitywithout much weight.
For further information, contactCornish Kites, The Workshop,Mullion, Cornwall TR12 7DN. Tel:(0326) 240144.
Radio Amateur ReliefExpeditions
In March 1991, a group of radio amateurs fromaround the country joined a team of volunteers to travelacross Europe to become part of a team of relief work-ers in Romania. Their help in providing communica-tions between eight projects - hospitals and orphanagesand a central store, and also a link back to the UK fromthe town of Turnu Severin in the Mehedinti area, great-ly contributed to the efficiency of the project.
The event made a lasting impression on some of theteam and when, in 1992, further projects were arrangedin the same area, together with some more interestedradio amateurs they returned, and not only providedradio communication, but also became involved in thepractical side of the work, in finding equipment, sup-plies and drugs for the rural medical centres whichwere being renovated and set up.
As the involvement in these projects became known,more requests for help began to come through, andafter a great deal of thought, it was decided to set up anorganisation called Radio Amateur Relief Expeditions(RARE), to properly organise and co-ordinate events.
Lead by Dave Davies GOKWY of Swansea and DonSunderland G6FHM of Shrewsbury and assisted by aretired senior army officer, it's hoped to achieve charitystatus and to create a database of radio amateurs whowish to help and/or take part in expeditions.
Some of the current projects include, finding specificitems requested by Turnu Severin Hospital in Romania.They've also had requests for radios to be used for hos-tels for the home -less street children in Bucharest; helpin setting up a kindergarten in Bucharest; and reliefwork in Yugoslavia.
The group need your help, and the under -privilegedand stricken people also need your help. Members notable to go on expeditions could play an essential part inprocuring equipment, etc., and fund raising. Ilt costsover £1000 to send a wagon to Romania).
The new group also need members who have skillsand experiences as well as being radio amateurs - med-ical, engineering, teaching, building, HGV drivers, etc.
If you feel you would like to join them, please con-tact Don Sunderland G6FHM, sending brief details ofyour experiences and skills and how you feel you couldhelp.
1 Allfield CottagesCondoverShrewsbury SY5 7APTel: (0743) 873815.
Practical Wireless, March 1993 17
New Headquarters For ITCThe IndependentTelevision Commissionhas signed a long-termlease on new headquar-ters in London. The ITCwill be moving in thesummer from theirlong-established pre-sent location oppositeHarrod's in BromptonRoad, which was alsothe location for theirpredecessors the ITAand IBA.
The new building issignificantly smaller
than the ITC's presentbuilding, and reflectsthe overall reduction inthe staffing levels of theCommission and of thenumber of staff based inLondon.
The new building at33 Foley Street, LondonW1, has been complete-ly refurbished and reno-vated by the developersand is now re -fitted tomeet the needs of the105 staff who will workthere. Interestingly, the
new building used to bethe headquarters ofWorldwide TelevisionNews, and it also had anearlier association withAN, the predecessor ofCentral Television.
Last December, a fur-ther 40 staff moved, orare in the process ofmoving to King WorthyCourt in Kings Worthy,Hampshire, mostly fromthe old IBA EngineeringHeadquarters atCrawley Court,
The Yeovil Club Project
Fig. 1: The Yeovil Club Chairman, Derek AlexanderG4GVM (left) and Charles Leitch G1XKS busilyworking on the final setting -up on their Yeoviltransceivers, watched over by (left to right) G3ICO,s.w.l. Brian, Yeovil Project designer Tim WalfordG3PCJ and G3GC, G4JBL, G7GDY and G3CQR.Photograph by B. F. Hillard.
Fig. 2: A close-up view of the completed Yeovil Club Project, providinga good idea of the compact, but uncomplicated nature of thetransceiver. A comprehensive 50 -page manual has been prepared, sothat other clubs may join in the project. Full details are available fromTim Walford G3PCJ. Photograph by B. F. Hillard.
Astronaut Becomes Honourary Member Of RSGB
Britain's first astronaut, Helen Sharman, has been made an honourary mem-ber of the Radio Society of Great Britain. The honour was bestowed on Helen onJanuary 11 because of her valuable work in interesting schoolchildren in spaceand radio communications during her flight in the Soviet space station Mir, dur-ing 1991. The presentation was made by the new RSGB President for 1993, PeterChadwick G3RZP.
The 3M (UK PLC) company haverecently enhanced their range of2mm board mount sockets andheaders.
Winchester. TheCrawley Court locationis now the headquartersof NationalTranscommunicationsLtd., the now -privatisedformer IBA EngineeringDivision.
Several more staffwill be relocated fromLondon during the firstsix months of 1993 andthe total number of ITCstaff, including its 12national and regionaloffices, is now 190.
Over the autumn and winter, 14 members ofthe Yeovil Amateur Radio Club have been
building a well specified 10W p.e.p. s.s.b.and c.w. transceiver for 3.5 and 14MHz,called 'The Yeovil'.
The project has consisted of explanato-ry talks on the theory, and the issuing of
kits of components for members tobuild at home. The projectwas then backed up bytest nights at the club,covering each of the threemain blocks of the receiverand two more for the trans-mitter.
The Yeovil receiver(which can be used on its own) is on
one 100 x 160mm p.c.b. with the transmitter ona second, similar p.c.b. The complete transceiver pro-ject have cost approximately £110, but spread overseveral months has eased the burden!
The complete rig consists of a bi-directional super -het with a 9MHz crystal filter with conventional orvaractor tuning. The transceiver also has a.g.c., c.w.filter, r.i.t., electronic transmit -receive switching, apush-pull f.e.t. final r.f. amplifier, low-pass filters,antenna matching bridge with semi break-in control,and sidetone for c.w.
Although designed for a 12V d.c. supply, up to40W p.e.p. can be obtained with higher voltage sup-plies. A comprehensive manual has been producedso that other clubs might like to try the project forthemselves. Full details can be obtained from: TimWalford G3PCJ, Upton Bridge Farm, LongSutton, Langport, Somerset TA10 9NJ.
3M United Kingdom ConnectorsThe 3M (UK plc) Company have recently enhanced its range of connectors, with the addi-
tion of a series of 2mm board -mounting sockets and headers.The 3M company claim that they offer the widest range of 2mm connectors offered by a
single manufacturer. Their series 15 includes right-angle and straight board -mount sockets,low profile, through -board bottom entry sockets, and pin strip headers.
The range of connectors are designed to save up to 38% of p.c.b. space, and 47% ofabove -board height compared to equivalent 0.1in grid industry -standard products. The con-nectors are end and side stackable to maximise the use of p.c.b. space, thereby helping toreduce costs.
The connectors are suitable for through -hole and surface mount applications. They incor-porate a glass -filled polyester or liquid -crystal polymer body (LCP). The LCP material; with-stands the higher temperatures associated with infra -red and vapour soldering techniques.
For further details contact: P. Lindsay Powell at 3M United Kingdom plc,Market Place, Bracknell, Berkshire RG12 1JU. Tel: (0344) 858509.
18 Practical Wireless, March 1993
Please send in all of
your 'Club News'items to Sharon
George at the neweditorial offices in
Broadstone.
Bedfordshire
Shefford & DARS. Thursdays,8pm. Church Hall, Ampthill Road,Shefford, Bedfordshire. February 25 -Shacklog 3, the new version by AlanJubb G3PMR, March 11 - Recoveryof the Olympus Satellite. PaulG1GSN on (0462) 700618.
Berkshire
Newbury & DARS. Wednesdays,7.30pm. Bucklebury Memorial Hall.February 24 - Mini Lecture night.(0635) 46241.
Reading & DARC. 2nd & 4thThursdays, 8pm. The WoodleyPavilion, Woodford Park, HaddonDrive, Woodley, Reading. February11 - The Computer In Amateur Radioby John Linford G3WGV, 20th - HelpWith Girl Guides Thinking Day byGOPUB, 25th - Digital Modes &Equipment, ICS Electronics Ltd.,March 11 - Club Quiz vs MaidenheadClub. Nick Challacombe GOLGG on(0734) 722489.
Buckinghamshire
Aylesbury Vale RS. 1st & 3rdWednesdays, 8pm. Village Hall atHardwick. February 17 - TheOscilloscope & Its Uses by N.Pritchard G8AYM, March 3 - RSGBVideo evening. Marlyn G4XZJ on(0296) 81097.
Cheshire
Mid -Cheshire ARS. CotebrookVillage Hall, Cotebrook, nr.Northwich, Cheshire. February 24 -Pancake night, March 3 - on airnight, 10th - talk on CW by DaveG4XUV. Mike Baguley G7LQD on(0606) 331210.
Stockport RS. 2nd & 4thWednesdays, 7.45pm. Room 14,Dialstone Centre, Lisburne Lane,Offerton, Stockport, Cheshire. March10 - Amateur TV by R. Dexter GOITP.Jim France G3KAF on 061-439 4952.
Clwyd
Wrexham ARS. MaesgwynCommunity Centre, Maesgwyn Road,Wrexham. February 16 - Video night- Amateur Television, March 2 - talk.Ian Wright GW1MVL on (0978)845858.
Cornwall
Cornish RAC. Village Hall,Perranwell Station, Perranwell, nr.Truro, 7.30pm. February 15 -Computer Section, March 4 - PowerSupplies by Bert G3VVVK, 9th -Activities night. Geoff Bate on (0209)820836.
Derbyshire
Buxton Radio Amateurs. LeeWood Hotel, Buxton, 8pm. February23 - Video night, March 9 - Fox Huntsexplained. Derek Carson G41H0 on(0298) 25506.
Derby & DARS. Wednesdays,7.30pm. 119 Green Lane, Derby.February 24 - Packet Radio by EdGOINA, the sysop of the GB7BAD &GB7NOT bulletin boards, March 3 -Junk Sale. Richard Buckby G3VGWon (0773) 852475.
Devon
Appledore & DARC (Devon). 3rdMondays, 7.30pm. AppledoreFootball Clubroom. February 15 -Morse class & construction demo &talk by Bob Short G3GNR. RegLyddon G4ETJ OTHR on (0237)
477301.
Torbay ARS. Fridays, 7.30pm.ECC Social Club, Highweek, NewtonAbbot. February 19 - AGM. AndyStafford G4VPM on (0803) 329055.
Dorset
South Dorset RS. 1st Tuesdays,7.30pm. Wessex Lounge ofWeymouth Football Club. March 2 -Bring, Buy & Barter. Mike LenziG7HNY on (0305) 773860.
Down
Bangor & DARS. 1st Fridays,8pm. Winston Hotel, Queens Parade,Bangor, Co. Down. March 5 -Medical Electronics by Jim BrownGI4BXB. Des Buckley GI3HCP on(0247) 460251.
Dumfries & Galloway
Wigtownshire ARC. Thursdays,7.30pm. Community Education Office,Stranraer Academy. Ellis GastonGMOHPK on (0581) 2202.
East Sussex
Hastings Electronics & RC. 3rdWednesdays, 7.45pm. West HillCommunity Centre, Croft Road, West
Hill, Hastings. February 17 - WeatherRecording by G4ITM, AGM. G3YYFon (0424)830454.
Southdown ARS. 1st Mondays,7.30pm. Main hall of the ChaseleyHome for Disabled Ex -Servicemen,South Cliff, Eastbourne. Wednesdays(Morse) & Fridays (Novice & RAE),7.30pm at the clubrooms, HailshamLeisure Centre, Vicarage Road,Hailsham. February 1 - PMRProblems by Keith G8HGM. JohnVaughan G3DQY on (0323) 485704.
Essex
Braintree & DARS. 1st & 3rdMondays, 8pm. Community Centre,Victoria Street, Braintree. February15 - PMR Conversion - practicalG3PEN/GODEC. M. J. Andrews on
(0376) 327431.
Chelmsford ARS. 1st Tuesdays,7.30pm. Marconi College, ArbourLane, Chelmsford, Essex. February21 - East Coast AR & C Rally,Clacton -on -Sea, 27th - RainhamRadio Rally, Gillingham, Kent, March2 - History Of Radar by Stan Woods.Roy & Ela Martyr G3PMX & G6HKMon (0245) 360545.
Greater London
Acton, Brentford & ChiswickARC. 3rd Tuesdays, 7.30pm. ChiswickTown Hall, Heathfield Terrace,London W4. February 16 - WAB byGOHHP. Colm Mulvany GOJRY on081-749 9972.
Clifton ARS . 'Earl of Derby'Public House, Dennetts Road, NewCross, London SE14. February 19 - HFevening, March 5 - Film evening.Keith Lewis on 081-859 7630.
Edgware & DRS. WatlingCommunity Centre, 145 Orange HillRoad, Burnt Oak, 8pm. February 11 -Model Rockets by Bob Goss G4CQF,25th - Morse Training evening,March 11 - Bring & Show evening.Howard Drury G4HMD on (0923)822776.
Silverthorn RC. Fridays, 7.30pm.The Chingford Community & AdultEducation Centre, Friday Hill House,Simmons Lane, Chingford, London E46JH. February 19 - Preparationevening for Thinking Day on the Airevent, 20th - Thinking Day on Airevent in association with the Guide& Brownie Troops that meet inChingford. Andrew MowbrayGOLWS on 081-529 4489 between5.30 & 6.30pm weekdays only.
Southgate ARC. Winchmore HillCricket Club Pavilion, Firs Lane,Winchmore Hill, London N21.February 11 - Multi -mode Action onthe Air, 25th - Inter -Club DartsMatch, March 11 - Rig Checkevening by Donald G4DFB. BrianShelton GOMEE on 081-3602453.
Gwynedd
Dragon ARC. 1st & 3rd Mondays,7.30pm. Four Crosses Hotel, MenaiBridge. February 15 - A Rough GuideTo QRP by Stewart Rolfe GWOETF,March 1 - St. David's Day RadioEisteddfod - look out for list of corn-petetive events. Tony Rees GWOFMOon (0248) 600963.
Hampshire
Basingstoke ARC. 1st Mondays,7.30pm. Forest Ring CommunityCentre, Sycamore Way, Winklebury,Basingstoke. February 28 - 2mDirection Finding Competition 0S185Fox: Dave G7JZU. (0256) 25517.
Horndean & DARC. 1stThursdays, 7.30pm. HorndeanCommunity School, Barton Cross (offCatherington Lane), Horndean,Hants. March 4 - Control &Communications/First Action FirstAid - Hampshire Ambulance Service.Stuart Swain GOFYX on (0705) 472846.
Itchen Valley RC. 2nd & 4thFridays, 7.30pm. Scout Hut, BrickfieldLane, Chandlers Ford. February 12 -Photography Update includes Close-ups & restoring black & white printsby Bob Thomas, 26th - open meeting.Maurice Cheeseman G1IPQ on(0703) 736784.
Hereford & Worcester
Bromsgrove & DARC. Fridays.Avoncroft Arts Centre, SouthBromsgrove, Worcester. February 12- Photography. Joe Poole G3MRC on(0562) 710010.
Hertfordshire
Cheshunt & DARC. Wednesdays,8pm. Church Room, Church Lane,Wormley, nr. Cheshunt, Herts.February 17 - natter night, 24th -Amateur TV Repeater talk & demo byAdrian GOOJY, March 3 - MembersForum, 10th - Quiz night hosted byAlvin G1VXD. Roger Frisby G4OAAon (0992) 464795.
Decorum AR & TS. 1st (informal)& 3rd (formal) Tuesdays, 8pm. TheHeath Park, Cotterells, HemelHempstead. February 16 - AerialDesign part 2 by Mike GoodwinGONJI. Dennis Boast G1AKX on(0442) 259620.
Hoddesdon RC. AlternateThursdays, 8pm. Conservative Club,Rye Road, Hoddesdon, Herts. March4 - natter night. Roy G4UNL on 081-804 5643.
Stevenage & DARS. GroundFloor Rear Suite, Sitec Building,Ridgemond Park, 7.30pm. February16 - Practical night - On Air Practice& Procedures, 23rd - The AmericanExperience Take 2 by Tony GOOVO.Pete Daly GOGTE on (0438) 724991.
Practical Wireless, March 1993 19
Humberside
Bridlington & DARS . AlternateThursdays, 7.30pm. Combined CadetBuilding at Bridlington Upper School,Bridlington. February 19 - ComputerProgramming by Keith Goodyear.Norman Bedford G4NJP on (0262)673635.
Kent
Bredhurst T&RS. Thursdays,8.15pm. Parkwood CommunityAssociation, Parkwood Green,Rainham, Kent. Martin PearsonG7JBO on (0634) 365980.
Sevenoaks & DARS. January 18 -Semiconductor Manufacture byEddie Brownlow. The Secretary, c/oSevenoaks District Council, CouncilOffices, Argyle Road, Sevenoaks,Kent TN13 1HG.
Lancashire
Hesketh ARC. Every otherTuesday. Birkdale, Southport.February 16 - GRP on the air, March3 - Bring & Buy. Bernie G7DEM on(0704) 63344.
Lincolnshire
Grantham RC. 1st & 3rdTuesdays, 8pm. Kontak Sports &Social Club, Barrowby Road,Grantham. February 16 - ATU's byJohn G3VSX, March 2 - FirePrevention in the Shack. John KirtonG8WWJ on (0476) 65743.
Lincoln Short Wave Club.Wednesdays, 7.30pm. City EngineersClub, Central Depot, WatersideSouth, Lincoln. February 17 - SurplusEquipment Auction. John RiddochG1TSL on (0522) 750757.
Spalding & DARS. Fridays, 8pm.The Riverside Centre, The Old FireStation, Double Street, Spalding,Lincolnshire. February 12 -Communications & Motor Sport byG7HNM. David Johnson on (0778)425367 (6-7pm).
Merseyside
Liverpool & DARS. Tuesdays,8pm. Churchill Club, Church Road,Wavertree, Liverpool. February 16 -Weather Satellites by G3PDC, 23rd -Surplus Sale, March 2 - Quiz, 9th -Activity night. Ian Mant G4WWX on051-722 1178.
Wirral & DARC. Irby CricketClub, Mill Hill Road, Irby, Wirral, 8pm.January 20 - D&W, Black Horse,Lower Heswell, 27th - SurplusEquipment Sale. Paul RobinsonGOJZP on 051-648 5892.
Middlesex
Echelford ARS. Community Hall,St. Martin's Court, Kinston Crescent,
Ashford, Middlesex, 7.30pm February11 - Intruder Watch by J. CleeveG3JVC, 25th - Construction Contestevening - bring your latest project. P.Townshend G6PMT on (0344) 843472.
Norfolk
Dereham ARC. 2nd Thursdays,8pm. St. Johns Ambulance Hall,Yaxham Road, Dereham. March 11 -Strange Noise on HF explained.Mark Taylor GOLGJ on (0362) 691099.
Norfolk ARC. Wednesdays,7.30pm. The Norfolk Dumpling, TheLivestock Market, Harford, Norwich.February 17 - Science For All byArnold Tomalin G3PTB, 24th - infor-mal & night on the air. Jack SimpsonG3NJQ on (0603) 747992.
Northants
Kettering ARS. Tuesdays,7.30pm. Electricity Sports & SocialClub, Eksdale Street, Kettering.February 23 - Gas Distribution &Radio Links by a speaker from BritishGas. Len GORDV (but QTHR as
G7EHM) on (0536) 514544.
Nottinghamshire
Mansfield ARS. Polish CatholicClub, off Windmill Lane, WoodhouseRoad, Mansfield. March 4 - TheBritish Repeater Network by G8SSL.Mary GONZA on (0623) 755288.
Nottingham ARC. Thursdays, 7.30pm.Sherwood Community Centre,Mansfield Road, Nottingham.February 11 - Generating your ownPower, 18th - construction/activity/prep for TDOA, 25th - TheLundy Island Dxpedition by LionelG5LP, March 4 - Forum/FoxuntForum, 11th - Around the World In 43Days by G4MHB. Ian Miller G4JAEon (0602) 232604.
South Notts ARC. HighbankCommunity Centre, FarnboroughRoad, Clifton Estate, Nottingham, orFairham Community College,Farnborough Road, Clifton Estate.February 12 - construction (FairhamCollege), 19th - Talk-in/The SecretWar by Henry Balen, 26th - on air,March 5 - Talk -in (S221/ Open Forum.Ray G7ENK on (0602) 841940.
Scotland
Aberdeen ARS. Fridays, 7.30pm.35 Thistle Lane, Aberdeen. February12 - The Great Morse Debate, 19th -Electrotherapy by Bill GM3FRI, 26th -How I Got Started In Amateur Radioby various speakers, March 5 - JunkSale. John GM1TDU on (0224)706619.
Dundee ARC. Tuesdays, 7pm.College of Further Education,Graham Street, Dundee. February 16- construction night, 23rd - A holidayIn South Africa by Sam Hall
GM2AOL. George Millar GM4FSB, 30Albert Crescent, Newport -on -Tay,Fife DD6
Wigtownshire ARC. Thursdays,RAE & Morse, chats, etc. StranraerAcademy, 7.30pm to 10pm. EllisGaston GMOHPK on (0776) 7215
evenings or (0294) 217979 day.
Somerset
Taunton & DARC. 1st & 3rdFridays, 7.30pm. The Basement,County Hall, The Crescent, Taunton.Other Fridays informally for stationoperation, Morse code class, natter.February 19 - Visit to SomersetCounty Archives. Mr Lindsay -SmithG3WNI on (0823) 680778.
Yeovil ARC. Thursdays. RedCross HG, Grove Avenue, Yeovil,Somerset. February 11 - VintageRadio by G7LNJ, 18th - Club project20/80m Transceiver Theory byG3PCJ, 25th - Don't Be Afraid Of CWby G3GC, March 4 - Club project20/80M Transceiver Final Testing byG3PCJ. Cedric White G4JBL on(0258) 73845.
South Glamorgan
Barry ARS. Alternate Thursdays.Old College Inn. February 21 - BarryMobile Radio Rally, Barry LeisureCentre. Ann MacKay GWOSQT,QTHR.
South Yorkshire
Barnsley & DARC. Mondays.Radio club room & shack, at the rearof the Darton Hotel, Station Road,Darton, Barnsley. March 1 - on theair night, 8th - proposed talk. ErnieG4LUE on (0226) 716339.
Suffolk
Felixstowe & DARS. March 1 -
radio -related video evening atOrwell Park School, Nacton,Ipswich. Paul Whiting G4YQC on(0394) 273507.
Sudbury & DARC. 1st Tuesdays,8pm. Five Bells Inn, Great Cornard,Sudbury, Suffolk. February 14 -Cambridge Rally, 21st - East CoastAmateur Radio & Computer Rally,March 2 - SAnDRA Club night at theFive Bells, Great Cornard, natter 'n'noggin night, with a raffle. ColinMuddimer GOPAO on (0787) 77004.
Surrey
Surrey RCC. Terra Nova' TheWaldrons, Waddon, Croyden,Surrey. February 15 - natter night,March 1 - Surplus Sale. Berni G8TBon 081-660 7517.
Sutton & Cheam RS. 3rdThursdays, 7.30pm. Sutton UnitedFootball Club, The Borough SportsGround, Gander Green Lane, Sutton,
Surrey. Natter nights - 1stThursdays. February 18 - constructional contest, March 4 - natternight, 6th - Annual Dinner at theSutton United Football Club. JohnPuttock GOBVVV, 53 AlexandraAvenue, Sutton SM1 2PA.
The Kingston & DARS. 3rdWednesdays, 8pm. Alfriston, 3Berrylands Road, Surrey KT5 8RB.February 17 - SWR Bridges, a.t.u.s,etc., by G. Cripps G3DWW. RayFuller on 081-398 1128.
Wimbledon & DARS. 2nd & lastFridays. St. Andrews Church Hall,Herbert Road, Wimbledon SW19.February 12 - Vertical antennaadjustment, 26th - The History OfCameras by Chris GOKEB. Chris FrostGOKEB on 081-397 0427.
Warwickshire
Stratford -Upon -Avon & DRS. 2nd& 4th Mondays, 7.30pm. Home GuardClub, Main Road, Tiddington,Stratford -Upon -Avon, Warwickshire.February 22 - Test Equipmentevening, Terry Downing G3MXH,March 8 - RF Problems AssociatedWith Motor Vehicles by TomDobedoe & Mike Nielsen. AlanBeasley GOCXJ on (0608) 82495.
West Yorkshire
Halifax & DARS. 1st & 3rdTuesdays, 7.30pm. Running ManPublic House, Pellon Lane, Halifax.February 16 - Junk Sale - QueensRoad Neighbourhood Centre. DavidMoss GOMM on (0422) 202306.
Keighley ARS. The IngrowCricket Club, Ingrow, Keighley, 8pmFebruary 11 - New High -SpeedNicad Charging, short talk by G3RXS,18th - night on the air GXOKRSGX7KRC, 25th - Visit to West YorksFire HQ, March 4 - natter night, 11th -The Sky, The Beauty & The Wonderby Mr Dougherty. Kathy ConlonGORLO on (0274) 496222.
Wiltshire
Trowbridge & DARC. 1st & 3rdWednesdays, 8pm. SouthwickVillage Hall, 8pm. March 3 - DirectConversion RX by GOBBL. Ian GOGRI
on (0225) 864698.
20 Practical Wireless, March 1993
Irecently had to replace my antique andunreliable oscilloscope. I sourced a suitablesurplus oscilloscope, but nearly died of shockwhen told the price.
What happened to the surplus equipment pricesof my youth? So, when PW gave me the MX -9000to review, the first thing to enter my mind was itscost, knowing that the answer might invoke a sharpintake of breath.
The people at SAJE Electronics boastunashamedly, that the price of £399 plus VAT,represents excellent value for money. So, armedwith my catalogues I set about checking their claim.
When the instrument arrived, I found an auto -ranging digital multimeter, a 100MHz countertimer, a 0-2MHz function generator and a three railpower supply, at an astounding total price. Afterchecking the specifications, of the items of testequipment I'd sourced, against the MX -9000, Ibecame convinced, that SAJE were right in theirclaim.
Multimeter Important
The multimeter, to my mind, is the mostimportant item of test gear in any electronicconstructor's workshop. The digital multimeter(d.m.m.) supplied with the MX -9000 is a verypractical instrument. It's an auto -ranging type,leaving both hands free to hold the test prods inplace.
A second feature is a memo button that storesone reading. This reading is used as a reference forfollowing readings, giving a difference -between -two -values reading capability. The controls of themeter are very easy to operate, and the three andhalf digit l.c.d. display has reasonable visibility atmost viewing angles.
Operating the meter is very straightforward.Select the units to be measured via the rotaryswitch, and plug the test prod in the appropriatesockets, and let the meter take care of the rangeneeded. Changing from a.c. to d.c., or high/lowohms requires only a flick of a switch.
The meter has overload protection (for a limitedtime), with the exception of the high current range.The low current ranges are protected by a fuse. Nostandard meter was available to check the accuracyof the unit, but it it compared favourably with myworks d.v.m.
I found the two prod type test leads, supplied asstandard, adequate. But my personal preference hasalways been for the option of at least one,preferably both, prods replaceable by an insulatedcrocodile clip.
Frequency Counters
Being a v.h.f. radio enthusiast can cloud yourjudgment at times, particularly when it comes todigital frequency counters. Because of this, I foundmyself wondering why only 100MHz maximum?
The obvious answer is that the MX -9000 isdesigned and built to a given budget. After talkingwith a few electronics (only) enthusiast friends, Iwas convinced that Maxcom had found a goodcompromise.
The timer section of the MX -9000 counter willobviously come into its own when working ondigital circuitry. Especially if you have only a verybasic oscilloscope. For people like myself, a pre -scaler would make the MX -9000 counter timer intoan instrument that would work on digital and v.h.fanalogue circuits.
On test, the sensitivity of the counter was morethan adequate and certainly better than themanufacturer's specification. After only a 15 -minute warm-up period, the accuracy of the counterwhen checked against a workshop standard waswithin ±200Hz at 10MHz and 100MHz.
The only problem I had with the counter sectionwas reading the display. I found this to be too dimfor stronger workshop lighting. The display is, atbest, a strain on the eyes and for long periods couldgive headaches.
The input (Hi impedance) of the counter is via aBNC socket. It may be linked to read the frequencyof the function generator.
A nice touch, is a switchable -10dB pad givingthe counter a degree of input protection. A coaxiallead with BNC and crocodile connectors isprovided for use with the counter or functiongenerator.
Function Generators
Working in a test house, as I do, makes youappreciate the usefulness of function generators.These are normally used as a means of providing acomplex waveform to stimulate systems or circuitsunder test. The function generator provided in the
Richard Ayley
G6AKG, looks at
the One Box -
Four testInstrumentsystem from
Maxcom.
Maxcom MX -9000Practical Wireless, March 1993 21
Fig. 1: Thepower supplysection of theMX9000,showing theopen method ofconstruction.
22
MX -9000 would be a very useful addition to ourrange of test equipment.
The generator in the review model, covers0.02Hz to 2MHz in seven ranges and provides sine,triangle, skewed sine, ramp, pulsed and squarewaveforms. The latter at t.t.l. level if required.
Both 50 and 6000 impedance outputs areprovided, with a 2V maximum output under loadand more than 3V at the t.t.l. output. The symmetryand d.c. offset of each of the waveforms can bevaried by two separate front panel controls.
Useful Feature
A very useful feature of the generator, is that anexternal ramp voltage may be applied to sweep thefrequency of the generator. One use of this featurepopped into mind immediately, and that is to use itin conjunction with a 'scope to view the response ofaudio filters or even receiver If. filters. That's theradio amateur speaking again, sorry!
Also provided is an internal ramp generatorwhich will sweep the frequency of the functiongenerator, either logarithmically or linearly over avariable time setting between 20ms and 2s. Thelevel of harmonics for the sine wave output werechecked using an audio spectrum analyser, andseemed to be in the order of 5 to 10dBs lower thanthose quoted.
The feature previously mentioned of enablingthe counter to be connected internally to the outputof the function generator is helpful. This is becausethe calibration of the frequency setting dial was lessthan accurate.
Power Supply
Now it's time to look at the power supplyfacility. If there ever was such an over -pricedsection of the market, the bench power supplysection must be it.
To my way of thinking, the average bench powersupply can be put together by just about anyelectronics hobbyist worth his salt. There are manygood and simple designs available, which makesthe price asked for some of the lower specificationcommercial units scandalous. Because of this, thepower supply section of the MX -9000 alone canmake the instrument seem good value for money.
The MX -9000 p.s.0 provides two fixed supplyrails, one of 5V at 2A and the other 15V at 1 A anda third rail rated 0-50V, 500mA. This rail is fittedwith a current trip control which is very frustratingto use and to my mind needs changing to a currentlimit.
When the current trip activates, it is necessary toremove the a.c. supply from the MX -9000 to reset
it. Which means that apart from upsetting the longterm stability of the counter and the functiongenerator, it also puts undue wear on the powerswitch.
The third rail is metered with its own three andhalf digital meter, both current and voltage. Theaccuracy of this display when checked against thed.m.m. section of the MX -9000 showed it to be nomore than a rough indication. The rather arbitraryreading given on the current range on the meter,combined with the abrupt nature of the current trip,makes it almost impossible to set the currentcontrol with any accuracy.
Either of the two fixed supplies may be used inconjunction with the 0-50V supply to provide eithera ±5V or ±15V supply. With the obviousrestrictions set by the 0-50V supply.
When overloaded, each of the fixed rails have acurrent 'fold -back' protecting action. A warning isgiven though, not to leave it overloaded for anextended period.
I felt that speaking overall, the p.s.u. is justbelow the standard of the other parts. This is shame,because with little extra work in this area, I felt amuch nicer instrument would result.
Construction
The construction of the MX -9000 with its manywell located front panel controls, can't help beinglarge. Consequently it's a rather bulky instrumentand not easily used outside the lab or workshop.This is a price you pay for having everything in onebox. The unit is very convenient, but it may losesome of its versatility and compactness.
After that critisism, I have to say that the MX -9000 is well laid out, both internally and the frontpanel. To its credit, there are no fancy componentsused in the construction.
The p.c.b.s are all well made and internalconnections are via plugs and sockets, making theremoval of internal components for repair veryeasy. The casing and its internals are made of platedsteel, very substantial but rather heavy.
Service information is available from SAJEElectronic. This is one thing colleges and schoolswill, I'm sure, be glad of, as many carry out servicework on -site. It also means that you could modifythe awful current control on the p.s.u. Once thewarranty has lapsed of course.
Elegant Equipment
The MX -9000 is an elegant item of equipment.The front panel, made of a light grey mouldedplastics material, complements the outer two-partwrap -over case, finished in a textured beige paint.
The case had a very sharp back edge, which Ifound to my cost. I also felt the fold -down plasticsfront feet could be improved. In testing, I nudgedthe instrument and it crashed down, making mejump. On closer inspection, it appeared that the legsare not designed to be securely locked into place.
Operating Manual
The operating manual is fairly comprehensive,with a front panel diagram listing all the controlsand their function. Each section of the instrumenthas its own area of the manual describing theoperation.
However, I think that the manual was translatedinto English abroad. Or whoever wrote it, wasn'tusing his (or her) mother tongue! The manual doeslack clarity in some places, leaving you feeling that,you know what they mean (sort of), but you have totry it, just to make sure.
Practical Wireless, March 1993
Gate timeaccuracylime base
Sensitivity
Input impedanceInput level
In spite of this, considering the complexity ofthe MX -9000, the manual is not bad. And there ismuch to be said for the hands-on approach to learnhow to 'drive' equipment.
Final Thoughts
Overall, I think the MX -9000 is a very usefulpiece of test gear and will appeal more to theaverage electronics enthusiast than the radioamateur. In terms of value for money, it's a verydesirable item to anyone with a limited budget.
Manufacturer's Specifications
Perhaps SAJE might like to consider an systemaimed at the r.f. enthusiast. Say a fixed +12V/2Asupply with a simple r.f./a.f. signal generator and1GHz counter, plus a IOW h.f./v.h.f. power meterwith built in 'sniffer'. Then finish the whole lot ofwith a basic f.m. modulation meter.
Budget versions of all these instruments havebeen available for some time, all it needs issomeone to glue them together with a bit offorethought. Who knows, for £399, SAJE couldhave another winner.
Well I can dream, can't I?
Digital Multimeter31/2 digit large liquid crystal display (I.c.d.) with value hold, and relative measurement facilities.Basic measurementsVoltage a.c./ d.c. 750V maxCurrent a.c./ d.c. 10A maxResistance 2MS2 max
Voltage autoranging ( a.c./ d.c.) 10MS2 impedance.DC - 200mV, 2/20/200V, 1kV ±0.8% (+2 digits) max.AC - 2/20/200/750V ± 1.5% (+5digits) max.
Overload protection 1100V d.c. or a.c. peak for 60 seconds.
Current ( a.c./ d.c.)200mA ±1%( d.c.) ±1.5%( a.c.) (+5 digits)
Overload protection 400mA max (60s fused)10A ±1.5%( d.c.) ±2%( a.c.) (+5 digits)
Overload protection 13A max (40s un-fused)
Resistance Autoranging200SY/2k/20k/2001(Q 2MS2Accuracy ±0.8% (+4 digits)Overload protection 350V( a.c.) or 500V( d.c.)
Power Supply SectionOutput 1
Voltage 0-50VCurrent 0-500mARipple 1mV max.Load regulation 0.01%+5mVLine regulation 0.01%+5mVCurrent limit 500mA
adjustableDisplay Uses d.m.m.
Volts/Amps
Function GeneratorRange
DistortionOutput impedanceOutput levelOutput attenuatorInternal sweep
Sweep widthExternal sweepInput
Output 25V fixed2A2mV max.40mV30mV3AFold backOn I.e.d.
Output 315V fixed1A2mV max.35mV30mV2AFold backOn I.e.d.
PW
Section0.2Hz - 2MHz in seven 100:1 frequency ranges, with a 10:1(adjustable)mark -space ratio. Sine, Squewed sine, Square, Triangular, Ramp and Pulseoutput waveforms +t.t.l. level squarewaveless than 1% @ 100kHz5052 (±10%) and 6000(±10%) to 100kHz.2-20V p -p no-load-20dBs20ms-2s adjustableLinear or logarithmicMore than 100:1
0-10V ( d.c.) or ±20V ( a.c.)
Frequency Counter Section1Hz-100MHz eight digitsResolution ' 0.1/1/10/100Hz
depends on range in use.10/1s, 100/10ms±1HZ±ldigit±Time bas error10MHz clock5p.p.m (0-40°C) 5p.p.m. per year15mV (1kHz- 60MHz)30mV (60-100MHz)1M0./100pFa.c./ d.c. 15V r.m.s. direct150V r.m.s. with attenuator switched in
Our thanks go toSAJE, for the loan ofthe review model.They can supply theMX -9000 for £399plus VAT and carriagefrom their address at:117 Lovell Road,Cambridge CB4 2QW.Tel: (0223) 425440.FAX: (0223) 424711.
Fig. 2: Looking behindthe front panel, themultimeter section onthe left of thephotograph and thep.s.u. meter on theright. The p.c.b. in themiddle is the digitalcounter module, whichis separated from thefunction generatorbelow, by a metalscreening box.
Practical Wireless, March 1993 23
W AT kN,
o
W.
vGOOD ID A
Radio amateurs are always full of bright ideas! So, this month G3JDK fromRotherham and G40YX from Ludlow describe their ideas for a storage
system and a simple power supply.
Fig. 1: Fixing the coffee jar lids.
Fig. 2:The jar system in use.
Coffee Break StorageI like building and repairing all manner of electronicsthings. And like many readers, I have limited space to do itin. This is almost bearable when actually working on theequipment, a desk makes a suitable work area. Buteventually every available flat surface is covered withuseless, but absolutely indispensable items.
Every Rally
After nearly every rally, I return home laden with small,hard -to -get items for repairs and modifications that I intendcarrying out. But where to put them in the meantime?
Most constructors face problems when it comes tostorage of components. More especially if these componentsare small and fiddley. In the past, many partial solutions tothe problem have been tried, including polythene self -sealbags, pillboxes and folded envelopes.
Ideal Solution
All these methods have, for various reasons, beendiscarded. Cost, availability, and sheer cussedness in hidingsmall components, in that order. But now I've discoveredthe ideal solution.
My ideal answer to this problem, is the standard coffeejar. They come in a variety of sizes, have substantial screw -on lids and would only be thrown away otherwise.
If the jars are to contain only lightweight components,then a single hole in the middle of the lid is all that isneeded. For heavier items, two holes would be better. UsingNo.8 woodscrews, fix the lids to the underside of aconvenient shelf as shown in Fig. 1.
If the number of jars is more than can fit in a single row,then the most used items should be stored at the front. Andtake care to stagger the rows of jars, to allow you to see allthe jars easily.
The photograph of Fig. 2, shows my work bench. Thisshould give you a better idea of how it all works, thecontents of each jar to be seen with minimum fuss.
Silver-plated
When stored, silver-plated components, such as airspaced transmitter coils and tuning capacitors, sometimesturn black from atmospheric sulphur compounds. Myanswer to this problem is to drop an old-fashioned camphormothball into the jar, along with the silver-plated items.
The small white object shown in Fig. 3 is the mothball,and the addition of one to each jar containing silver-plateditems should keep them sparkling clean for a long time.
Fig. 3: The small white object is a mothball (see text).
24
H. N. Kirk G3JDK, Rotherham, Yorks
Practical Wireless, March 1993
Shopping List
Simple Variable Power Supply
There is nothing in electronicsthat works without a powersupply of some sort or other. Soit's no wonder that powersupplies are one of the mostdesigned and built items.
This is my fixed, butvariable, power supplydeveloped for ease of design andbuilding. The p.s.u. is capable ofsupplying almost 5A with theright components.
The right components are asuitable 5A transformer Tl,diodes D1-4, and a heatsink thatcan dissipate the excess powerdeveloped in this type Of p.s.u.I've limited the current to justover 3A with a fuse, as I'vefound that, this in practice isabout the maximum current thatcan be drawn before the systembecomes too hot.
Simple Circuit
The full circuit diagram isshown in Fig. 1, and as you cansee, it really is a simple circuit.The integrated circuit IC1, hasall the active p.s.u. controlcircuitry on board.
The regulator i.c. has a 1.2Voutput, when the junction of RIand R2 is taken to the OV line.With a little bit of mathematicsthe output can be designed to bealmost any value between 1.2Vand the regulator's limit of 35V.
Because 1.2V is acrossresistor R2, 4.5mA must beflowing through it (1.2V/27052).This 4.5mA (plus a smallamount that IC1 needs to workproperly) is also flowingthrough R 1. This current flowholds the `Ady pin of IC1 at avoltage above the OV line.
As the current required byIC1 is quite small, I shall ignoreit for this circuit. So assumingonly 4.5mA is flowing throughRI, a voltage of 12.15V is at the`Adj' pin of IC1 (with respect tothe OV line). This of courseassumes that the circuit is asshown in Fig. 1.
Add to this 12.12V, thenominal 1.2V output voltage ofthe i.c., and we have a combinedoutput voltage of just a littlemore than 13.4V.
SemiconductorsLM338K 1
MR751 4
C3
IC1D1-4 A bridge rectifier(50V 6A min could be used)
MiscellaneousA 100VA 15V transformer, a3.15A fuse and fuse holder, the
a
I.e.d.(D5) is almost any red or green light emitting diode,
suitable heatsink (Maplin FL55K) and box.
Multi -Output
The unit can be made toproduce other output voltages,in the range of 1.2-30V. For thehigher voltages, some changeswould have to be made to thetransformer, diode and filtercapacitor circuitry.
Resistors2700.470Q2.7k0
CapacitorsMylar 160V220n 1
Electrolytic 24V working minim umMay be replaced with a
1uf 1C2
tantalum bead type
15 0000 1 C1
R2
R3R1
T
Fig. 1: The circuit diagram of the power supply. Capable of being made to givedifferent output voltages. See the text for more details.
Here is small table to helpyou acheive the output voltageyou need.
Vout New R1
I.5V 680.3V 39004.5V 68052
6V7.2V 1.2k09V 1.81(12
12V 2.2k0I5V 3k020V24V 5.1kS2
28V 61(52
This table is not meant to behighly accurate, but just to givean indication of the requiredresistance to replace RI. At thehigher output voltages, you mayneed to modify the resistanceslightly to get a more accuratevoltage output.
I hope you find the circuit asuseful as I have.
David Porter G4OYXLudlowShropshire
Heatsink
Insulatorbush
R1
Insulatorbush
Tag (OV) clampedto heatsink plate
Output voltageTo R3 and I.e.d. D5
From C1 positive terminal
IC1 is mounted on a large heatsink.The case (output) must be isolatedfrom the heatsink with the correctinsulating sheet.
a bead tantalum type
From Cl negative terminal
Tag (V) clampedto heatsink plate
Fig. 2: Diagramatic (pin -side), view of IC1, andmost of the other components, mounted on a largeheatsink. It is important that the LM338Kintegrated circuit is insulated from the heatsink.
Practical Wireless, March 1993 25
The prototypeh.f. mobileantenna as
built bY PeterDodd G31-°°'
My particular interest isexperimenting with antennas.The constructional practices I'mdescribing this month, willenable you to construct compactloaded antennas suitable forexperimental work.The design and location of amobile antenna is the key tosuccessful operation on anyamateur band. Because of spacelimitations on the vehicle, thevertical whip antenna is themost popular antenna regardlessof the band of operation.
Easiest To Feed
The vertical whip is easiest tofeed if it's at, or near, resonance.Because the greatest practicablelength of whip antenna is 2-3m,the antenna must be resonatedby the addition of a loading coil.
The loading coil may beplaced anywhere in the whip.However, the most efficient andpractical location is at the centre(see ref. *1).
To minimise losses, the coil
This month's 'Antenna Workshop' by Peter Dodd G3LDO, takes the formof a mobile project. Peter says that antennas for hf mobile working canbe cheap and easy to make, and to prove it he's come up with a verypractical antenna.
must be wound using thethickest wire possible. It shouldbe air -wound, with the widepracticable spacing between theturns. The diameter should notbe less than half the length ofthe coil.
The loading coil described inthis article, is designed for thehigher h.f bands, i.e. 14-30MHz.Despite this, by designing andmaking larger coils the rangecould be extended to the lowerh.f. bands.
Nowadays, many vehicleshave plastics bumpers. Somehave no bumpers at all!
So, a method has to be foundto mount the antenna directly tothe bodywork. If the car has atowing bar, it makes anexcellent antenna base mountingpoint.
The drawings in Fig. 1 and 2,show two ways to connect anantenna mount to the rear of avehicle that may or may nothave a plastics material bumper.The base mount is constructedfrom two pieces of anglealuminium bolted together.
The aluminium material wasobtained from a local scrap -yardas one length. Lengths of about80mm were then sawn off asrequired.
The plastics bumper shouldbe removed if necessary. Thenholes may be drilled in the car
body and the mount fixed inplace. The bumper can then bereplaced.
Base Plate
For vehicles withoutbumpers, a steel base plate mustbe used. It should be fixed to theoutside of the boot compartmentwith two or three bolts and nuts,as shown in Fig. 2.
For added safety andsecurity, when fixing antennamounts, lock -nuts or lock -washers should be used on allbolts. All the metalwork used toconstruct the mounting bracket,should also be cleaned andgiven a thin coat of grease, tominimise corrosion beforeassembly.
Please take care that, whendrilling and fixing items to a car,avoid wiring, hydraulic brakepipes, fuel pipes, or anythingelse that may affect the safety ofthe vehicle. If in doubt, a localgarage may be able to fit theantenna mount for you.
Once a metal mounting baseis fixed in position, it'srelatively easy to devise a baseinsulator. One ARRLpublication (see ref. $2)suggests a spring base to supportthe bottom insulated section.
The same article alsosuggests steadying the structure
with nylon cord. This seemsself-defeating, I think that it'sbetter to make the structurefairly rigid in the first place.
I use exhaust system U -clamps to fix the antenna to thebase. Suitable insulatingmaterial, such as strips ofpolythene or polythene tube willinsulate the antenna fromground. The method ofconstruction is shown in Fig. 3,the mounting -plate as seen frombehind.
If you're unable to findpolythene tubing of the rightdiameter to fit the bottomelement, it may be split so that itdoes fit. Splitting the tube willnot impair the insulatingqualities of the structure; thevoltage is fairly low at thebottom end of the antennaelement.
Coil Construction
Now it's time to look at coilconstruction. And at this point,I'll mention that in the past,loading coils have presented mewith constructional problems.
Where coil constructioninformation was available, itwas usually far too specific. So,learning from my owndifficulties with other people'sprojects, I've made thefollowing construction method
Fig. 1: One method of mountingantennas to modern vehiclesabove the 'bumper' (see text).
Car body outline-.
Two pieces ofangle bracket(metal)
Coaxial cablefrom Transceiver
Grommet
Antenna
.4-Plastics insulator
Exhaust Bracketclamps
Coaxial cablesealed at this point
Plastics bumper
Car body outline-.
Coaxial cablefrom Transceiver
Flat metal Grommeplate
Antenna
Angle bracket(metal)
Plastics insulator
Exhaust Bracketclamps
Coaxial cablesealed at this point
Fig. 2: Alternative method of mountingantenna bracket (see text).
Practical Wireless, March 1993
simpler, and it's less critical ofsizes and materials.
The loading coil is made upfrom 1.63mm (16s.w.g.) tinnedcopper wire. A coil wound for14 to 28MHz is approximately75mm in diameter and 45 mmlong.
To make the coil, wind thewire around a suitable former,such as a small jamjar. When thecoil is removed from the former,you have a low loss air -spacedloading coil. Two or threesections of plastics insulatingmaterial, can be used to makethe coil structure more rigid asshown in Fig. 4.
InsulatingMaterial
The insulating material canbe fixed to the coil, before thecoil is attached to the antenna.To do this, drill 1.8mm holes inthe insulating material. Theyshould be 4mm apart, one holefor each of the turns of the coil.
To start, place the insulatingmaterial together, and then windthe coil through the holes in thematerial. This process should becontinued until all the coilwindings are supported.
Move the insulating supportsaround the coil, so that it'ssupported in two or three places,depending on how manyinsulating strips you have used.The pieces can be held in placeusing a few spots of adhesive,such as an epoxy resin adhesive.The adhesive should be appliedwhere the insulating materialtouches the coil.
Tapping Points
The advantage of the openconstruction method I'veadopted, is that tapping pointscan be made on the coil. Thetapping can be achieved with aflexible wire link.
The flexible link is connectedto the lower element, by ajubilee clip just below the coil.The other end of the link isfitted with a small crocodileclip, which is clipped to one ofthe turns of the coil.
This tapping techniqueresults in turns being shortedout, so that one coil can be usedfor several bands. I'll describe amethod of setting the tappings,later on.
The insulator section isconstructed from an 80-90mmlength of plastics tubing. Thishas an internal diameter of20mm.
The antenna bottom elementis made from a 20mmaluminium tube. Don't forget,that if a different diametertubing is chosen for the bottomsection, then plastics tubing of asuitable diameter is alsorequired.
Slots, around 15mm long, arecut longitudinally at each end ofthe piece of plastics tubing. Thisis to allow it to be fixed tightlyto the antenna element when thejubilee clips are tightened up.
Telescopic Whip
The top section is tuneable,using a telescopic whip antennaof about a metre in length.
Additional top capacity, toincrease antenna efficiency, isachieved by an added horizontalcapacity element.
This capacity element can beseen in Fig. 4. It's made fromone length of 2mm steel rod,with legs some 320mm long.There's a spacing ofapproximately 30° between thelegs.
The telescopic whip antennaused in my prototype, has a basediameter of 12mm. I made areducer from two short lengthsof aluminium tube, 20mm and14mm diameter.
The 20mm section is taperedby cutting two or three 'V' slotsat one end. The 14mm tube isplaced inside the 20mm section.A jubilee clip is placed over the'V' cuts, and when it'stightened, the outer tube clampson to the inner one.
Small slots are cut in the14mm section of tube. This is sothat the top telescoping whipantenna section can be fixed,using a jubilee clip. This is fixedon to the antenna with jubileeclips in a similar way to thatshown in Fig. 4.
Connecting &Matching
Connecting and matching -upis very straightforward. Thecoaxial cable is split, in the bootof the car, near to the antennabase.
The centre conductor is fedthrough a hole in the body work.The braiding is connected to thebodywork.
This connection must have alow resistance. So, all paint andcorrosion around this connectionmust be removed and the cleanmetal work then smeared withgrease.
Several Bands
To use the antenna on severalbands with a link -tapped coil,the antenna must be resonatedon the lowest frequency bandfirst. To do this, remove the linkso that the coil has maximuminductance.
If you have a dip oscillator(dip meter), you can use this tomeasure the antenna resonance.It's a very useful accessory.
To adjust the antenna, startby removing the coaxial cableconnection from the antennabase. Then connect a one -turnlink between the antenna and thenearest earthing point, as shownin Fig. 5.
Couple the dip -meter intothis link, and then adjust the toptelescopic section until theantenna is resonant within theband. Finally, mark the positionof the telescopic antennaextension.
If you wish to use theantenna on other bands, connectthe coil shorting link to a pointon the coil, and then measurethe resonant frequency. Adjustthe position of the tapping pointfor the correct resonantfrequency. Do NOT adjust thetop telescopic section.
When the correct tappingpoint for the band is found,mark the point on the conductor
Coaxialcable
A
Cable sealedat this point
-4-Antenna
Angle bracketExhaust bracketclampsPlasticsinsulatingsleeve
Jubilee clip
Fig. 3: Details of anglebracket, showing use ofexhaust bracket clamps.The end of the coaxial cablemust be sealed and madefully waterproof.
Plastics tubing
Plastics spacer with2mm dia holes
spaced 4mm apart2 off
Fig. 5: Using a dip -meter, in conjunctionwith a coupling loop,
to tune the system (seetext).
Caia11.1
A'-4-with saw cutsPiece of aluminium tube
----almo-
Wino volI1M
WI 10--
acit hat
pal*
Detail of the'capacity hat'made from one2mm dia steel rod
20mm aluminium tube
Antenna
-One turn loop overcoil of the g.d.o.
r1 -.1,J -4-Gate (or grid) diposcillator
Fig. 4: Detailed view of loading coil with telescopic tuning section, showingmethod of winding coil through insulating material and capacity hat.
Practical Wireless, March 1993 27
with a marker pen. You can thenmove to the next frequencyband, and repeat the tappingpoint adjustment.
Load Impedance
Most mobile equipmentrequires a 505I output load.Since the feed -point impedanceof a mobile whip is quite low, amatching network may benecessary.
When installing the antennasystem, I recommend that amatching network is used. Asuitable network is shown inFig. 6.
The most convenient way ofachieving a suitable match forthe loading, is to increase theelectrical length of the antenna,so that its resonant frequency islower than the operatingfrequency. Although thisincreases the feed impedance, italso introduces inductive
reactance, which can becompensated for with a baseloading capacitor.
The matching capacitors maybe connected as shown in Fig. 7,and the capacitor value must bechanged for each band. This isbest achieved by having severalcapacitors in a box, andselecting them using a switch.
The value of the base loadingcapacitor will depend on theband in use, and the feedimpedance of the antenna. Thesevalues will, in turn, depend onthe actual installation.
I think capacitor values ofbetween 150 and 450pF wouldbe about right. But the finalvalues should determined byexperiment, as I'm about toexplain.
Experimental Process
You can start theexperimental process by
disconnecting the one -turn linkat the base of the antenna, andreconnecting the coaxial cableto the antenna. You should thendisconnect the shorting link atthe coil if you have fitted one.
Next, set the transmitter tothe 14MHz band. Then selectone of the larger values ofloading capacitor.
Now connect the transmitterinto the antenna system, throughan s.w.r. meter. Adjust the lengthof the telescopic top section andthe capacitor value for thelowest s.w.r. reading. This maybe a bit fiddly and could requiresome experimentation (see *).Finally, make a note of theoverall length of the telescopicsection.
Repeat the adjustments forthe other bands by connectingthe links to the marks obtainedusing the g.d.o. Do not adjustthe telescopic top section onceit has been set for the lower
frequency band! You shouldadjust the higher frequencymatching, by moving the coiltap point.
Tapping PointsSoldered
Once the coil tapping pointshave been found, thick wiretapping connections can besoldered to the coil in thesepositions. The link can then bemade using the brass insertsfrom a plastics connecting block(choc-block). This will providea better connection than acrocodile clip.
That's it! Your new home-brew h.f. mobile antenna isready for use. Good mobile -DX,and I look forward to workingyou on the bands.
(*) An easier way of matching the system, would be to measure theantenna feed impedance. This method of matching will be the subjectof a later article.
Further Reading
($1) Optimum Design of Short Coil Loaded HF Mobile Antennas,ARRL Antenna Book, 15th edition, pages 16-5 to 16-11.($2) ARRL Antenna Book, 15th edition, page 16-1.The ARRL Antenna Book is available from the PW Book Service,which is now to be found in the 'Arcade' section.
How Difficult? IntermediateHow Much? Approximately LW
(depending on materials to hand)
Shopping List
Telescopic whip section, 2mm steel rod (see drawing), hose -clips,aluminium tubing (see text), plastics tubing. Exhaust U -clamp typebrackets, epoxy resin adhesive, nuts, bolts and metal bracket materialto suit (see text). Coaxial cable, capacitors for matching network (seetext), sealing compound and grease for waterproofing entry holes andprotecting vehicle bodywork.
Top section
Capacity hat
Coil with shorting link
ar
To antenna
As shortas possible
Matching boxSmall metalscreenin box
Fixed to C1-6 see textmounting for valuesbracket
To s.w.r. meter
Fig. 7: A suitablematching system forthe mobile antenna.See text for methodused to select thecapacitors.
Fig. 6: The complete mobile system and antenna ready for adjustments. See textfor details on the tuning -up procedure.
s.w.r. meterMatching box
11_1, La
Coaxial cable outer earthed to car bodyThe inner connects to the antenna
Transceiver
Practical Wireless, March 1993
DON'T BE SITS GOOD
EDUCED BYOOKS.
BE SEDUED BY ITSPERFO CE.
If someone can make a
dual -band transceiver as
small and feature -packed as this,
who cares about its looks?
Especially if it's also so sturdy that it
shrugs off the knocks and shocks of a
lifetime's use.
And especially if it has a host of
product features, from built-in DTSS
and paging functions to alphanumeric
memory, simultaneous
dual -frequency receive and
message paging.
We'll tell you who cares. Kenwood
cares.
Which is why the TH78E isn't just the
neatest dual -band transceiver you can
buy, it's also the best designed. Right
down to thoughtful touches like the
sliding keypad cover.
So visit your nearest Kenwood approved
dealer, pick up the TH78E and admire
its ergonomic curves at close quarters.
Or simply take in the wonders of its
specification.
Either way, it's love at first sight.
Kenwood TH78E is part of a range of hand
portables from £240 to £430.
KEN 'WOODHOME AUDIO, CAR AUDIO, COMMUNICATIONS EQUIPMENT, TEST AND MEASURING INSTRUMENTS, TELECOMMUNICATIONS
Write your advertisement in BLOCKCAPITALS - up to a maximum of 30 wordsplus 12 words for your address - andsend it together with your payment of£2.35 (cheques payable to PW PublishingLtd.), or subscriber despatch label andcorner flash to: Donna Vincent, PWBargain Basement, Arrowsmith Court,Station Approach, Broadstone, DorsetBH18 8PW.Subscribers must include the despatchlabel bearing their address andsubscription number to qualify for theirfree advert.
Adverts published on a first -come, first -served basis, all queries to DonnaVincent on (0202) 659910.
Advertisements from traders, or forequipment that is illegal to possess, useor which cannot be licensed in the UK,will not be accepted.No responsibility will be taken for errors.
For Sale
AEA PK88 packet controller, £85.Sandpiper h.f. with 50MHz two elementmulti -beam as new, £140. Datong audiofilter FL3, £95. CapCo magnetic loop.AMA3, £180. Tel: Ruislip (0895) 676919.
American service manuals all models1936-42 Sparton, Emerson, Crosley,Belmont, RCA, GE, Admiral. Tel: (0702)522929.
Cambridge Instruments electrodynamica.c. test set, 0-500V 3 ranges 0-25A 5ranges, £20. Mains transformer 15V, 20Acentre tapped, £12. Atari 600XL computer,£10. Tel: (07991 30763.
Corsair 2 p.s.u., speaker, all filters, manual,boxed, one owner, mint condition, £850.Amtor AMT3 new - unused, £150. Fritzeltriband three element beam, boxed, oneyear old, wax inhibited, £350. H. JacksonGOGGI, 'Lessors', Kirkby -in -Furness,Cumbria LA17 7TE. Tel: (0229) 89635anytime.
BARGAIN BASEMENTCTE BS25 mobile p.s.u. and linearamplifier 25W output suitable for CTE,lcom etc., hand-helds (v.h.f.), £50. 3amp13.8V p.s.u., £12. 3.5-150MHz s.w.r. meter,£15. All plus postage, g.w.o. Robert GI7IVX,13TH R. Tel:106937) 62166 anytime.
Daiwa Rotator DR 7500 Suitable formedium h.f. antennas/larger v.h.f. arrayswith instructions, v.g.c. round controller,mint, £60. Pair 7MHz KW traps, £15.s.w.r./p.w.r. meter, almost new, boxedinstructions, £15. G2FZU, QTHR, Southwell,Notts. Tel: (0636) 813847 no offers please.
Datong ANF, £45. FL3, £80. Black JaguarBJ200, £90. FRT-7700, £25. ICS FAX 1, £175.Trio 9R59DS plus speaker, £65. Scopex4S6, £60. All items in g.w.o. Must collect.Tel: 070-621 8290 evenings.
Drake TR7 Transceiver with SPS7 powersupply: s.s.b. and c.w. filters fitted, receiveDC-30MHz, £565. Geoff G4ECF. Tel: (0483)570033.
Eddystone 898 dial assembly boxed,unused (see page 24 February issue). Bestoffer secures. Heathkit Laboratoryoscilloscope model 0-12U, £50. Tel: 081-4504844 daytime, 081-954 1750 evenings.
ERA Mkll Microreader used twice, £75.Kenwood HS5 headphones new, £20.BNOS 144MHz 100W Linear with Pre -amp,£30.
Pye PMR 70MHz communicationsequipment consisting of one base stationplus five mobile units, £60 o.n.o. Vanguardcomplete, £25. Peter G7FX0, 'Tanglin', 47Ulwell Road, Swanage, Dorset. Tel: (0929)425805.
Realistic PR02006 Hyperscan 400memories, a.m., n.f.m., w.f.m. as new, littleused, £160 plus postage. Tel: (04801 453228.
Ten-Tec 560 Corsair all filters plus 263 v.f.o.perfect, boxed manuals, £640 Trio R600
manual, £190. Coax switch 3 -way, £10.Shure 444, £25. Argosy c.w. audio filter,£20. Heathkit V7AU, £10, post extra. Tel:(07951 873100.
Tokyo Hy -power 160V 430MHz p.a. 3/10Win 100W out (mint), £260. Jaybeam D15/1523cms antennas (new), £45. Black Star Palvideo pattern/audio generator (mint)Daiwa electronic keyer unit, £39. PaulG4XHF. Tel: (0293) 515201 home or (0622)696437 work.
Trio TH-77E 430MHz hand-held hardlyused, charged three times, v.o.x . headset,mobile boot mount, quarter wave dualband, soft case, £250 o.n.o. Tel:10922)25770.
Yaesu FRG -7700 receiver with FRT-7700and FRV-7700 (two of) all boxed withinstructions perfect condition, £340.Complete also Novatel Prestel businessterminal unit with built in monitor, £50. Les.Tel: Borders Region (0450) 370937
Yaesu FRG -9600 MkII, 60-950MHz a.m.,f.m., s.s.b. receiver, mint condition, £225.Gary. Tel: 021-711 1553.
Yaesu FT -290 Mkll 144MHz multi -mode. Allaccessories, £350. Clip on 25W amp, £50.Portable black and white TV (small)v.h.f/u.h.f. multi standard ideal beginnersDXTV or travel, £50. Nick or Lindsey,Uxbridge. Tel: (0895) 236397.
Yaesu FT-747GX fitted f.m. module.Serviced by SMC recently, bill shown.Used receive only, £450. A0R2001 scanner,£175 or exchange new Datong speechprocessor for Yaesu, £60. Tom, Kettering.Tel: (0536) 522007 anytime.
Zetagi valved linear amplifier BV -130Pnew valves 10dB gain, 10W in 100 out,a.m./f.m., s.s.b., pre -amp, standby switch,wattmeter, mains 26-30MHz, £75 inc p&p.Tonna 144MHz power splitter N typeconnectors, £25 inc p&p. GORZI, Cumbria.Tel: (0946) 812092.
Wanted
Books. 101 Ways To Test Ham Equipment,Amateur Radio SSB Guide published byW. Foulsham Co. Ltd, Slough C-1965/8.Linguaphone cassette course French andGerman. Tel: (0229) 89635 anytime.
Coder T28 RX manual +c.c.t. AT5, CR45,w.h.y? Denco ranges one, two, all coloursespecially green Electroniques amateurvalve and transistor coils. Companyinfo/history on above makers. P. BrentG4LEG, 14 Stagelands, Cranley, WestSussex RH11 7PE. Tel: (0293) 532825.
Drake RR3 MSR2 DSR2 R4245 receiver,any condition working or not. Racal 1792bits. MAI 103A. Watkins Johnson v.l.f.receiver. Modern solid state receivers bySiemens, Dansk, Sait or Collins or w.h.y.?G3YFK. Tel: (0743) 884858.
E -Z match KW or SEM or KW107, KW207or KW109. Cash waiting. Contact Richard.Tel: (039861 215.
Eddystone models ECI 0, E835, 870, 870Aand all variants of above for cash. May beable to collect. Mr Lepino, Surrey. Tel:(03741 128170.
Yaesu FT -102 transceiver working or non-working, with manual if possible. MikeG4JXX. Tel: 021-773 8139 after 6pm.
Exchange
Kenwood SW -100A mini mobiles.w.r./p.w.r. covering 1.8- 150MHz/0- 150W in good condition for similar specbase type. Tommy G7LNG, QTHR. Tel:(07521 892175.
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BELFASTGM Electronics, 1-3 Evelyn Avenue,Belfast, Northern Ireland.Tel: 0232 471295
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BIRMINGHAMWard Electronics, 422 Bromford Lane,Ward End, Birmingham.Tel: 021 328 6070
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BRISTOLLowe Electronics, 79 Gloucester Road,Patchway, Bristol. Tel: 0272 771770
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CLACTON ON SEACoastal Communications, 19 CambridgeRoad, Clacton on Sea, Essex.Tel: 0255 474292
CORKIntronic Ltd, Windsor Hall,Glounthaune, Cork, Eire.Tel: 010 353 2135 4422
COUNTY TYRONETyrone Amateur Electronics, 44 High
Street, Omagh, Co Tyrone, NorthernIreland. Tel: 0662 242043
CUMBERNAULDLowe Electronics, Cumbemauld AirportCumbernauld. Tel: 0236 721004
DONCASTERAlan Hooker, 42 Nether Hall Road,Doncaster, South Yorkshire.Tel: 0302 325690
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FIFEJaycee Electronics, 20 Woodside Way,Glenrothes, Fife. Tel: 0592 756962
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HAYWARDS HEATHBredhurst Electronics, High Street,Handcross, Haywards Heath, WestSussex. Tel: 0444 400786
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NEWPORT PAGNELLPhoto Acoustics Ltd, 58 High Street,Newport Pagnell, Bucks.Tel: 0908 610625
NEWTON LE WILLOWSAmateur Radio Comms Ltd, 38 BridgeStreet, Earlestown, Newton Le WillowsMerseyside. Tel: 0925 229881
NORFOLKEastern Communications, CavendishHouse, Happishurgh, Norfolk.Tel: 0692 650077
NORTH HUMBERSIDEPeter Rodmell Communications, FieldHead House, Leconfield, NorthHumberside. Tel: 0964 550921
NOTTINGHAMR A S Nottingham, 3 Famdon Green,Wollaton Park, Nottingham.Tel: 0602 280267
PORTSMOUTHNevada, 189 London Road, PortsmouthHants. Tel: 0705 662145
SLOUGHLowe Electronics, London Heathrow,6 Cherwell Close, Langley, Slough,Berks. Tel: 0753 545255
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Construction
Many 27MHza.m.lf.m.ls.s.b. CBtransceivers, such asthe 'HamInternationalMultimode II', wereimported in to theUK. Although illegalon the UK 27MHzCB band, manyamateurs obtainedthe necessarypermission toconvert them to28MHz operation.P. E. Francisexplains how you setabout modifying therig.
Converting A 27MHzA large number of continental transceiversmanufactured by Ham International, found theirway into Britain. They originally appeared mainlyas a result of the upsurge in unlawful CB radiooperations.
One of these sets, the Multimode IL lends itselfnicely for conversion onto the 28MHz band.Fortunately, many radio amateurs obtained thesetransceivers, and the necessary permits to convertthem, before the Radiocommunications Agencystopped issuing new permits several years ago.
The rigs (once converted) can, of course, be usedlegitimately either as a straight transceiver or (withthe p.a. section removed) to drive a transverter.Once on 28MHz, they can prove extremelyeffective.
I've aimed the following article at the radioamateur who has one of these sets and wants to useit on the 28MHz band. Alternatively, I've no doubtthat there are amateurs who have the partly broken-down chassis of such rigs in their shacks. Licensedamateurs in this position, can quite legitimately usethese units as transverter drivers (as per the relevantRadiocommunications Agency directive on thesubject).
The Conversion
The equipment needed for the conversion needsto be little more than a power meter with a 5052dummy load and a frequency counter. You'll alsoneed a selection of trimming tools, some patienceand a 6.5536MHz crystal.
First of all, install the dummy load and powermeter onto the set. Then switch the set to Lo bandchannel 1, select f.m. mode and note that the outputfrequency is 26.965MHz.
On the underside of the transceiver, to the rightside of the rig, Fig. 1, look at the pins of ICI, aPLLO2A. Note here that pin 9, is soldered to thecopper track which is a permanent 5V rail. Thediagram, Fig. 2, shows the main board lay -out tohelp you locate the various components.
The pin 9 on ICI needs to be removed from itspresent 5V rail and reconnected to earth. Thismodification is best carried out by cutting away thecopper foil connection, using a sharp knife.
Cutting the track isolates pin 9. You then soldera jumper lead from pin 9 onto the earth copper foil,
which is just to the right of the 5V rail.Take care on soldering the jump lead to pin 9.
This is in case you bridge the gap that has been putacross the print, or you may short the 5V rail out.
This modification alters the logic signals to IC1,which is the phase lock loop. This procedure is vitalto the re -programming of its output frequency.
Note that after this stage of the operation, theoutput frequency on channel 1 is now 27.487MHz.We're getting nearer!
New Crystal Frequency
The next job to do, is to remove the crystal, Xl,which is on 10.240MHz. You then replace it withthe new crystal on 6.5536MHz.
Operating the microphone p.t.t. switch after this,will almost certainly result in no r.f. output. You'llnow have to adjust the voltage controlled oscillator(v.c.o.) block to get an output.
To obtain an output again, unscrew the ferritecore of the largest plastic v.c.o. block (alongsideIC1) with the microphone p.t.t. depressed until r.f.output suddenly appears. Unscrew the core a furtherhalf turn and then leave it alone.
The reason for the loss of the r.f. output is due tothe operation of special circuitry. This protectiondisables the transmit portion of the set, and isbrought into operation if the phase lock loop is in a`non -locked' condition.
Observe now, that the channel 1 frequency isnow 28.294MHz. At last, we're on 10 metres!
Output Acceptable
The rig's measured r.f. output will be acceptableover some 40 channels or more, but output will dropoff after that. So, some slight tweaking of the coresof: T1, T2 and T3 will now be required in order toachieve reasonable tandspreading' of power overthe full 120 channels.
If at any time, power output drops to zero or`chattering' of the r.f. output level occurs, it may benecessary to unscrew the v.c.o. block a little further.
That deals with all the frequency determiningadjustments, so now put the set onto 'Mid band',channel 60, and adjust the cores of T4, T5 and T6for maximum r.f. output. Next, adjust the cores inL7, L11 and L13, the r.f. driver and output stage
Copper foilNegative
Cut foilaround hereJumper leadfrom pin 9to earth
Fig. 1: Details of the p.c.b. modificationsneeded on the Ham International 27MHztransceiver, to prepare it for use on the28MHz amateur band. The samemodifications may apply to other similartransceivers held by licensed amateurs withthe necessary Radiocommunications Agencypermit to convert.
RV12
C3#°
a.m. r.f. pot
aT16
1.11111111.11I
L.1.1
L11
Q10
L7
Q9
E Q T6T4 T5
El
elv.c.o. block
IC1 nPLLO2A U
X1
O T2
T1
T3
Fig. 2: Diagram showing main board lay -out onthe transceiver, with main components andthose involved in the conversion indicated.
32 Practical Wireless, March 1993
Multimode Transceivertuning coils, for maximum output.
The cores may need to be stagger -tuned in orderto achieve a good, even spread of power over allchannels. It may be worth noting at this stage, thatby adjusting RV2 (the a.l.c. control) can give aslight boost to the s.s.b. output.
The control RV12, is the modulation percentagecontrol for the a.m. section of the transmitter. Thetransmitter is capable of up to 20W p.e.p. on s.s.b.,depending on the p.a. transistor type and how wellthe output stages have tweaked up.
Receive Adjustments
Next, switch the rig to receive and select a goodsteady carrier or strong station around channel 60,and start the adjustments of the cores in T7, T8 andT9. Aim for maximum signal strength reading, ormaximum noise in the event of there being littleband activity.
Again, some stagger tuning of T7, T8 and T9receiver front-end tuning coils may be needed. Thismight be required to avoid any sharp drop inreceiver performance, over the full coverage from28.294 to 29.476MHz.
It will be necessary to make a log of the outputchannels in terms of frequency, and the frequencyvariation available with the 'clarifier' control forobvious reasons. However, there is provision on therear of the set to install a frequency counter, whichcould be useful.
On this rig, the transmitter only, is usable ona.m., f.m. and s.s.b. modes but the receiver is only
operable on s.s.b. The reason for this, is that in theoriginal design, the frequency of crystalX1,10.240MHz was tapped off through C13, a 5pFcapacitor and mixed with another frequency of10.695MHz, giving a difference of 455kHz.
The 455kHz was of course the i.f frequencyused on a.m. and f.m. However, the now obsoletecrystal of 10.240MHz could well be built up on anexternal circuit board. The signal could be injectedinto C13, after first removing the C13 connection toone leg of Xl.
My suggested (extra) modification would servenicely for a.m. and f.m. modes. It could beparticularly useful if the set was contemplated foruse as a prime mover for a transverter to 144MHz,for example.
Since this article was aimed mainly at the h.f.bands operator, it was not considered too importantto dispense with the a.m. and f.m. facility. Thecrystal specified came from RS Components, andwas used for a clock project.
There's no reason why some other crystalfrequency couldn't be employed with the abovemodifications. But don't forget, output channels willof course vary from those quoted if an alternativefrequency is used.
The 28MHz band is very noise free, and manypleasurable hours can be spent having world-widecontacts. Even using relatively low power,providing a good antenna is used and bandconditions are good, you can work some excellentDX.
PW
Feature
Helical Earthing SystemsRichard Q. Marris G2BZQ takes a look at a rather unusual earthing system.Many amateurs have problems with installing earthing systems (r.f.). The mains earth isessential, as a safety measure, with mains operated equipment, but does not make a goodr.f. earth, and should not be relied on for that purpose.
The helical wound antenna is quite well known, but what is not quite so well knownis that a helical wound r.f. earth will often, but not always, work excellently. A typicalhelical r.f. earth is shown in Fig. I.
It consists of turns, of wire, wound around a suitable insulated round rod or tube.The formula established, at the QTH, for calculation of the length of wire needed for thewinding is:
492Length On feet=
FM Hz)
So, if we were interested in a frequency of 14.I MHz, the length of the helical earthwould be:
Length (II feet) - 492+10%14.100
After working out the maths, we arrive at a figure of 38.4 feet (II.70m)This could be wound on a length of I in diameter dowel (long broom handle) using
16/0.2mm pvc insulated flex which has a nominal o/d of 5.4mm; and is also /2 of mainslighting lead. The turns should be slightly spaced. Such a helical can be used throughoutthe 14MHz band. For a lower frequency band, such as 3.5MHz, then a larger diameterplastics drain pipe section is suggested with the length of wire worked out from the same
Fig. 1: Atypicalhelically -wound r.f.earth.
Transceive, 'mudto the band al Intense
(".'0'1111
formula. The idea can he tried for mono -band function and should be connected at thea.t.u.
Trial And Error
The positioning of such an earth is best established by trial and error. It should notbe laid on the floor, or ground, but uplifted to two or more feet, and a horizontal supportconsisting of the backs, of two wooden chairs, is useful to establish the best position.The earth can be tried at various angles to the antenna, or even hung out of an upperwindow, or propped at an angle against the wall.
There is a 'best' position where the antenna loading is best, but experience invarious apartments in the UK and USA, on I4MHz, has produced different angles, atdifferent QTHs, with various antenna types. A simple plug/socket arrangement, at thea.t.u., would enable individual helicals to be used on different bands.
For the s.w.l. interested in general short wave listening, it is suggested that a helicalcould be wound, for say 3MHz, on a length of plastics drainpipe, with a few taps to betried at the various higher frequencies. The drawing Fig. 2 shows an experimental layoutthat could be used over several bands.
Experimentation
A certain amount of experimentation is suggested.Whether a helical r.f. earth is tried for transmission and/or reception, it may well
solve a difficult earthing problem, especially for apartment dwellers and others whocannot run a short earth lead to ground.
Fig. 2: An experimental lay-out for a helically -woundearth, with a trapping facilityincorporated.
Transaaivw tunadto ths bad ol lowest
0000
O0000000
Coiled 'earth'
Practical Wireless, March 1993 33
Construction
The converted PyeOlympic transceiverready for action on70MHz.
Modifying The PyeOlympic P BandTransceiver
In recent years, ex-p.m.r. equipment has come onthe market which is capable of being used on the70MHz band. The Pye Olympic is one such rig.
The Pye Olympic transceiver actually comes in anumber of forms. For example, there's themotorcycle unit and the boot -mounting rig.
Both types come with a remote cable to a controlhead, which can be mounted at the rider or driver'sposition. The dash -board mounting unit is the morefamiliar of the three types, and it's seen quitefrequently at rallies.
Specific Bands
The Olympic transceivers are designed to operatein specific bands. These bands are: E (68 to
Fig. 1: Diagramshowing mainchassis of thePye Olympictransceiver, withmain sectionsindicated.
Fig. 2: The front-end inductorsection (seetext).
Mic r.f. p.a. LPF Antenna
..............a il:ii-a,60-a ct
2eE
13Z.E
E 2-c, Em 2'.-X
E ig g
- ca ccXcc
Xcc
XI-
I_
H111111111111
1=1 V=1
IC751
L8
C23
L7
IC 1I
L6
INEI
L5
Ini
L4
C9
L3
C5
L2
C1
L1
34
There's usually only one majorproblem when it comes tomodifying surplus p.m.r. equipmentfor amateur use, and that's whenthe source of supply dries up! But,Ken Ginn G8NDL has found plentyof the Pye Olympic transceivers,and now he's going to explain howto set about the job.
88MHz), D band (88 to 108MHz), C band, and soon through to A, for simplex operation.
There is however, another band, designated as P.This operates over two such bands (for example) Dand E, using a half duplex system.
These rigs can be found with the transmitterworking in the E band, and the receiver in the D.What has to be done to the rig is to convert bothreceiver, and perhaps the transmitter side also, toallow the rig to operate on 70MHz.
What I'm about to describe, is the modificationneeded to the rig to get a working P band rigrunning on 70MHz. The modification is aimed atkeeping the same performance as the original.
Identifying The Parts
It's best to start the conversion by identifying thevarious parts that need modifying. These are thereceiver front-end (marked AT'27879/4), the receivermultiplier (marked AT27877/4) and the transmitmultiplier (marked AT27881/5).
The rest of the boards and modules need nomodification. See Fig. 1, for reference.
Front End
The front-end module needs the most workcarried out, and this job will take an hour or so tocomplete. To begin, remove the module from the rigand open up the lid.
Now, you should lay the module down on thebench with the connectors nearest, and the Tetfertrimmers away from you. Look at the coils in theunit, and from right to left we have Ll through toL7 (refer to Fig. 2.).
The coils LI to L6 are air wound, L7 is woundon a 3mm former and L8 is a toroid. The coils L7and L8 are not touched.
Next, carefully remove coils LI through to L6.Take care not to damage any components which are
Practical Wireless, March 1993
Fig. 3: Diagram showingthe method used tomake the tapping pointson inductors (see textfor details).
L4 P1L7 TP2 L9
1it 2, I
el
a
Cl CI7
TP1 TP2 TP3 TP4
C27
L2 L3L4
0 0 0 0
L5 L6 L8L9 L10
I
Fig. 4: The receiver multiplierboard. To carry out themodifications the screeningcans have to be removed (seetext).
Fig. 5: Diagram showing thetransmitter multiplier board(see text for alignment details).
in the same screened compartment as the coils beingremoved. Once removed, the coils can be discarded.
When the old coils have been removed, ensurethat the plated -through p.c.b. holes are clear of anysolder. The job now is to rewind these coils to thefollowing instructions.
Coil Details
Take care when winding the coils. By followingthese instructions you should get the job completedwith few problems!
All the coils mentioned, are made up with 0.8mmdiameter enamelled copper wire. They should beclosely wound on a 6mm former (a 6mm drill willdo).
Ll 10 turns, tapped at 13/4 turns near theearthy end
L2 10 turns, tapped at 3 turns near the earthyend
L3 8 turns, no taps.L4 10 turns, tapped at 2 turns near the earthy
end.L5 8 turns, no taps.L6 10 turns, tapped at 23/4 turns near the
earthy end.The taps are made with some 30s.w.g. tinned
copper wire. A length of 'wrapping' wire with theinsulation stripped is ideal for this purpose (refer toFig. 3).
To make the construction of the coils more rigid,some epoxy -resin adhesive was used for fixing. Iapplied this to the internal surface of the coils, andthe technique makes handling the coils much easier,before the adhesive sets.
Once you've completed this job, the coils cannow be located into the board. Take care not to shortany of the taps against the side of the metalscreening.
The final modification on this board. is to put a3.3pF sub -miniature ceramic capacitor in parallelwith C23. This capacitor can be accommodated onthe track side of the board. The position of C23 isshown in Fig. 2. The front-end module can now bereplaced with the screening lid back into the rig.
Receiver Multiplier
The receiver multiplier board also needsmodification, to bring it to the required frequencyband. The screening cans of all the coils have to beremoved for this operation (see Fig. 4).
In this modification the following componentshave to be changed:
C9 This is changed to a 100pF sub-miniature ceramic capacitor, inside the screening
can of L3.C7 This capacitor is changed to 100pF
sub -miniature ceramic, inside the screening can ofL4.
C19 This capacitor is changed to 82pFsub -miniature ceramic, inside the screening can ofL6.
C17 Changed to 82pF sub -miniatureceramic type, inside the screening can of L7.
C27 Change this capacitor to a 39pF sub-miniature ceramic type, inside the screening can ofL9.
The above capacitors should be components witha lead spacing of 0.1in (2.54mm) to fit the p.c.b.correctly. This completes the mods to the receiver,and now the alignment can be carried out in thenormal way.
Aligning The Receiver
The next job, is to align the receiver. Thealignment is accomplished in the usual way, withthe typical set-up using a signal generator and amethod of reading SINAD if possible.
Listening by ear can work just as well with aspeaker. Start by setting up the rig with a crystal inthe appropriate channel, and select that channel.
Measure the voltage on TP1 (on the receivermultiplier board) with the aid of a multimeter.Connect the negative lead on the multimeter to thenegative supply to the rig, and the positive on themeter to the various test points. You then shouldadjust L3 and L4 for a maximum reading of around1.0V d.c.
Transfer the multimeter probe to TP2, and thenadjust L6 and L7 for a peak reading. Now re -tuneL3 and L4 for a maximum reading on the meter,around 0.5V with the probe still connected to TP2.
Now, prepare an r.f. signal generator to provideapproximately 10mV output. Connect it to theantenna socket on the rig at the test frequency, andmodulate it with a lkHz tone 65% system deviation(3kHz for a 5kHz system). Next, you should tune L9on the receiver multiplier for best quieting.
The next job is to adjust Cl, C5, C9, C13, C17,C21, C26 and L7 on the front-end module for bestquieting. The presets on this module can be adjustedwith a screwdriver, but the coil L7 needs a non-metallic tool for trimming.
A small knitting needle filed to the appropriateshape for the slug's slot, is the best alternative forthe job if a plastics tool is not available. Be carefulwith this coil as it is very fragile. You'll also findthat the trimmer C26, has quite an effect on theoverall performance of the receiver.
Should any coil cores be stiff, then the
Practical Wireless, March 1993 35
Conclusion
In conclusion, I shouldmention that I've havelost count of how manyrigs modified over thelast 18 months, of boththe boot and dash -mounting versions. Theboot -mounting versionlends itself tomodification to packetoperation very well, andI have modified two.With the modifications
for packet, I've had totake out the controlcircuitry and substitutemy own design, in theform of a PIN -diodeswitch. Thismodification can also beaccommodated in thesame enclosure, makinga more reliable antennachange -over system.
I hope you have asmuch pleasure fromyour converted Pye rigas I've done. It's a veryeconomical way ofgetting on to 70MHz.
application of a little localised heat will help to freethem. But take care, and don't overdo the heating oryou could melt the formers!
Incidentally, on all the Olympic transceiversconverted to 70MHz so far, I've found that by usingthis method the sensitivity is around 0.41.1V for 12dBSINAD. A couple of the receivers have evenmanaged down as far as the 0.21.tV level.
Transmitter Modifications
The transmitter modification is by far thesimplest of the three board modifications to make. Itonly requires six 27pF capacitor to be added to thetrack side of the transmitter multiplier.
There is an extra capacitors, across each of thefollowing components: C14, C16, C20, C23, C30and C36. The extra capacitors are mounted on thetrack side of the board.
Transmitter Alignment
The transmitter section alignment can be carriedout in much the same way as the receiver. In otherwords, it's done by adjusting slugs in the coils,while watching the resulting points of resonance onthe test points on that board.
Make sure that there is a crystal in the correctsocket, and a dummy load on the antenna socket.You'll also need a power supply able to provide 5Aat 13.8V.
Set the rig to transmit, but be careful as somemicrophones have a 40 second timer mounted in thecasing. The 'shaver' shaped type of microphone hasthis facility. The timer can make the tuning up alittle difficult, as it will release, and key up againthroughout the tune-up procedure!
Keep the transmitter keyed during the alignmentprocess. Looking at the transmitter multiplier (referto Fig. 5), you should then connect the multimeterpositive lead to TP1. Then adjust adjust Ll and L2for a minimum reading, before adjusting L3 for amaximum of around 8.0V.
Transfer the multimeter probe to TP2, adjust L4for a minimum. Now re -tune for minimum. Lastlyadjust L5 for a maximum of about 0.9V.
Transfer the probe to TP3, and adjust L6 for aminimum. Re -tune L5 for a minimum. Adjust L7for a maximum of about 8.0V.
Transfer the probe to TP4, and adjust L8 and L7for a minimum. Adjust L9 for a maximum of about12V.
Connect an ammeter in series with the powersupply (10A range). Re -tune L9 for maximumsupply current. Adjust L10 for a maximum supplycurrent, approximately 3.5A.
Output Power
You should check the output power if possible,and this should be over 15W. The rig should drawaround 3.5A from the power supply at 13.8V.
I have discovered some rigs that have givenoutput powers in excess of 20W. This is quitenormal, as some of the r.f. p.a. bricks used in theOlympic are capable of giving this order of outputpower.
In practice, the higher output p.a. stages areindistinguishable from the 15W type commonlyfound. Unfortunately, there are no external markingswhich give a clue to the type used.
You could be forgiven for thinking that the BandE model would tune down to 70MHz easily.Unfortunately, although the operating frequency ofthe original transmit frequency is near 70MHz, itproved difficult. In the rigs I've converted, Imanaged to squeeze 72MHz out of them, but wasunable to get down that extra 2MHz.
I discovered that the problem was because themultiplier stages would not operate as designed, andthey multiplied at a higher integer than intended.This is why the padding capacitors were used on thetransmitter strip.
Crystal Specification
For the 70MHz band, the crystals need toconform to the Pye T54J0 specification. Don'tforget to quote this specification with the crystalfrequency at the time of ordering. This informationwill give them all the information that they require.
Additionally, by informing the crystal supplier ofthe type of rig, and the fact that it is an f.m.transceiver, you'll also assist them to supply thecorrect crystal for the job.
TX crystal frequency. = TX frequency/12(MHz)RX crystal frequency. = (RX frequency +
10.7)/12(MHz)For example: transmit crystal for 70.450MHz is
5.870833MHz, and the receive crystal is6.7625MHz.
PW
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36 Practical Wireless, March 1993
There's an event with something of interest for allRadio Amateurs, SWLs and Computer enthusiasts.
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Your Guide to38 Practical Wireless, March 1992
lio & Computer ShowBLUE HALL
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12.00 - 2.00pm'DXpeditioning: Pacific and Africa' by Roger Western G3SXW
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Sunday March 14th
12.00 - 2.00pm'The Colour TV Repeater for London' by Adrian Hurt GOOJY
2.00 - 4.00pm'Morse Clinic' by Ron Ray G3NCL & Jim Lycett GOMSZ
Special Interest GroupsAir Training CorpsAmsat UKArnold G.C. & PtnrsBARTGEuropean DX CouncilGrafton A.R.S.Guide Dogs for the Blind
Hoddesdon Radio ClubInt. Short Wave LeagueMilitary Comms MuseumRemote Imaging GroupRoyal Naval A.R. SocietyWorked All Britain A/G
he 1993 Show
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Practical Wireless, March 1992 39
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Practical Wireless, March 1993 41
We asked keenoperator JohnLevesleyGOHJL/GC126 totell us about the934MHz band.Here's John's plainman's guide to thisenigmatic band.
Fig. 1: The CybernetDelta -1 934MHz CBradio, on the right ofthe operating bench,shared with a wide -band receiver, and anh.f. amateur bandtransceiver.
42
A User Guide to934MHzThe use of 900+MHz for CB goes back to thebeginnings of legal CB in the United Kingdom. Theoriginal proposals have been modified in bothfrequency and antenna specification since then, butin spite of these changes, and an embargo on theimport or manufacture of new equipment, the bandis still with us.
As with CB radio in general, only messages inplain speech can be transmitted. This is carried outusing frequency or phase modulated transmissions.
British Company
A British company, REFTEC, soon produced thefirst practical 934MHz transceiver and matchingantennas. There were three models in all, startingwith the MkI, now a little long in the tooth. TheMkII was a very nice radio and is still givingpleasure to many, and the REFTEC base station,which is pretty rare and resembles the flight deck ofConcorde.
Other early rigs were the Grandstand transverter(27 to 934MHz), and the very rare Westminsterdual -band 27/934 base station. The final successfulBritish set produced was the Uniace 400, but bythen came the imports from the land of the risingsun.
It didn't take the Japanese long to identify theUK as a market for 934MHz CB radio. They werealready exporting a similar system to Switzerland.The NPR Kestrel or Commtel was the first of theJapanese imports, followed by two similar hand-held models and the Cybernet Delta One rig.
If REFTEC deserve all the credit for getting934MHz CB started, and SELECTRONICS ofCanvey Island the credit for setting up the firstspecialist dealership, it was undoubtedly NevadaCommunications in Portsmouth who accelerated theband's growth with the Delta One rig.
The Cybernet Delta One established itself as the`Mini Cooper' of 934MHz. Small, neat, full offeatures, good ergonomics and reliable and it tookthe band by storm.
The only better looking sets I saw, were twoClarion transceivers, demonstrated by Jim Finch, agreat enthusiast for 934MHz, of Solid State
Electronics.These were
state of the artpersonal radiosystemtransceiversforSwitzerland,with all kindsof selectivecalling andcontrolfeatures. TheClarionshowed whatmight havebeen.
Because ofthe cost of the equipment, the service grew slowly atfirst. Comparative maps I made several years agoshow eight stations in South East Dorset in spring1984 when I first operated, doubling the next year,and doubling again in 1986.
Patchy Activity
The use of the 934MHz band was patchythroughout the UK, activity was confined to manygeographical pockets. The intensity of operationincreased southwards from Scotland, through theNorth of England and into Eastern and SouthernEngland.
In Wales, activity was mainly restricted to theNorth and South coasts of the principality. InNorthern Ireland and the Channel Islands, activitywas limited to a few dedicated operators.
The years 1986-88 were probably the vintageyears of 934MHz, with superb lift conditions. Therewas a peak in operator numbers and a steady supplyof good quality equipment.
Around this time, there was a serious blow. Thegovernment reallocated the 934MHz frequency to acommercial digital voice communication service (asort of super CB service for small firms or largecommercial sites).
Although this service has still not materialised,the authorisation to manufacture or import 934MHztransceivers was withdrawn. The existing 934MHzusers can continue to operate as long as theirstations are capable, although new equipment isvery scarce, and second-hand items are in shortsupply.
Despite continuing assurances that the bandcould continue to decline gracefully by naturalattrition over many years, a significant number ofoperators left the band in resignation, despair ordisgust.
There is every indication however, that the bandis now undergoing a regeneration, as equipment isbought and used by new operators. If a really goodperiod of lift on the band returns, then a totalresurgence of activity could happen quite suddenly.
The Specifications
Dismissed as a gimmick when it first appeared,`experts' said that stations would be lucky tooperate across the road with the specificationallowed. Indeed on paper it didn't look promising,low power with low gain antennas and high feederlosses.
The specifications were coupled with operatorswho were seen as lacking the technical backgroundto cope with the black art of working with thesefrequencies.
Remember that 12 -years ago when thesediscussions where evolving, it took a lot of skill forradio amateurs to get good performance from a1.2GHz system.
The proposed 934MHz band was popularilyderided as a `toytown' radio service for the massesby some older amateurs. The experiences of thepioneers in 934MHz showed that the facts did notmatch their predictions.
Line -Of -Sight
Like any u.h.f. frequency, day-to-daypropagation at 934MHz is more or less line -of -sight.However, as the frequency is suitable for radarapplications, it's subject to reflected and scatteredsignals. This scattering effect can lead to someirregular signal enhancement. This scattering can
Practical Wireless, March 1993
also send signals round corners, and produce someunexpected signal paths between stations. Ratherlike auroral propagation, but very much morelocalised.
Propagation both by ducting and refraction isalso quite common on 934MHz. Local morning orevening temperature inversions will often enhanceconditions. Also propagation over low-lying land orsea paths may be reliable over ranges well in excessof 150km. Stations in low-lying locations, but witha good take -off for their signals, will oftenexperience knife-edge bending of their signals.Atmospheric conditions over distant highlandridges, may also bend signals over the ridge anddown the other side.
Full blown tropospheric refraction propagation isspectacular on 934MHz, with sustained directionalpropagation over hundreds of kilometres on lowpower and with simple antennas. One confirmedcontact from was Jersey to County Antrim, some700+km.
After talking with amateurs in the USA abouttheir 900MHz allocation, I found that they regardthis band as similar to 430MHz, rather than 1.2GHz.
Antenna Location
Successful operating at 934MHz depends mainlyon your antenna location. In general, the higher andless obstructions, the better. Remember a 75-80mmwet leaf is a A.J4 reflector at 934MHz!
Mature trees in full (wet) leaf can attenuatesignals like a black -hole. I hate to be negative, but ifyou live in a deep hole surrounded by trees, beprepared to go mobile if you want to get anythingfrom the band.
On 934MHz, it is generally unsuitable for car tocar contacts, even over quite short distances. It isalso of limited suitability for car -base operationsover distances exceeding 7-10km. When used formarine mobile operations or from hilltops it's ratherbetter, sometimes with spectacular results during liftconditions.
The band is pleasantly informal, and is wellknown for the high standard of operating. Operatorsstick to a code of practice that is polite, friendly andsensible. We've not experienced some of the worstexcesses, seen on 27MHz, or for that matter, someamateur bands.
The (illegal) use of linear amplifiers is frownedupon, though the limited availability of them hasprevented serious abuse.
Power microphones are acceptable, but otheroperators soon let you know if your signal is over -the -top. Odd aberrations have been the results ofexcessive temporary enthusiasm, rather than seriousmisdemeanour.
Individual operators have tried out repeaters,phone patches, and various data communicationmodes, all of which are of course prohibited. Manyoperators and their representatives still maintain agenerally good reputation with the RadioCommunication Agency who, on the whole, havenot been upset by these little individual deviations.
Packet Radio
There is a desire amongst some 934MHzoperators, myself included, that nationally onechannel should be officially designated for use withpacket radio. I would hope that at least one to onecommunication, digipeating and the use of personalmail boxes could be considered.
Interference from cellular telephone services canbe a problem. The band is bracketed by mobilephone allocations, and some interference does occur.Interference may be reduced, but not eliminated, by
Practical Wireless, March 1993
switching off any receive pre-amplifier or by fitting a cavity filter.One easy way to avoid interference,would be to have the option ofoperating using horizontalpolarisation.
Normally, vertical polarisationbenefits mobile operation fromhilltops (few horizontally polarisedmobile antennas were producedcommercially). Even now, the mostuseful antenna is probably avertically polarised collinear.
There is though, some subjectiveevidence that horizontal beams aremarginally more effective on934MHz.
A station with no interferenceproblems could operate with a righthand circular polarised helical beam.This is a very effective antenna andcan work stations of eitherpolarisation.
Barrier Features
The band is populated withclusters of stations, separated by 'nogo' areas, usually high ground orother barrier features. Many operators seem to be intheir mid 30s, but the number of operators isdifficult to calculate.
There may be as many as 1000 active stationsstill on air, with half as many again temporarilysilent. Strangely enough many 934MHz users havegained, or hold, amateur licences. There are only afew junior operators, but a high proportion of ladieson the band.
The calling channel is usually channel 10 or 20.Except under lift conditions, it is quite normal tohear only one or two channels in use.
A popular aspect of band usage is mobileoperation from high ground, whichhas a large following in some areas.The conversation may be brief ifthere's lots of activity, though rarelyas concise as some amateur contacts.
During openings or large scaleducting, stations you normallycannot hear, appear as 9+40dBsignals. Confusion may reign as halfthe stations in Britain attempt to usethe 18 chat channels to work DX!
Vertically Polarised
Mobile antennas for 934MHz aremainly vertically polarised collinearsof various designs. There are somesmall collinears around, includingthe original REFTEC models thatlook like cellphone antennas.
Other antennas can be over ametre long. The most easilyidentified, are the Nevada mobilecollinears with their distinctiveorange base, and air -spaced phasingcoils.
Collinears make good base -station antennas as well, and manyare shrouded for weather protection.Directional antennas have mimicked amateur designantennas. Commercial models having beenderivatives of either loop or Yagis, quads, helicalbeams, skeleton slots and even dishes.
Many operators own a receive pre -amplifier,capable of boosting incoming signals by as much as
Fig. 2: The Cybernet rignestling behind thegearstick, ready for amobile session.
Fig. 3: The antenna formobile use, is a Nevadacollinear type on agutter mountingbracket.
43
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Add-on Digital Readout!The HOWES DFD4 is an add-on DigitalReadout for superhet receivers andtransceivers. You pre-set the IF offsetfrequency (up to 6 IFs with the optionalPMB4), and the DFD4 displays the truetuned frequency with a 100Hz resolution.For a top class finish we offer the CA4M "hardware pack". This contains a custom made casewith pre -punched anodised aluminium front panel, display filter, switch, knob, socket, nutsand bolts etc. Give us a ring to discuss adding digital accuracy to your radio!DFD4 Kit: £39-90 DFD4 Assembled PCBs: £59-90PMB4 Kit: £9-90 CA4M Hardware: £19-90
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44 Practical Wireless, March 1993
20dB. Firms such as Crestbyte, Nevada, Corona,RN Electronics and several other specialistmanufacturers have made internal, in -line andmasthead units.
Some masthead units incorporated an antennaswitcher unit. One even had an output amplifierstage at the masthead which lifted the power at theantenna back to the permitted 8W output.
Shock Price
An enormous shock to many, is the price ofcoaxial cables and plugs. On 934MHz you cannotcompromise on the quality of feeder and plugs.
From the start you should buy silver-plated N -type or BNC plugs and sockets at about £3-4 each.Cable, such as H100 or similar at £1+ a metre isrecommended.
The older UR67 is fine at lower frequencies. Butit's just not good enough for efficient operations at934MHz.
The 934MHz Club UK is, I think, the onlyspecialist organisation representing 934MHz users. Idon't think the Personal Radio Club of Great Britainis active any longer. If I'm wrong, sorry, pleasecontact the Editor a.s.a.p. to correct the mistake.
Until a couple of years ago the 934MHz ClubUK used to run a couple of contests. In the late 80s,
the contest was discontinued by the club committeedue to lack of support. The Club does run someaward schemes and also activity days.
Members congregate at some of the regionalradio rallys, like the Wimbome Hamfest in Dorset,where local operators have put on a stand for severalyears. For details of the club, contact: The 934MHzClub UK, Hon Sec Doris Spencer, PO Box 934,Featherstone, Pontefract, West Yorkshire WF76YZ.
Second-hand Equipment
For those of you looking to start on 934MHz,you'll have to use second-hand equipment (but notsecond-hand cables or plugs). A number ofadvertisers in PW once imported 934MHzequipment, and they are mentioned in the text. BrianHollins used to run a 934MHz Exchange agency,although he's not very active anymore.
Second-hand equipment is advertisedoccasionally, but you'll have to be quick. Before Ifinish I have one plea to those of you with a set, orsets, mouldering away and not being used. There area lot of people out there keen to get on the band.Please put the rigs on the market, for the sake of934MHz. You'll get a good price, and help keep theband alive. PW
Fig. 4: Available fromNevada, the basestation collinearantenna. Mountedhigh up it providesgood all-roundcoverage.
omng Soon...The SG -2000 HF Mobile Transceiver
In an effort to encourage more h.f. mobile working in the UK, Rob Mannion G3XFD brings news of an interesting transceiverfrom the USA, the SG -2000 which is featured on this month's front cover and which he hopes to review in PW very soon.
I've been a very keen h.f. band mobile operator for many years. For almost two decades I used my trusty old Yaesu FT -75, and it's still capable of world-wideQSOs on 14MHz, even when only running 30W p.e.p.
Unfortunately, here in Europe we just don't seem to go in for h.f. mobile operating as they seem to do in the USA. You've only got to see the car parks atDayton every year to realise how keen the Americans are on mobile working, particularly on 7 and 14MHz.
Dayton And Friedrichshafen
Last year, during my visits to the Dayton HamVention andFriedrichshafen Hamfest, I came across the SG -2000 h.f. mobiletransceiver, featured on this month's front cover. Although notprimarily designed for the amateur radio market, I found it to bean interesting concept.
At both the American and German shows the rig was installedin a sports car. The interest being shown (even by middle-agedradio amateurs like myself) was surprising.
As a result, we're hoping to have one of the transceivers toreview very soon. I hope to give the transceiver a thorough 'roadtest'.
The SG -2000 transmitter covers from 1.8 to 30MHzcontinuously in 0.IkHz steps, with ±10Hz frequency stability.The receiver covers the frequency range of 500kHz to 30MHz.
The transmitter has 150W output, and its rugged constructionwould seem to lend itself particularly well to mobile andmaritime mobile working.
Your Mobile Equipment
While the SG -2000 transceiver equipment review is underway, I would be very interested to hear about your mobileequipment. Do you operate h.f. mobile? If you do, PW wouldlike to hear from you on this very neglected aspect of amateurradio in the UK.
In the meantime, I'm pleased to say that there are rumours ofnew products for h.f. mobile on the way from variousmanufacturers. You can be assured that we'll keep you informedof developments as they surface.
So, having brought you a sneak preview of the SG -2000, I'vereally got to try hard and get one to review. Watch this space, andif you're keen on h.f. mobile working, please let us know aboutyour activities.
Although not originally specifically designed for the amateurradio service, the SG -2000 has been proved to be a very ruggedtransceiver, and it should prove to be useful for the mobile and
maritime mobile operator. Practical Wireless hopes to reviewone of these rigs in the near future.
... From TheUSA
Practical Wireless, March 1993 45
Bits & BytesThe Computer In Your ShackYour response tothe first 'Bits &Bytes' wasoverwhelming -from both readersand professionalsthere are manyinteresting items toreview. However,due to spacelimitations, someitems will have tobe left until nexttime.
Fig. 1.
Johnny Brown G3LPB is a 'Dragon' collector (thecomputer that is!). He's an avid 'fixer' of all the older typemachines.
Johnny is a 'hoarder' and has spare parts and softwarefor many computers. If you think he can help you in anyway, why not drop him a line.
Please make sure that you include return postage andpacking. Johnny's address is: 45 Marlborough Avenue,Falmouth, Cornwall TR11 4HS.
John Bellis GD7KQX has a PK232 and a VIC 20. Hehad the packet system running when using a borrowedCM, but no joy with the VIC 20.
John has Pacterm for the VIC but when the firstcommand comes onto the screen it all locks up. If youhave the answer would you please let me know, or contactJohn direct, he is QTHR.
Richard Gulliver G4EDQ wrote to me from Germany,and asked me to bear in mind the none -PC users. Noproblem Richard, this is an 'all computers' column. I madea couple of phone calls and managed to get some usefulinformation for Commodore users, see the 'Club Spot'elsewhere in 'Bits & Bytes'.
Vic Flowers G8QM needs some amateur radiosoftware, plus 3in discs, for his Amstrad PCW 8512. Theonly source of CP/M software I know is the PDSL (fulldetails elsewhere in this article).
If any of you have any amateur radio software for theAmstrad PCW, or know of a source of such, plus also thesource of 3in discs for these machines, please let me know.I'll pass the info on to Vic, and also include it in the next`Bits & Bytes'.
BASIC Listings
It has been suggested that I print program listings inBASIC in this column. But due to the fact that allcomputers use their own dialect of BASIC (plus, not allreaders would find this of interest). I don't feel this is agood idea. However, what do YOU think?.
Shareware
The other thing that's been bothering a lot of you, isthe meaning of 'Shareware'. As I'll be reviewing a lot of'shareware' programs over the coming months, I'll give ashort description now.
Shareware programs are commercial programs that aredistributed via the public domain. They're available on a'try before you buy' basis, for an evaluation period(normally around 30 days), before parting with your cash.
You are allowed to give copies to your friends, etc. If,at the end of this period, the software is what you want,you are then expected to buy it by sending your money tothe author or his agent. This will get you the latest copy ofthe program, plus news of updates, etc.
There are libraries where you can buy discs containingthese programs. I have listed those who have contacted meso far. Any others will be listed as and when I hear fromthem. (I would especially like to know of any sharewarelibraries for non PC computers).
The Public Domain and Shareware Library (PDSL).Tel: (0892) 663298, speak to Rod Smith G4DQY. Ask himabout the `Libris Britannica' CD. WOW!
Shareware Marketing, 3a Queen Street, Seaton, DevonEX12 2NY. Tel: (0297) 24088. Also, Paul Sergent G4ONF.Paul doesn't run a library, but does handle the registrationfor several shareware programs. Tel: (0603) 747782.
Second User IBM
I bought a 'second user' IBM XT a few weeks ago. Itwas a model 5150, no books but in very good workingorder. It has 640K RAM, two 360K 5.25in floppies, andcame with PC -DOS 3.3.
The machine was made in 1982. The system unit andmonitor are in pristine condition, the keyboard is a bit dirtybut will soon get cleaned. I gave £50 for this and am veryhappy with it. I shall be putting a hard disc in this machinesoon, so I will feature that as a future project for thesepages.
I also got hold of a none -working (then, but not now)Spectrum. This is built into a DKTronics case and includesan Interface 1 plus power supply. It also includes aMicrodrive unit, but no cartridges. I would be pleased tohear of a source for these, especially with 'HAM' softwareon them. This machine will come in handy for reviews in'Bits & Bytes'.
The other thing I need is an Atari STFM powersupply. I have a friend's one here, he cannot afford a newp.s.u. and this one is beyond repair.
Okay, so that's an idea of what 'Bits & Bytes' is allabout. Any help I get with these items will be publishedhere.
This Month's Review
The first item for review is a book, Basic PacketRadio, written by Joe Kasser W3/G3ZCZ. Joe is well-known as the man behind `Lan -Link'. It comes with a diskcontaining a copy of Lan -Link.
46 Practical Wireless, March 1993
Regular Feature by Peter Hunter GOGSZ
Basic Packet Radio has over 360 pages. It's extremelywell -written, very informative, and is ideal for the absoluteraw beginner, as well as the veteran. The many chaptersexplain "everything you always wanted to know aboutpacket, but have been afraid to ask"! This book alsocontains the entire Lan -Link manual.
If you own a PC and a TNC and you want to do thingscorrectly from the start, and use the best softwareavailable, then this may be just what you are looking for.The price is £19.95 (plus £2.50 p&p).
For a copy of Basic Packet Radio, plus information ofall the other programs written by Joe Kasser, contactTerry Dansey GOBIX at Readycrest Ltd., PO Box 75,Chatham, Kent ME5 9DL. Tel: (0634) 687168. Manythanks to Joe for the review copy.
Shareware Marketing sent me a couple of discs to lookat. The first one is called "PC TRACE" (disc No.EN15)and is a PCB Design program. The other disc contained aLogbook program called: "LOG-EQF' (disc No.HR6) andis an electronic logbook. I will be reviewing these in futureissues.
Siskin Electronics sent me a PACTOR Controller forreview. No room in this issue, but watch this space. If youneed anything for Data comms, contact the lads at Siskin.Tel: (0703) 207155.
If Slow -Scan TV or FAX is where your interests lay,then this may be of interest to you. Comar Electronics sentme their PC Slow -Scan TV and PC HF FAX v 6.0 forreview. As both of these use the same items of hardware,and both operate in much the same way, the main reviewwill be of the SSTV system.
Photograph Fig. 1, shows what you get for yourmoney. The handbook is very informative, as well asextremely easy to follow. The disc contains all thesoftware, including an INSTALL program. The hardwareconsists of the Demodulator (for receive) and (optional onthe HF Fax) the Modulator (for transmit). TheDemodulator is built into the casing of a standard DB25pin plug, which plugs directly into the serial port of yourcomputer.
The lead from the Demodulator plugs into yourreceiver (or receive side of your transceiver). If you areusing the Modulator as well, then this plugs between thecomputer and the Demodulator. The lead from theModulator goes to the Mic socket of your transmitter.
The cassette tape helps you to get everything set-upcorrectly, and gives you practice at receiving 'live' signals.
To run PC Slow -Scan TV you will need any PC thathas at least one Floppy disc drive and 640K of systemmemory (RAM). Almost any monitor is okay for the FAXprogram, but you need at least a VGA monitor for thisnewest version of Slow -Scan TV. If you want to print yourpictures, then both programs will accept all 'popular'printers. Your computer will also need a Serial (RS232)port (plus printer port if using a printer) and MS (or PC) -DOS 2.1 or higher.
The PC Slow -Scan TV is completely menu driven,and leaves you in no doubt as to what to do or how to do it.Once you have tuned in the signal, you just press the(R)eceive key to start 'Digitising'. When the whole picturehas been received, it will then be 'read' onto your screen.To send a picture you just press the (S)end key. Thisdisplays a new menu, which allows you to send a'currently loaded' picture or one from your .GIF or .PCXcollection. In RX and TX mode all `standard!' modes arerecognised and used. This includes 'Martin', 'Scottie','Robot', 'AVT', etc., in Colour as well as B&W.
A built-in Tuning Oscilloscope helps you get the bestpossible results, and full editing facilities allow you to editpictures.
I used a couple of pictures from my '.GIF' collection,loaded them into the SSTV program and edited them withmy callsign, etc. Whilst I have received lots of very good
pictures from stations on h.f.(see Fig. 2 as an example), Ihave only, so far, transmittedpictures on v.h.f.
This complete package,whilst being very sophisticatedand complex, is so very simpleto use. Obviously I have a few'gripes' about the way it doesthings. Like having to load apicture onto the screen beforeyou can transmit it (rather thansending it straight from the filelist). As I've never tried anyother SSTV packages it'simpossible to makecomparisons. However, considering all the features, andease of use of PC Slow -Scan TV, for the price, I feel itmust be worth further investigation.
At the time of writing this, I haven't been able to findany h.f. FAX stations, so I can't report on the transmit sideof that program. However, I have received lots of verygood weather maps and charts. As the two programsappear to look and work the same, and both use the samehardware units, I have no doubt that PC h.f. FAX will givethe same results (and drawbacks!). The frequency I foundmost activity on was 14.230MHz u.s.b.
PC Slow -Scan TV costs £135.48 (plus £3.25 p&p). PCHF FAX v 6.0 costs £116.33 (plus £3.25 p&p). For thissystem the optional Modulator (for TX) is £59.80.
For either of these products, plus information aboutthe other items in this range, contact Peter Cotton atComar Electronics, Unit 10, Samuel Whites Estate,Medina Road, Cowes, Isle of White P031 7LP. Tel: (0983)200308.
My thanks to Peter Cotton for the review items. Alsoto Alan GOKRU for the hours of fun and enjoyment hegave me whilst in two-way SSTV QSO.
Well, that's it for this month. Keep the letters andgoods coming. Everything of interest will get amention/review eventually. Usual contact routes, viapacket GOGSZ @ GB7LDI.#35.GBR.EU. Telephone orFAX (0603) 748338. Post to: 2 Mayes Close, Bowthorpe,Norwich NR5 9AR. Till next time, 73 de Peter GOGSZ.
Flg. 2: A slow scan TVpicture 'grabbed' fromthe screen.
CLUB SPOTTHIS SPACE IS FOR YOUR CLUB!
Amiga AmateurRadio User Group
Club (C641128)CommodoreNo
No fee.
fee.
Send an A5 s.s.a.e. (24p) to:Paul M. Timmins
GONDV (@ GB7S )
Bob Wellbeloved G3LMH60 Bramwell Street
8 Orchard CloseNethertSheffield
South Wanton S3 7PA
WinchesterHampshireS021 3EY.
Come on dub secretaries, let's hear from you with
news and views on the radio computing scene!
Computing In Radio Special Issue
Look -out for the May Issue of Practical Wireless, it is aComputing In Radio Special.
I look forward to seeing you then! Peter GOGSZ.
Practical Wireless, March 1993 47
Feature
We've got a mobile`theme' this month.As many of us userepeaters whenwe're workingmobile, StanCrabtree G3OXCthought he'dsurprise us byrevealing thatrepeaters are almostas old as radiocommunicationitself!
Fig. 1: The firstrecorded wirelesstelegraphy repeater,built for service inBelgium by EmilioGuarini.
48
Back To The FutureTo The First Repeater in 1901!You might be forgiven for thinking that radiorepeater stations were a relatively modem idea. Thesystem nowadays, is confined to frequencies in thev.h.f. range and above, and serves to extend therange of radio communication for fixed and mobilestations.
Today, the modem repeater aids communicationswhere difficult or unsuitable terrain exists betweentwo stations. The use of such equipment also allowsportable equipment to employ much lower power.
Many people will be surprised to know, that thefirst repeater was reported to have been used inBelgium as far back as 1901! It was used to providea wireless telegraphy service between Brussels andAntwerp.
Effective Range Limited
In the early 1900s, the effective range of wirelesstelegraphy using long waves was limited. A range of160km was possible over the sea, but propagationover land was reduced to less than a quarter of thisdistance.
Although tuning had been introduced after afashion, the significance of resonant circuits was not
thoroughly appreciated. After all, it was the veryearly days of radio!
One of the problems that faced the Belgianauthorities, when they decided to set up the newsystem of communication, was the distance of 40kmbetween the two principal cities of Brussels andAntwerp. A further difficulty was the hilly groundbetween the two locations.
Countryman Of Marconi
Coming up with the answer was Emilio Guarini,a countryman of Guglielmo Marconi, born andbrought up in Puglia, Italy. By coincidence, animproptu change of direction made by him, wassimilar to that made by his fellow Italian.
At the age of 18, Emilio was attending college atTrani, but became disillusioned and frustrated at hisrate of progress. On impulse, he quit his studies anddecided to go abroad to widen his experience. Butwhere Marconi chose England because of familyties, Guarini for some reason opted for Belgium.
Continuing his studies in electrical engineering,
Emilio's progress was rapid. In 1900 at the age of20, he submitted a paper to the Academie desSciences in Paris on the role of the antenna andearth in electrical wave propagation.
Hertzian Waves
Intrigued with the current development ofHertzian waves, Guarini also put forward the idea ofwireless repeater stations every 800km or so. Usingthis technique, he suggested any area of the earth'ssurface could be covered - and it would beespecially useful for polar expeditions which werebeing considered at that time.
Emilio Guarini got his chance to put his theoryinto practice in late 1901. This is when the Belgiangovernment approached him with the idea of theBrussels -Antwerp link.
Guarini chose as his repeater station the town ofMalines, mid -way between the two cities. It wasalso important that it was on elevated ground.
Substantial Task
There was a substantial task ahead. Apart fromthe complexity of the repeater section, the basicapparatus in 1901 was very rudimentary.
On the transmitter side, there was the inductioncoil, spark gap, Morse key and capacitor. Thecapacitor, in those days, was usually in the form ofLeyden jars.
For reception, the coherer was being used as adetector. When conduction occurred, a circuit wasmade to a relay coil. The relay in turn operated arecording pen which endorsed the Morse characterson a paper tape, driven by a clockwork mechanism.
Land Repeater
In the land telegraph system, the introduction ofa repeater presented no great problem. By means ofa polarised armature, a local battery was switched inand out of circuit to follow the Morse characterskeyed at the source station.
However, for wireless telegraphy therequirement became more complicated. Despite this,the basic system appeared plausible enough.
Wireless waves reaching the antenna wouldactivate the coherer. This would switch in a relaycircuit, adjusted so that it would close the inductioncoil circuit creating the spark and radiating theenergy.
On test, this newly transmitted wave was foundto interfere with the weaker incoming signal and thecoherer was 'choked'. Even with the relatively slowsignalling speeds in use (rarely above eight wordsper minute at this time) - the system proved to beinoperable.
Improving The Design
Guarini set about improving the design until itworked correctly. Unfortunately, it only workedsuccessfully after the time and work had increasedthe cost to nearly $10 000, a considerable sum inthose days.
His first job was to enclose the coherer and thesensitive relay in a metal box. This providedshielding to the receiving circuits to a great extent.
Practical Wireless, March 1993
Secondly, Guarini dispensed with theconventional idea of including the coherer in serieswith the antenna and the ground. Instead, thereceiver circuit was fed via a small coil arrangement(virtually a step-down transformer) which served toisolate the coherer.
Possibly, by coincidence, this idea was rathersimilar to the 'jigger' arrangement that Marconi haddeveloped during trials with the Royal Navyvessels.
Using the isolating arrangement, ranges wereconsiderably increased, but the Marconi Companyhad not made their existence generally known. As areport published at the time stated, the inclusion ofthis device 'prevented atmospheric electricity whichgathered on the aerial wire from influencing thecoherer'.
A Blondel type of coherer was employed, usinglarge nickel filings with traces of silver. The mixturewas then enclosed in a glass tube, which was thenevacuated.
Further Experiments
After further experiments, the young inventorinserted a relay operated antenna switch, activatedby received signals. Unusually, this also served as aMorse key and controlled the power supplied to theinduction coil.
An illustration of the repeater apparatus is shownin Fig. 1. The Ruhmkorff induction coil, mounted atthe top of the assembly, provided a 10in spark whensupplied from strorage batteries with a capacity of
between 6 and 9A. In operational use, the spark gapwas reduced to 6in.
The condenser was formed by the bank of fiveLeyden jars, seen on the right of the coil. Theantenna switch is shown in the left foreground,mounted on an Ebonite strip supported on tworound boxes.
Between the latter mentioned equipment, is themetallic box containing the coherer and internalinstruments. On the right of the table, an ammetershows the flow of the current to the Ruhmkorff coil,this being regulated by the setting on a sliding typewire resistance positioned below it.
Guarini Speciality
Antennas were Guarini's speciality, and he spentsome time before coming up with the design shownin Fig. 2. The antenna consisted of cable made upfrom seven strands of wire, each being 9mm indiameter.
The antenna was 33ft long, and was made up of50 parallel wires arranged in a cylindrical form. Theantennas were erected 90ft high. In Brussels, theantenna was attached to bamboo poles to theColumn of Congress. At Malines, the antenna wasattached to the tower of Saint Romhaut, and atAntwerp to the steeple of Notre Dam.
Emilio Guarini never achieved the acclaim orfinancial success of his countryman Marconi.Despite this he contributed much to the progress ofwireless communications in the early days.
PW
Fig. 2: Antennas wereGuarini's speciality andthis is the design usedin conjunction with the'first repeater' (seetext.
Radio Diary Practical Wireless & Short Wave Magazine in attendance.
If you're travelling long distances to rallies, it could be worth'phoning the contact number before setting off, to check all is well.
February 14: 2nd Northern Cross Rally will be held at Rodillian School, A61 betweenLeeds & Wakefield. Usual dealers, ample parking, bar & refreshments, Morse test.Talk -in S22. Dave Gray on (0532) 827883.
February 21: The East Coast Amateur Radio & Computer Rally will be held at ClactonLeisure Centre, Vista Road, Clacton -on -Sea, Essex. Doors open 10.30am. Richard(0255) 474292.
February 21: The Barry ARS Rally will be held at the Barry Leisure Centre. Colin LakeGWOLBJ on (0222) 530070.
February 27: Tyneside ARS 5th Annual Rally will be held at the Temple Park LeisureCentre in South Shields. All usual trade stands, free parking. Talk -in S22. All theamenities of the Leisure Centre, including heated pool & gymnasium. Jack PickersgillGODZG on 081-265 1718.
February 27: The Bredhurst RATS Annual Rainham Radio Rally will be held at theParkwood Community Associations Hall, Parkwood Green, Rainham, Kent. Nearjunction 4 of M2 motorway. Talk -in S22. Kelvin Fay GOAMZ on (0634) 376991.
*March 13/14: The London Amateur Radio & Computer Show will be held at PickettsLock Centre, Ricketts Lock Lane, Edmonton, London N9. Large trade presence, freeparking, lectures, disabled facilities, Bring & Buy, special interest group section. Talk -in on 144 & 430MHz. (0923) 678770.
March 13: Lagan Valley ARS will be holding their Annual Hamfest in the Nurse'sRecreation Hall, Lagan Valley Hospital, Lisburn. Trade stalls, Bring & Buy,refreshments, QSL bureau, club stand. GIOGDF, QTHR.
March 21: Tiverton South West Radio Club Mid -Devon Rally will be held at the PannierMarket, Tiverton. Easy access, only minutes from junction 27 on the M5. Two halls oftrade stands, free parking, Bring & Buy, snack bar. Club room bar open throughout day.Doors open 10am, talk -in S22. G4TSW, PO Box 3, Tiverton, Devon.
March 28: Bournemouth Radio Society's 6th Annual Sale will be held at KinsonCommunity Centre, Pelhams Park, Millhams Road, Kinson, Bournemouth. Doors open11am to 5pm. Talk -in from G1BRS on 144MHz S22. Amateur radio & computer traders,clubs & specialised groups. Refreshments. Admission £1, including free raffle ticketIan G2BDV on (0202) 886887.
March 28: Pontefract & DARS will be holding their 13th Annual Components Fair &Springtime Rally at the Carleton Community Centre, Carleton, nr. Pontefract. Admission
by prize programme, three prizes plus free prize draw for lady visitors. Traders, Bring &Buy, bookstall, licensed bar, hot & cold snacks. Free car parking. Talk -in S22. Car bootspaces will be available. Colin Wilkinson GONQE on 10977)677006.
April 18: Marske-by-the-Sea Radio Rally will be held in the Marske Leisure Centre,High Street, Marske-by-the-Sea, near Saltburn. Doors open 11am. Usual traders, Bring& Buy & refreshments. Talk -in S22. Mic G7ION on (0287) 610030.
April 18: Cambridgeshire Repeater Group have their Amateur Radio Rally at PhilipsTelecom PMR - Catering Centre, St. Andrews Road, Chesterton, Cambridge. Tradestands, Bring & Buy, Auction, hot food & drinks. Doors open 10.30am. Mike G6COQ on(0223) 358985 Ext. 3310.
April 26: The Bury (Lanchashire) RS will be holding another Hamfeast/Rally at theLeisure Centre, Bolton Street, Bury. Laurence G4KLT on 061-7629308.
May 3: Dartmoor Radio Club Rally will be held at Yelverton War Memorial Village Hall,Meavy Lane, Yelverton, Devon. Doors open 10.30am. Talk -in S22. Ron G7LLG on (0822)852586.
May 9: The 9th Yeovil QRP Convention will be held at the Preston Centre, Monks Dale,Yeovil, Somerset. Featuring lectures, displays of home-made QRP equipment & vintageradio, on -air QRP stations & trade stands. Refreshments, doors open 9am, admission£1.50, talk -in S22. This convention is not a rally, but a convention for amateurs not onlyto attend interesting lectures about the technology & practice of low powercommunication, but also to meet other QRPers. There will also be the usual friendlyQRP Contest on 3.5 & 7MHz, during the evenings of the previous week. This event isknown as the QRP 'Funrun'. Peter Burridge G3CQR, 9 Quarr Drive, Sherbourne, DorsetDT9 4HZ. Tel: (0935) 813054.
May 16: The 2nd National Vintage Communications Fair will be held at the NEC,Birmingham. Doors open 10.30am to 5pm. Hundreds of items for sale, including vintageradios, telephones, gramophones, jukeboxes, radiograms, etc. Admission will be £3.Jonathan Hill on (0398) 331532.
May 16: The Parkanaur Rally will be held at the Silverwood Hotel, Lurgan, Co. Armagh.Doors open 12 noon. Admission £1. Plenty of parking. Usual traders. Refreshmentsavailable. Talk -in S22. All proceeds of this rally will go to the Stanley Eakins MemorialFund, a very worthy charity. W. A. Hutchman, 35 Carlingtord Park, Newry, Co. Down,N. Ireland BT34 2NY.
Practical Wireless, March 1993 49
PAT GOWE N G 3 I 0 R
he Shuttle AmateurRadio EXperiment,SAREX for short,will be very activethis year. If no
changes come about, thefollowing will be the dates ofNASA's Shuttle flights thatyou may be able to QSO.
The STS -55 launch willfly on February 25 for a nineto 11 -day mission carrying145.550MHz voice andpacket using the windowmounted antenna.Commander Steve NagelN5RAW, and PilotCommander Jerry RossN5SCW will be theoperators.
Also running will be433MHz voice f.m. from theGerman SAFEX radioamateurs aboard the carriedD-2 SPACELAB module. Theywill use a dual -band whipantenna mounted on theexterior of Spacelab.
They also hope totransport the 145MHz SAREXtranceiver across for sometwo band tests. Sadly thisflight will have only a 28.5°inclination, and so will bebelow the north Europeanhorizon at all parts of theorbit.
Nine Days
The following STS -56mission planned on March23 for nine days duration willalso have a SPACELAB. Theinclination of 57° will besuperb for all of Europe,giving daily passes right overthe top of the UK.
The mission will carryf.m. voice, packet, SSTV andan AN uplink. The operatorswill be Commander KenCameron N5AWP, KenCockrell KB5UAH, MikeFoale KB5UAC, and EllenOchoa KB5TZZ.
The third 1993 SAREXmission will be aboard STS -57, also carrying Spacelab,is currently scheduled forApril 29. It should be aloftbetween seven and ninedays, but again a 28.5°inclination will mean that no-one north of the latitude ofthe extreme south of theChannel Isles will be able toQS° it. Pilot Brian DuffyN5WQW will operate
In his first new -look column, Pat Gowen G3IOR has news on theAmerican Space Shuttle, coming satellites and schedules.
145.550MHz f.m. voice andpacket radio.
Coming Satellites
Eleven new OSCARsatellites are either soon tobe launched or are nowunder construction withlaunches planned betweennow and 1996. These are:
1. RS -15 from AMSAT-UA,due for launch on a non -fixed date between lateFebruary and early April 1993into a 2300km 67° inclinationorbit. It will have an orbitalperiod of two hours 14minutes and an increment of33.5° west per orbit.
Dave Rowan G4CUO hascalculated that we shall seeseven or eight passes perday, each lasting up to 32minutes. A real DXCC getterthis!
Dave ascertains that wein the UK will be able tomake QSOs out to KL7, all USstates W1 -WO (sadly notKH6), all VE1 to VE8, XE, TG,YS, YN, TI, TI9, HP, all theCaribbean, HKO, HK, HC, OA,CP, ZP, PY to Sao Paulo, PYO,ZD7, ZD8, all ZS, S8, 7P, 306,5R, FR, 307, 3B6, S7, VQ9, 8Q,VU, 4S, YB, 9V, 9M2, 9M4,9M8, V85, DU, CR9, XX9, VS6,BY, BV, JR6, JA, HL, BY9, JA9and UAO, and, of course, allpoints between!
2. ARSENE from France,going aloft with ASTRA-1-Con the ARIANE V-58 missiondue for launch on 20 April1993.
3. UNAMSAT-1 fromAMSAT-XE of Mexico, whichhas had its launchpostponed, but should be upand active soon.
4. CT-UoSAT by thePortuguese AMSAT Group,in combination launch withKITSAT-B and ITAMSAT-1,due in September.
5.1TAMSAT from AMSAT-Italy. This launch into amicrosat-type orbit will flywith the big SPOT -III and theamateur radio KITSAT-B plusthe above PortugueseUniversity AMSAT createdCT-UoSAT pair, in lateSeptember 1993.
The ITAMSAT isstructurally and digitallyidentical to the existingMicroSats, and will be
compatible with existingdigital communicationssoftware, supporting 1200and 9600bps modulation. Thefour uplinks will be on145.875, .900, .925 and.950MHz and the pair ofdownlinks on 435.760 and435.810MHz.
6. Phase -3D fromAMSAT-DL, NA andinternational support, withlaunch plans and details assupplied in past columns.More information will becoming soon!
7. TECHSAT from Israel.8. SUNSAT from AMSAT-
South Africa.9. SEDSAT-1 from the
University of Alabama.10. KITSAT-B, very similar
to KITSAT-OSCAR-24, withthe ARIANE SPOT -3September 1993 launchgiven above.
11. HUTSAT from theFinnish AMSAT-OH Group.
Whilst last month I gavesome of the details ofTECHSAT, HUTSAT, RS -15
and UNAMSAT, I shall verysoon be covering ARSENE.As the time of placing theother spacecraft into orbitapproaches and as the fulltechnical specifications,needs and operationalrequirements becomeknown, I shall be givingreaders full details in thiscolumn. For sure, the nexttwo to three years will be avery exciting time for OSCARsatellite users.
Attitude Changes
The Sun makes acomplete orbit of the Earthand the satellite path overthe course of a year, so theOSCAR -13 attitude schedulegives a familiar bi-annualrhythm. In previous years theorientation of the Sun's orbitwith respect to the satellite'sorbit has been relativelybenign, with poorpresentations being short-lived. Through 1993 however,the orbits are the leastfavourably inclined possible,so some unfamiliarstrategies are needed tocompensate, as lots ofeclipses by both earth andSun can be predicted. Theseare reflected in the
schedules below.James Miller G3RUH
provides the followingprovisional plans he hascalculated for OSCAR -13operations in 1993. He pointsout that the mode schedulesare dictated by the satelliteattitude, and this isestablished according to theSun position as seen by thesatellite.
Mode Schedules
Until February 8, OSCAR -13 was in Mode B onlythroughout the entire orbit,with it's attitude to the sunchanging from 130/0 in mid -December 1992 to 150/0 on18 January 1993. The omni-directional antenna wasthen used from MA 170 toMA 15. Due to eclipses, thetransponder will continue tobe commanded off betweenMean Anomaly 170 to 256from January 28 to March 4.
From February 8 toMarch 8 the scheduleplanned is:
Mode B: MA 0 to MA 40Mode S: MA 40 to MA 50
S transponder off, B on.Mode LS: MA 50 to MA
55 S beacon and Ltransponder on.
Mode JL: MA 55 to MA70 Alon/Alat 150/0
Mode B: MA 70 to MA256
Omnis: MA 170 to MA 15On March 8 the attitude
will move to 180/0. It isrequested that users don'tuplink to the B transponderbetween Mean Anomaly 40and 50, otherwiseinterference is given to theshort-lived Mode S period.
From March 8 to May 10the plan is for:
Mode B: MA 0 to MA 120Mode S: MA 120 to MA
130 S transponder on, B offMode LS: MA 130 to MA
135 S beacon + Ltransponder
Mode JL: MA 135 to MA150 Alon/Alat 180/0
Mode B: MA 150 to MA256.
More news of what'shappening in orbit next time.
50 Practical Wireless, March 1993
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Practical Wireless, March 1993 51
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SPECIAL OFFER7 Nights for
£497.50 !!!PRACTICAL WIRELESS is pleased to announce avery special offer for its trip to Dayton in April 1993.For anyone who is willing to pay now, we will give you 7 nights inDayton for less than we charged last year for 5! We can only do this becausethe airline has a limited number of reduced price seats available and they are lettingthem go at a silly price to anyone who pays now.If you're interested in going to the best radio show in the world and you think you'll be able to pay almost immediately,contact me to find out how you can take advantage of our lowest price ever.
During office hours you can call on 071-731 6222, fax on 071-384 1031 or you could write to Dayton Offer, PO Box 948,London SW6 2DX, but please remember, the limited number of seats at this price will only be available to readers whocan pay now.
Roger Hall G4TNT
Practical Wireless is a pw publishing ltd. publicationArrowsmith Court, Station Approach, Broadstone, Dorset BH18 8PV1T.
Tel: (0202) 659910 Fax: (0202) 659950
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NORBRECKAN
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Over 100 trade stands* Club stands* Bring & Buy stand* Amateur Computer stands* RSGB stand and book stall* Construction competition* Organised by over 50 clubs* Facilities for the disabled* Free car parking* Overnight accommodation atreduced rates - contact hotel
Admission £1.50 (OAP's £1, under 14's free)
Exhibition Manager :Peter Denton, G6CGF, 051-630-5790
52 Practical Wireless, March 1993
Feature
The oceans andradio have beentogether for almosta century. MikeHarris GOHOC,explains a few of thepracticalities oftaking radioequipment to sea.The informationshould also proveuseful to short wavelisteners.
Fig.1: Hoisting atemporary antenna. Atsea, good longdistance contacts arepossible on low powerand without a greatdeal of expensiveequipment. Antennaarrangements areoften the criticalfactor, though in thespirit of amateur radio,a little trial and errorexperimental work, isthe key to success.
Many of Marconi's experiments were carried out atsea. Today, by international agreement, variousfrequencies (eg 2.182MHz, 156.8MHz) have beenreserved specifically for distress or urgent messages.
Other frequencies are for use by ships andcoastal stations calls. However, there are noallocated frequencies for everyday informal use.
Hand-held At Sea
A hand-held radio is the easiest kind oftransceiver to take to sea, needing no additionalantenna or power supply. Precautions to keep thesystem dry need to be made, and probably theeasiest way of doing this is to enclose it in a heavypolythene bag.
These bags, Aquasacs, are available specificallyfor hand-held radios, cameras or just documents.The material is transparent and flexible, so mostcontrols can be operated without uncovering theradio. Fully sealed and containing air, should thebag fall into the water, there's a good chance it willfloat.
If you have ever been put off using 27MHz CBradio for various reasons, at sea it comes as apleasant surprise. Away from large populationcentres, it becomes much quieter and more pleasantto use.
Maritime Mobile
Since the amateur maritime mobile licence hasbeen incorporated into the amateur licence, many
MaritimeMobileAmateurRadio All AtSea
amatuers now use 'NM' after their callsigns. TheCEPT agreement with most European countries, hasremoved many of the obstacles to using amateurradio on holidays afloat.
On long distance world cruisers, the benefits ofamateur radio are well known. Most of us though,have to make do with more modest horizons.
There are the amateur maritime nets, operatingmainly on sections of the 7, 14 and 21MHz bands.These provide a marine radio meeting place. Forthose using it, there is a chance to give theirpositions, or to discuss weather reports, or find outhow friends are doing.
Often these nets start when a small group of`/MMs' meet regularly via radio, as a way ofpassing time on long ocean trips. As more join thelist, a net has been formed.
The arrangement can of course collapse equallyquickly. This makes it difficult to give acomprehensive listing of all nets operating at anyparticular time.
A few nets have withstood the test of time,having been in existence for 20 years or more. Somenets are keen to receive calls from anyone with aninterest in marine activities, regardless of whetherthey are sea or land based.
However, some nets have particular times whenthey listen out for emergency traffic to or fromstations at sea. So please listen out first and get toknow the form before calling in.
Continued on page 55
Practical Wireless, March 1993 53
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FRIEDRICHSHAFENVisit Europe's biggest radio show for just £249.75Our first coach trip to Friedrichshafen this year was so successful that we are repeating itagain next year. Now you can take part and enjoy four nights at the best hotel inFriedrichshafen, a 3 day ticket to the show and free excursions to the Black Forest.
Every year Friedrichshafen hosts Europe's largest amateur radio show and our reasonably priced trip willlet you to travel there in comfort on a luxury coach (equipped with toilet, coffee machine and video), stayin a quality hotel and visit the Black Forest. We'll pick up passengers from Victoria Coach Station early inthe morning on Thursday the 24th of June and then drive to Dover and catch one of the first ferriesacross. We'll arrive in Friedrichshafen late that evening (no overnight travel!) and then spend 4 nights atthe Buchorner hof Hotel. It is worth mentioning that the rooms in this hotel are doubles, that is really doubles nottwins - they have double beds. This means that ours trip is more suitable for couples, so to encourage wivesand/or girlfriends to come along there are a couple of day excursions on the Friday and Saturday.
The complete trip - coach travel, ferries, all tolls,4 nights accommodation (with breakfast andevening meal) and excursions - costs £249.75
(based on two people sharing) and there will be afew single rooms available for a supplement.
It will help 1110 with booking rooms if you can let inc know as soon as possible if you areseriously interested in going as so few places arc available and last year we had a waitinglist. If you want to know more you can usually contact Roger Hall G4TNT on071 731 6222 during office hours or by writing to me at P.O. Box 948 London SW6 2DS.
practical
Practical Wireless is a pw publishing ltd. publicationArrowsmith Court, Station Approach, Broadstone, Dorset BH18 8PW
Tel: 0202 659910 Fax: 0202 659950
54 Practical Wireless, March 1993
Fig. 2: My portable QRP rig. I use a Sony2001D receiver with a Howes kit
transmitter. The box also contains a 12Vdry -fit battery and has room for a
collapsible whip antenna and YaesuFT23R hand-held.
Fig. 3: Using acombination of
wind and sunpower to chargeup the batteries.The wind -driven
charge is aspecially
strengthenedversion of the
Rutland'Windcharger'.
Fig. 4: Portablecomputing. In
addition to packetradio, the KAMgives access toutility stations
broadcastingRTTY, c.w., FAX
(not too clear withthe computer
shown here) andAMTOR/SITOR
codes. It is worthremembering that
NAVTEX(navigational and
weatherinformation),broadcast by
stationsthroughout the
world on 518kHz,can be decoded in
FEC AMTOR orLAMTOR
(Listening modeAMTOR).
QSL Cards
I've heard that `/MM' stations never send QSLcards, though I know of many that do. This view hassome truth in it, so I'd better explain why. I knowsome amateurs value QSL cards highly, and ifpossible, I try to send them direct to those requestingthem. But as I've precious little space to spare, Idon't collect them myself.
Moving home frequently, makes receivingnormal mail difficult, let alone QSL cards via thebureau. So, sending cards may not always be asstraightforward as it seems.
Imagine a QSO made whilst at sea. Do I seal it ina bottle, before tossing it overboard? Or do I waituntil reaching terra firma? In some landfalls, a trip tothe post office might involve a long hike inland, ifthere is a post office at all.
Computers Aboard
When computers came in big boxes, withseparate monitors needing mains power, the idea ofinstalling one aboard a small boat was regarded asjust plain silly. Now we have laptop, notebook orpocket computers with very low power requirements.
From navigation and inventory control toproviding amusements for the crew, it's becomingincreasingly obvious that computers have a veryimportant part to play in small boats. Of course, theycan also be useful in radio communications.
With access to stations broadcasting FAX,weather and navigational information, a computer(with radio and decoder) can be extraordinarilyuseful at sea. The ability to receive detailed weatherinformation is obviously important. A multimodedecoder like a Kantronics KAM, an AEA PK-232 oran MR. gives packet radio capability as well.
Packet Stations
Land -based packet stations often keep theirequipment running continuously, enabling others toleave messages or relaying calls to more distantstations. At sea, radios and computers often haveother pressing tasks to perform, and power is limited.So this type of operation is seldom possible. Nonethe less, packet radio is an extremely versatile modeand one that `/MMs' should consider using moreoften.
I like getting to know people in locations I amvisiting. Fortunately, most islands have thrivingamateur communities. Last year, when visiting theCanaries, a short message, left on the club BBS,brought an introduction to a group of friends I wouldotherwise have missed.
Very few islanders spoke English, and my abilitywith Spanish is still at the survival stage! Real timeQS0s would have been hard going for both sides.Packet, on the other hand, isn't nearly so immediate.Messages on a BBS give both sides time to look upphrases, or to ask their friends.
I haven't seen packet radio used this way, butimagine a bulletin board which 'NM' stations couldaccess, reporting their position, weather conditions,skeds for contacting friends and any other generallyuseful information. Surely there must be bulletinboards set up for handling marine traffic somewhere?If readers know of such facilities, I would be verypleased to hear from them.
Antennas On Boats
Whip antennas for v.h.f and u.h.f. are quite small,and relatively easy to mount on boats. However, it'sworth bearing in mind that items sold for land -mobile use may be made from materials unsuited for
Practical Wireless, March 1993 55
use at sea.Extra care must be taken to exclude moisture
from connections and cables. Electrolytic corrosionis a serious problem.
Copper, brass and stainless steel items oftensurvive quite well in company with each other. Butif possible, avoid bolting them directly to anythingmade from aluminium.
Use plastics material sleeving and washers onall bolts. An insulating gasket between dissimilarmetal parts will also help. It might also be worthusing nylon nuts and bolts and all -plasticscomponents if they're available
Operation at h.f. generally demands a largerantenna. Because space on boats is always limited,beams and quads are usually out of the question.Fortunately, there are plenty of other types ofantenna to experiment with.
On boats where there isn't a mast to suspend along wire, whip antennas are often used. Even asimple G -whip can be quite effective, though a goodr.f. ground is necessary for best results.
The sea itself provides an excellent r.f. ground.On metal skinned boats, a sound connection to thehull should work. Wooden or fibreglass hulls need alittle more thought.
A large copper plate or one of the smaller,purpose made earthing plates (e.g. Dyna plate),bolted to the outside of the hull can be the answer. Itmay be sufficient to lay a large sheet of copperagainst the inside surface of the hull. This providesa capacitive connection to the sea.
In general, the simplest types of antennas areoften the most successful. This is probably thereason why a good many `/MM' operators usenothing more exotic than a wire dipole. Whenstored, dipoles take up little room in the luggage andthey can be hoisted from the mast as a quicktemporary antenna. They can be used on quite smallboats, though activities may be restricted to times atanchor or using a motor rather than sailing.
On sailing boats its not always easy to find anantenna site away from metal rigging and masts.The sailing rig has to be take priority.
But when sails are not in the way, a half -wavedipole hoisted from the mast head (Fig. la) can bemost effective. Try to feed the centre point as closeto a right angle as possible. Even the arrangement inFig. lb, where the dipole is hoisted from a flaghalyard, has often been found to work well.
The arrangement of Fig. lc, would workeffectively only if the mast is made of wood orcomposite material.
Mobile Dinghy
I'm usually not very successful at fishing, so it'snot often I spend Sunday mornings mobile in adinghy. The location was the bay of Gibraltar with aslightly lumpy sea. I was just drifting between 'therock' and the Spanish border. A bright clear day andexcept, for a small Spanish fishing boat a mile or soaway, I was alone.
It was an ideal time, so I thought, to try out thenew whip antenna I had to put together for a low
power, 14MHz c.w. transmitter I take on holidays orthe occasional trip abroad. I normally manage tohoist a temporary half wave dipole fromsomewhere, but a whip antenna would give me thechance to operate from awkward locations like my2.5m (8ft) dinghy.
The station consists of a Howes MTX20*transmitter, a Sony 2001D receiver and arechargeable battery pack.
To provide protection from the elements, I builta waterproof wooden case to enclose the variousparts. In addition, I use the receiver inside anAquasac.
Ground Plane
Given the good ground plane that the sea canprovide, low power h.f. operation can often producesurprisingly good results. So, after taping theantenna securely to the mast and tossing the metalgrounding plate overboard, I was ready.
After calling unsuccessfully for a time, andfinding 14MHz noisier than usual, I began to settleto the idea that I had chosen the wrong day. Just as Ibegan to think that fishing wasn't such a bad ideaafter all, a station in London replied to my call.Then another in the Canaries and a few more, andthings began to look a little brighter.
I have to admit that the signal reports werenothing to write home about, but I was pleased seethat the system worked under marginal conditions.One station described the signal as sounding a littlewatery!
Could it be that the odd wave had got into theset? I think that it's more likely the cause wasfeedback. I was having problems matching theantenna to the transmitter output impedance. Iwould deal with later.
A more pressing problem appeared, I'd driftedinto a collection of fishing net marker buoys. Thepeople in the Spanish fishing boat I'd noticedearlier, were now taking a suspicious interest in myactivities.
Unwilling, not to mention unable, to explain,that I wasn't after their catch, I set off home to makethe modifications on the whip antenna.
PW
C. M. Howes Communications, Eydon, Daventry, Northants NN11 6PT. Tel: (0327) 60178.
Further reading:A Guide to Small Boat Radio Mike Harris - Published by Adlard Coles 1991.
Fig. 5: Atypicalcommercialmarine bands.s.btransceiveraboard alarge modernyacht.
For a list of a fewknown maritimenets, send ans.s.a.e. to theeditorial address.Please mark theenvelope 'maritimenets'.
The February issue of Short Wave Magazine has articles on Maritime Distress Messages and LongRange Maritime Services. Another article shows you how to interpret Facsimile Weather Maps.
56 Practical Wireless, March 1993
PETER SHOR E
Practical Wireless,
Iwas 11 -years old when Ifirst bepme interestedin short wave radiolistening. The spurprayed to be a magazine
which my parents hadpicked up at an exhibitionthey had visited: it was acopy of Moscow Newswhich listed the times thatRadio Moscow's Englishprogrammes for GreatBritain and Ireland could bereceived, and on whichmetre bands.
The radio in the kitchen -a Roberts set - had shortwave and so, at theappointed hour, I tunedacross the bands and, sureenough, there was Moscowin English. It was quite athrill to know that I waslistening to a broadcast fromseveral thousand milesaway, from what, to an 11year old, was a very distantand unknown land.
It was not long before Idiscovered that otherstations were audible. Iquickly found Radio CanadaInternational and the Voiceof America and I started towrite to many of theprogrammes I heard. Thethrill of receiving letters fromall over the world, as well ascopious amounts ofpropaganda from the East,was equally as good ascatching a station for thefirst time! My sister wasquite pleased, too, with thestamps from hither andthither.
The Roberts set was notideally suited to DXing andmy parents invested in aRussian built Vega Selenawith umpteen differentbands and a noisy inbuiltmains transformer. It soonstarted to earn its keep and Idiscovered more and moreabout the workings of shortwave. But even the Vega didnot keep me satisfied and soI started to save my penniesand scan advertisements forsecond-hand equipmenthere in Practical Wireless.
I was soon the proudowner of a nearly newcommunications receivercomplete with digitalreadout, continuous shortwave coverage, variablebandwidth, b.f.o. and so on.
March 1993
Introducing his new -look column, Peter looks back at his earlydays in the hobby, and provides some good advice.
After that I did not look back.The point which I am
trying to make - and I hopethat I am doing it withoutboring you with a pottedbiography - is that if you arejust starting out listening tothe international broadcastbands you do notnecessarily have to buy thelatest, most sophisticatedand therefore perhaps mostexpensive piece of kit on themarket. It is quite possible tostart short wave listeningwith basic equipment withwhich you will have just asmuch fun whilst gainingexperience, and from thenon move up to betterreceivers as your interestdevelops.
If you are going to huntfor a second-hand piece ofequipment, do bear in mindsome golden rules. If you arebuying from a shop, see ifthey will offer some sort ofguarantee. After all, you donot want to make a capitalinvestment, only to see theradio pack up after a matterof weeks.
If you are buyingprivately, ask for the reasonfor the sale. Is it genuine -someone moving up to newequipment, giving upaltogether, or trying to off-load a piece of junk. And donot be afraid to haggle witha private seller, or even inthis day and age a shopselling second-hand gear.
Good luck, and if youmanage to acquire a goodpiece of nearly new shortwave radio equipment at areasonable price, pleasedrop me a line here at PW.I'd be delighted to hear fromyou and to pass on any tipsyou may have to the rest ofour readers.
Meanwhile, you willwant something to listen to,so here's some frequencyinformation from around theworld.
Europe
Radio Vilnius now hasEnglish daily at 2000 on twoshort wave frequencies of9.71 and 9.675MHz and onmedium wave on 666kHz.There is also a transmissionat 0000 on 17.69, 17.605 and
7.15MHz.Radio Norway
International's Englishservice was cut in half at theend of January. The stationhad carried Englishprogrammes on bothSaturday and Sunday, butnow only the Sundaytransmissions remain. Thisfollows a withdrawal offunding by the NorwegianForeign Ministry for theEnglish service.
Radio Sweden inStockholm has lost half anhour of its one -hourtransmission at 2130GMT.The portion from 2200 until2230 was carried exclusivelyon satellite, but budgetarycut -backs mean that fundingcould no longer beguaranteed for this extraEuropean -only service. The2130 transmission remainson the air for 30 minutes on6.065 and 1.179MHz and onthe Astra satellite.
Radio UkraineInternational broadcasts inEnglish at 2200 for an houron 15.385, 9.71, 7.24, 7.195,6.02, 6.01 and 4.825MHz andthen again at 0100 on 10.344(in upper sideband), 9.86,9.75, 9.71, 7.24, 7.195, 7.18,6.145, 6.08, 6.07, 6.02, 6.01and 4.825MHz.
Africa And TheMiddle East
Radio Iraq Internationalhas English services at 2200until 2400, directed to Europeon 15.21MHz and to EastAsia at 1400 to 1700 on13.68MHz.
From the Sudanese cityof Omdurman comeinternational services of theSudan BroadcastingService's Radio Omdurman.The station transmits to
Sony ICF 2001D.
Europe, Africa and theMiddle East in English at1800 on either 9.17, 9.18 or9.18MHz. The transmissionlasts 60 minutes. It ispreceded at 1700 by Frenchon the same channels.
The TRT's Voice ofTurkey in Ankara is on the airin English to Europe at 2000for an hour on 9.445MHz andat 2200, also for an hour, on11.895. The North AmericanService opens at 2200 on9.445 with a repeat at 0300on the same channel.
Asia And ThePacific
There is a brand newEnglish language service totry for from one of the formerSoviet republics. AzerbaijaniRadio in Baku is nowreported to be operating inEnglish every day at 1700 for60 minutes in the 49m bandon 6.175MHz - unfortunatelythe same channel as RadioFrance International'sEuropean service. However,do try and see whether thisnew station is audible inyour part of the world.
The Americas
Radio Havana Cubabroadcasts from theCaribbean island to Europeat 2100 on 17.705MHz.Spanish, also heard at 2100,beamed to Europe andAfrica, is carried on 17.77,15.22 and on 13.66MHz, thelast one in upper sidebandmode.
Cheerio for this time.Keep listening!
END57
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There will be trade stands, RSGB Morse tests, and lectures. You'll also have achance to meet other CW enthusiasts!
The Morse Festival hosted by the school Radio Society GORSC, is to be held atClayesmore School between Shaftesbury and Blandford in Dorset. The Festival runs
from 10am Saturday to mid -day on the Sunday. Come for the day, or stay for theweekend. Overnight accommodation and food at an inclusive reasonable price isavailable at the school.
Full details are included in the Morse Festival information pack, which is availableby sending an A4 stamped addressed envelope to 'Clayesmore Morse FestivalWeekend', Clayesmore School, lwerne Minster, Blandford, Dorset Di 1 I 8PH.
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58 Practical Wireless, March 1993
R 0 G E R CO OK E G 3 L DI
From the German groupthat brought you theBaycomm package, thisis Mini-Pac. This handylittle 'plug' is really acomplete v.h.f. t.n.c. Theminiature surfacemounted componentsa standard r.f. modare on the smallAll that is needpacket operasoftwarecommunicpackage ruIBM PC or clone.more information aboutthis cheap entry topaket radio, contactSiskin Electronics on(0703)207587.
ave RobertsG8KBB, has sentme details of thelatest release ofhis computer
program, TheNet. Dave is avery active member ofEADG, East Anglian DataGroup, and is involved innetworking as a profession.He is also very keen onTCP/IP and is at presentinvolved in setting up a64kbaud s.h.f. link.
Latest Release
The latest releaseincorporates: an IP router,the ability to remotely set thenode alias and the ability tolisten for three additionalaliases and automaticallyinvoke the BBS, Host orDXCluster commands onuplink.
Additional nodebroadcast controls exist inthe form of selective portcontrol over 'hash' nodebroadcasting. The word'quit' is introduced as analias for 'bye', and a UIcommand allows arbitrary UIframes to be sent for use in,for example, MAILnotifications. In the routeslist, callsigns may optionallybe shown as alias andcallsign.
A menu drivenwindowing patch utility, withcontext sensitive help is alsoincluded. The previousreleases introduced thefollowing:
Access control listcapabilities.
Multi-user conferencing(TALK command).
CWID keyer.
This month, Roger Cooke G3LDI, brings you news of a newpiece of software, and some more general information withchanges of the country and continent designators.
Better Sysopauthentication.
MHeard list showingcallsigns, packets heard andtime since last heard.
Closedown command toremotely shut down thenode.
DXCluster command thatoperates like the BBS / Hostcommands.
BText command to setthe Nodes' beacon message.
Ability to enable ordisable any command.
Improved commandprompting with only validcommands shown.
KISS as an alternative tothe crosslink protocol.
Hardware handshakecontrolled host modeoperation.
MODE command forconfiguring additionalparameters.
BBS command to autoconnect to a remote BBS.
HOST command to autoconnect to another BBS orHOST.
BYE command todisconnect.
STATS command todisplay internal statistics.
MANAGER command forsystem manager access.
AUDIT command to setsystem audit levels.
Bug fixes (e.g. infomessages too long).
Changes to the Nodescommand.
An improved nodesbroadcast algorithm for thecrosslink port.
Split port nodesbroadcast intervals.
Ability to enable/disablenodes broadcasts on eachport.
Ca apologises nicely ifdisabled.
Most escape commandshave been replaced
with MODEparameters.
Beaconmessages can be
digipeated.CALIBRATE
command for remotechecking of TX
deviation.LINKS command to
show current level twolinks.
Configuration of thebeacon period.
Auto routing of'connect' to either BBS,DXCluster or HOST.
Remote dump of entireneighbour lists for all nodes.
Hardware requirementsare fairly simple, thesoftware runs in a Z80 basedTNC or similar clone such asthe BSX2.
Installation instructionsare included in a file on thedisk. But essentially, all thatis needed is a single piece ofwire from pin eight of themodem disconnect header,to pin one of the Eprom. TheEprom needed is a 27512,rather than the normal 27256of a normal TNC2. Pin one ofthe Eprom is bent out fromthe socket, and connectedas described above.
The IPRouter
The IP Router co -existsin the node with the othersoftware. It is connected tothe Level 2 and Level 3(netrom) protocol machines,and is managed from theLevel 7 switch. It will acceptdata from Level 2Datagrams, Virtual Circuitsor NOS protocol extendednetrom frames. It will outputto these three depending onthe setting of the IP routeand ARP tables.
The router supports theIP options of NOS and alsodoes IP fragmentation. Level2 segmentation is notsupported.
Single Disk
The software is suppliedon a single 720K 3.5 inch diskand comes complete with auser manual, detailing theinstallation, commandstructure and an overview ofthe operation. If you areinterested, you can obtain acopy by sending the usualrequest, together with a disk,mailer, plus enough returnpostage to:
Dave Roberts G8KBB, 7Rownhayes Close, IpswichIP2 9SX.
Dave also welcomes anysuggestions for change andthese can be sent to thesame address, or to G8KBB
GB7MXM.
Operation inHungary
I've had a bulletin sent tome by HA5DI, but space hasprevented me from using it,but an A5 -sized s.s.a.e. tothe editorial offices will getyou the information. Pleasemark the envelope'Hungarian Packet Stations'
ContinentDesignators
Just enough room tosqueeze in information ofproposed continentaldesignations. The followingwere suggested by TomW3IWI, in a paper presentedby him.
Hopefully they willbecome adopted world-wideeventually, and I wouldsuggest that you use themwhen addressing mail.Hopefully sysops in thiscountry will adjust theirforward files accordingly.
The code NOAMreplaces NA for NOrthAMerica and Canada, whileCEAM is added for CEntralAMerica, including Mexicoand Panama. For theCARiBean Islands including9Y, the code CARB is added.
Further south, SOAMreplaces SA for SOuthAMerica, over the Atlantic,AFRI replaces AF for AFRIca.For Europe EURO replacesthe older EU, MDLE is addedfor the MIDdLE Eastincluding 5B4, 4X, HZ, JY etc.
For Asia, ASIA replacesAS, to include the callsignsYB and 9M. North of theequator in the Pacific, NPACreplaces OC for the PACificislands, while south of theequator, SPAC replaces OCfor the South PACific.
Finally added codes are,INDI for the INDIan Oceanislands, and ANTR forANTaRctica.
That's about it for thismonth. Don't forget that'Packet Panorama' will be inPWevery month as fromnow.
73 and happy packetingde Roger, G3LDI (4) GB7LDI.
E N D
Practical Wireless, March 1993 59
DAVID BUTLER G4 ASR
Fig. 1: DavidButler's c.w.contacts made bythe auroral mode(see text).
Hi and welcome tothe new style v.h.f.column! I havenews of excellenttropo openings, a
number of auroras, someamazing meteor scattercontacts and a report aboutthe recent Quadrantidsmeteor shower. There's alsoinformation about the 50MHzband, new DXCC countries,details of up-and-comingv.h.f. meetings and the usualsolar data, propagationforecast and contestcalendar.
Tropo
Conditions via the tropopropagation mode duringDecember were generallypoor, although there wereenhanced periods notably onDecember 14 and betweenDecember 26-28 whentropospheric contacts couldbe made with stations up to1000km distant.
The best direction from
the UK on December 14 wasin a south-easterly directionwith stations such asHB9HLI (JN37), HB9SAX(JN36), HB9SNR (JN36),0E2HFO (JN67), 0E5MKN(JN78), OE5VHL (JN68) and0E5XJM (JN68) beingworked on the 144, 430MHzand 1296MHz bands.
Conditions to the eastwere also good with RichardGardner G4WKN (1092)
David Butler G4ASR introduces his new look column, andlooks into tropo, aurora and everything else of interest to thev.h.f. operator.
reporting many s.s.b. andc.w. contacts includingSP3DRT (J091) on the144MHz band. Variousbeacons were also reportedsuch as HB9HB(144.865MHz), HB9F(432.984MHz) and OKOEAJ(432.938MHz).
The period betweenDecember 26-28 producedmuch traffic on all bands,especially during theafternoons when itcoincided with the RSGBChristmas v.h.f. contest. Allbands above 144MHz hadpropagation to a wide areaof continental Europeincluding F, ON, PA, DL.Stations in HB9 andGermans close to the SPborder were also worked.
Conditions were alsogood within the UK andmany stations in southernEngland reported workingGM3P01 (1088) on theOrkney Islands. Towards theend of the period the movingtropo had swung aroundtowards Scandinavia,enabling many contacts tobe made with stations in OZ,LA and SM.
It was interesting that, attimes, stations could beworked on tropo or aurora(see later) depending onwhich way you pointed thebeam! Another point ofinterest was that the EA1VHFbeacon (144.867MHz)located on the north coast ofSpain (IN53) was audibleover much of England andWales for nearly a week,sometimes peaking 599, butwith very little amateuractivity noted.
Paul Brad beer GM7GUC,kept a close eye on theweather maps over theChristmas period. Havingdecided that conditionslooked good for DX, he wentout on December 27 tooperate portable from EastLomond Hill (1086).
Using an Icom IC275Hand a Cushcraft 13 -elementYagi on the 144MHz band hemade 128 QSOs, only 10 ofwhich were with G -stations.Most of the contacts werelocated in DL, ON and PA,the best DX being DBOBIT(JN39) at 1012km and F1CYB
(JN17) at 1058km.On December 28, Paul
found that the bestpropagation was towardsScandinavia and nearly 40s.s.b. contacts were madewith stations in LA, OZ, SM,DL and PA with SM7MBG, inJ075, being rated the bestcontact.
Jim Smith GOOFE (1090)reports working F1ER (JNO3)on November 22 when it waspouring with rain, normallyan unlikely time to work longdistances. Jim mentions thathe has often noticed that ifwe are in a warm sector of adepression during wintertime with a strong ridge ofhigh pressure to the south,enhanced tropo conditionsto the south of France canresult. It's always worthwatching the weather map,even when the weather isunsettled.
Auroral Calendar
In last month's issue ofPW, I described an auroralcalendar and by using theexample shown I wonderedif an event would occur onDecember 20. Unfortunatelyit didn't, but there was onewhich occurred three daysearlier on December 17!
If you've made a copy ofthe calendar you might careto add in the following dateson which openingsoccurred; November 30,December 17, 28 and 29th.That's 58 auroral eventsrecorded in central Englandduring 1992.
If you live further norththen you should havenoticed more. However, ifyou live in southern Englandthen you probably heard nomore than 20 openings.
Conditions during 1992were not as good as inprevious years. Butnevertheless, a fair amountof DX could still be workedas indicated on the locatormap, Fig.1. It shows allauroral c.w. contacts madefrom my QTH (1081) during1992 on the 144MHz band,with stations in 110 squaresand 23 countries.
The openings onNovember 30 and December
17 were relatively weak withlittle DX being reported.Apart that is, from a fewstations such as LA1WFA(J049), OZ5IQ, OZ7AMG(J065), SLOCB (J089),SM5BSZ, SMSDIC (J089)and SK6KQ.
The event on December28 however was quiteinteresting, because itoccurred during the RSGBChristmas v.h.f. contest (asdid the opening on the 29th).The aurora was favourablylocated enabling UK stationsto work into the Balticstates.
Some of the DX thatcould be found on c.w.included LA1EKO (J016) onan oil platform in the NorthSea, SMs in call areas 4, 5, 6and 7, ES2XM (K028) andUZ2FWA (K004). The latterstation was particularlystrong (8 x 13 -element Yagisand 1.5kW) peaking 57A.
Meteor Contacts
What is probably one ofthe rarest meteor contactsto be made on the 144MHzband for some time mustsurely be that between thestations of David Law GOLBK11093) and JX7DFA (IQ50),located on Jan MayenIsland.
The contact, during theGeminids meteor shower onDecember 13, wascompleted in 20 minutes,with GOLBK receiving fivebursts and five pings withsignals at times peaking S8.The distance between thetwo stations was 1977kmand contacts were alsomade from JX7FDA withG4APA (in fact, the first G -contact), GMOHUO andGM4YXI.
The station of JX7DFA,operated by Per -EinarLA7DFA, consisted of 4 x 15 -element Yagis and a 70Wamplifier. Plans were wellunder way to become veryactive on e.m.e. (with 1kW),but unfortunately the entire144MHz antenna system anda 50MHz Yagi weredestroyed in severe gales onDecember 14.
The Earth has beenencountering the
60 Practical Wireless, March 1993
Good antennas - always the best pre -amp!The 144 and 430MHz system at the 0TH ofDKODW. Photo by GW8VHI.
Quadrantids meteor shower(January 3-4) every yearsince the year dot. But in1993 they seemed to havedecided to go walk -aboutand not appear!
Although the number ofbackground meteors rose, itwas fairly insignificant andconditions were generallyregarded as poor. A fair bitof activity was noticed onthe 50MHz band, but I can'tunderstand why all theactivity was centred on50.110MHz (the inter-continental DX -callingfrequency) and not on50.300MHz (s.s.b.) and50.350MHz (c.w.), the meteorscatter calling frequencies.
Yes, I know you mayhave heard me on .110 but Ididn't really want to bethere. Still, I did get S59AM(ex-YT3ET) and S59UN (ex-YU3ZV) for new ones!
In the November 1992issue of PW, I describedtests carried out in 1979/80with VE1ASJ via m.s. on the144MHz band, and wonderedif anyone would like tochallenge the record thisyear.
If you're thinking about aQSO partner, news hasreached me that MikeVE1 MQ is looking for well-equipped stations in westernEurope to participate intrans -atlantic tests. He usesa 17 -element Yagi and 170W(in my opinion far too QRP!)and can be contacted on0101 506 357 3035.
The 50MHz Band
Conditions duringDecember on the 50MHzband were very grim, withDX only being reported onfour days and three of those(December 17, 28, 29) were
due to auroras! A Sp -Eopening to Sweden andFinland occurred between1600-1700UTC on December21, but was missed by manyoperators.
Following the aurora onDecember 28, a number ofstations waiting for themidnight phase wererewarded with an Auroral -Eopening. This propagationmode is subtly different fromaurora and is more akin toSp -E. Signals are T9, eventhough the ionisationoriginates from auroralparticles, rather than solaruv radiation.
Signals were first heardby Neil Carr GOJHC (1084) at2230UTC who heard OHI Xpeaking 52. At midnight,G30IL 11091) reported theGB3LER beacon (Lerwick)putting in a very strong T9signal, and later between0100-0200UTC Peter G7ETZfound LA6VBA and LA9ZV.
Two Republics
On 1 January 1993, twoautonomous republics werecreated from the formerCzechoslovakia. Czech radioamateurs located in thestates of Bohemia andMoravia will continue to usethe old prefixes of OKI andOK2, but those situated inSlovakia who previouslyused the prefix OK3, will nowuse 0M3.
A new Society, theSlovak Amateur RadioAssociation (SARA), hasbeen formed and will providesimilar facilities to thatextended by the existingCzech Central Radio Club(CRCC). The DXCC status ofthese republics has not yetbeen announced, but Isuspect this will be a mere
formality when the ARRL DXAdvisory Committee nextmeet.
Tom CiepielowskiSPSCCC passes on the newsthat all licence class holdersin Poland were grantedaccess to the 50MHz bandfrom 15 January 1993. Theyare allowed to operatebetween 50-52MHz with 10Wof s.s.b. or c.w., and thereare no geographicalrestrictions. Tom expectsaround 100 stations to beactive by the summer Sp -Eseason.
VHF Convention
The RSGB's National VHFConvention is being held atits usual venue, SandownPark Racecourse, Surrey onSaturday 6 March, the doorsopening at 1030. In additionto the trade exhibition,specialist groups andequipment test facility, a fulllecture programme has beenarranged. Further details canbe obtained from myself on(0873) 87679.
The Martlesham RadioSociety are holding a v.h.f.round -table at the BTresearch laboratoriesMartlesham Heath, Suffolkon Sunday 28 March. Themeeting will include atechnical workshop,lectures, noise figure andother measurements and abring and buy stand. A p.c.will be running both theDL6WU antenna programand TCALC receiver front-end analysis program. Alsoon display will be all thetransverters featured in theVHF/UHF DX Handbook(ISBN 0-9520468-0-6). Pleasenote that the meeting isstrictly by invitation only.Tickets must be obtained inadvance from Malcolm BellG4CXT. His telephonenumber is (04731645533 (day)or (0473) 610073 (evening).The Nordic v.h.f. meeting isbeing held between June 11-14 at a QTH near Haslev,Denmark. The event willinclude a lecture programmeand of course will provide anideal opportunity to meetmany Scandinavian v.h.f.operators.
Indoor accommodationand food is being provided ata local Scout camp and willbe inexpensive but basic. I'mplanning to be at thismeeting and will havefurther details if you care tocontact me.
Looking ahead toSeptember and a reminderthat the largest v.h.f. meetingin Europe is being held inWeinheim, Germany (JN49),on September 17-19. Again, Ican give you more details ifrequired.
There was a increase in
geomagnetic activity duringthe last week of November,with three small M -typeflares occurring onNovember 22, an M4.4 flareon the 23rd and four M -typeflares, the biggest being anM2.6 on November 30. Anumber of brief short wavefade-outs (s.w.f.) occurredduring this period andauroral activity wasobserved on November 23and 30th.
During the first twoweeks of December, thequiet side of the sun was inview and very little solaractivity and no flares wererecorded. However, as theactive side of the sun rotatedinto view, the geomagneticfield became more unsettledand a sudden stormcommencement (s.s.c.) wasissued on December 17.
A disintegrating filamentcaused a magnetic storm tostart on December 27. Itcontinued until the 29th,creating auroral activity onDecember 28 and 29th.
Contests
In case you've forgotten,the last three 70MHzcumulative contests will takeplace on February 21, 28 andMarch 14. Each session runsbetween 1000-1200UTC. Inaddition to exchangingcallsigns, report and serialnumber, stations must alsogive locator and QTHinformation.
If you fancy a bit of key -bashing and conditions areright, you might like to enterthe German AGCW-DL430MHz contest, being heldon Saturday March 20,between 1900-2300UTC.Contestants can enter one ofthree sections relating to thetransmitter power; A = lessthan 3.5W, B = less than25W, C = more than 25Woutput.
Participating stations,who must only use the band432.010- 432.150MHz, shouldcall "CQ AGCW TEST" andexchange RST, serialnumber, power class andlocator, for example;599001/C/I081MX.
The RSGB MicrowaveCommittee have arrangedWinter cumulatives contestsfor bands above 2.3GHz totake place on SundayFebruary 28 and March 28.
The Nordic activitycontests will be heldbetween 1800-2200UTC onthe following Tuesday's:February 16 (Microwaves),February 23 (50MHz), March2 (144MHz) and March 9(430MHz).
Deadlines
As usual, I'll remind
you about deadlines.
Please send your
letters to reach me by
the end of the month at
the very latest. I
normally write up the
column around this
time.
Don't forget that I
can also receive
messages via packet
radio at my mailbox
GB7TCM or at my DX
cluster GB7DXC.
Photographs of
your shack, antennas
or any v.h.f. activity are
especially welcome.
Other pictorial items
such as QSL cards,
awards, certificates,
etc., are also required.
They will all be
returned to you.
E N D
Practical Wireless, March 1993 61
P AUL ESSER Y GW3K F E
O
Od
Chasing DX
Become a listener! InQSO, you must have areceiver tuned to histransmitter and vice versa.Otherwise no contact ispossible. First find whereyour man is transmitting;then find where he islistening.
By extensive listening toother people in pile-ups youget to know the right wayand - FAR more important -the wrong way! Example:some 25 years ago alicensed amateur showinghis rig to a couple of others,called an imaginary VK on7MHz around 2100Z andcompleted half of a c.w.contact.
The frequency at thestart was quiet but GRMgrew. Chuckling, to the pubfor a couple of hours. Whenthey got back, a great mobwere still calling theimaginary VK! Not one couldhave heard the VK, 'cos hejust wasn't there! However,no real DXer had beenfooled.
In a big pile-up, you canbe sure he won't be listeningwhere he is transmitting. Soyou must listen on twofrequencies; meaning a two-v.f.o. transceiver, or anoutboard v.f.o., or a secondreceiver, or even an old-time'separates' rig using tworeceivers. Know where he istransmitting and where he islistening and you've as goodas nailed him. Incidentally,for long odds, you've got hisdetails before your first call!
Low Power
any
I think that G-QRP Clubmembers come in two types,operating -wise. First comesthe guy with the low powerbut a first-class antennasystem. Secondly there arethe real masochists who liketo use low power and coupleit to a poor antenna!
The first type - G4BUE inflea -power mode forexample - can compete onnear level terms with the'Full Gallon' ops. He can puta signal anywhere in theworld when the bandpermits; the limit is set by
Paul Essery starts off his new -look column with some goodadvice, by advising you to listen!
how well the other chap cancopy.
Our second type is likeEric GOKRT (Worcester Park,Surrey). Eric runs a LakeDTR7 at 1W into a 1990s
W3EDPantenna; the 1930s originalran an 84ft top (26m),coupled to the 'wrong' endof the tank coil, against acounterpoise of givendimensions. He uses a singlequarter -wave counterpoiseand feeds it conventionally.To nail K8P0 in the CO WWCW contest was anachievement, but, as Ericsays, a major contest is agood time for him to find newcountries. As the DTR7 is a7MHz only rig, GOKRT knowshis band. Eric's set-up alsocovered all Europe, with acouple of LZs to add anothernew one on the band.
Another low -power waylover is Leighton SmartGWOLBI in Trelewis. The rigis a Yaesu FT747GX modifiedfor a maximum of 20W.Outside, 175ft (53m) of wire -just over the quarter -wavelength - covers 1.8MHz from9m high; a W3DZZ trapdipole at 8m does for 80 and40; sloping dipoles for14/18/21/28MHz and thesemanage to reach about 4m.
Leighton GWOLBI nailedthree Ws on sideband withjust 50mW. Outside that,KB1FK was raised on 1Wc.w. and KF4RP on sidebandwith 4.5W - he was running1kW and the QSO lasted 26minutes. On the awards side,DXCC QRP is now on thewall, with 40 countries
The QRPshack ofLieghtonGWOLBI.
worked on milliwatts.Ted G2HKU in Sheppey
tries 5W when the moodtakes him; on 28MHz c.w.5W made out with6W6/K3IPK and VP5P.
ContestsPrefixes AndExpeditions
The EA RTTY Contestcovers 3.5-30MHz, as perbandplans, 1600 Saturday to1600 Sunday, February 13-14.EAs send RST and 'PrefijoProvincial' of two letters.Others send RST and COZone number. Score, on14/21/28MHz, one point forown continent, two for othercontinents, on 3.5 and 7MHzthree and six; multipliersDXCC countries and SpanishProvinces on each band.Final score total QSO pointson all bands times totalmultipliers points on allbands. Logs mailed by April10 to EA RTTY CONTESTMANAGER, EA1MV, PO Box240, 09400 Aranda de Duero,Spain.
The CO WW WPX Phonedates are March 27-28, andc.w. May 29-30. Single-opsuse only 36 of the 48 hours.Off periods at least 60minutes in length and clearlymarked in the log.Categories, single -op singleband, single -op all -band; noform of 'DX alerting' allowed,multi -single, multi -multi.Low -power, as for single opbut less than 100W output(!).'QRP/p' output power notto exceed 5W; this categoryto indicate 'QRP/P' on results
sheet and indicate actualpower out for all claimedcontacts. QRP/p stationsonly compete with eachother. Exchange RS(T) plusserial number. Score:stations on differentcontinents count three on14/21/28MHz, six on1.8/3.5/7MHz; samecontinents one for14/21/28MHz, two for1.8/3.5/7MHz. Own countryno QSO points but OK formultiplier. The multiplier isthe number of differentprefixes worked. Final score,total QSO points timesmultiplier. Postmark date nolater than May 10 or July 10respectively, to WPXContest, Steve Bolia N8BJQ,4121 Gardenview Drive,Beavercreek OH 45431, USA.
The ARRL InternationalDX Contest has February 20-21 for c.w., March 6-7 forPhone. 1.8-30MHz,categories single -op singleor all -band. multi -op onetransmitter, multi -op twotransmitter, multi -multi.USANE send RS(T) plusstate/province. Others sendRS(T) plus power input(three digits). Outside USA,multiplier is sum ofstates/provinces worked perband. WNE, multiplier isDXCC countries each band.Mail deadline April 7 to ARRLDX Contest, 225 Main Street,Newington, CT 06111. BothARRL and CO contests havefirm disqualification rules.
The RSGB 7MHz c.w.Contest is from 1500zFebruary 27 to 0900zFebruary 28. UK stationssend RST plus county code,others RST plus serialnumbers. Logs by April 1 toSV Knowles G3UFY, 77Bensham Manor Road,Thornton Heath, Surrey CR77AF.
Note the OKI and OK2,Czech Republic are now OKand OL. OK3 is now Slovakiaand OM. No detail yet onDXCC status. The old Y2 -Y9calls are replaced by DL1-9ones.
About March 5, KingmanReef KH5K operation is likelyfor eight to nine days, withPalmyra in parallel.
San Andres, HKO ispromised between February
62 Practical Wireless, March 1993
H F B A N DS R E P OR T
27 -March 7. KB6GL andAA5AU will sign HKO/owncall.
The C6AGN Bahamasactivity from Green TurtleCay is set for March.
Reports
Rich GORKJ (and N7CXB)in Liskeard, has an R5antenna, an IC -725, fedthrough two low-pass filterswith a watt meter between.He has high-pass filters atthe video input and on theTV. Rich likes 28MHz f.m.,where the calling frequencyis 29.6MHz, QSYing to -usually - 29.350 for thecontact.
European f.m. simplexcontacts are best around0900-1100, with the UScontacts between 1300-1630GMT. Most interestingone in the crop possibly, wasEI7CV worked through theBoston repeater at29.620MHz; neither the El norRich could hear each otherdirect.
A new reporter is CliveGM3P01 in Deerness,Orkney, who uses 7MHz c.w.Clive found XX9TRF, BV2TA,A71AL/SP5EXA, HZ1AB,KP2A, VS6W0 and othersaround the six continents.
Ted G2HKU tried 1.8MHzfor GW4RPU and ON7BW onsideband, GM3P01 on thekey. On 3.5 a string of Ws,EA9LZ and DHOW; 7MHzagain Ws, EA9EA, UL7, U18;ZC4ST and UF6CFZ on10MHz, Ws and 9H4R on14MHz; Z21HQ, 6W6/K3IPK,VE7ZZ and Ws on 21MHz;and a stack of assorted DXon 28MHz
Don GM3JDR (Aukengill)works, c.w., the world onany band; around 0800/0900on 3.5MHz JAs and LUs.7MHz saw all the continentswith a good showing ofW6/7. 10MHz, ZA andVK6HD; 18MHz VP2V/KG6WI,21MHZ 9Y4VU, P40J andD44BC plus 28MHz with suchas 8R1K, P40s, 6V6U US1Uand 5NOHKJ plus of coursethe smaller fry.
The WARC bandspecialist Vince 9H1IP(M'Scala) on 24MHz hadTL8CK in November and inDecember came C9RJJ7Q7ZZ and XX9TNB. 18MHzin November was notablefor PYOTSN (Trindade Is),D2EL and others, withDecember for C31YA and7Q7TA. Lesser lights also ofcourse.
On 10MHz, Mike GOKDZfound VQ9AC, XW7F91E,KL7CYL and A71AL/SP5EXA -what a contrast the lattertwo make!
Favoured by JohnG3BDQ is 1.8MHz, withWODRL (Kansas, 0713z) asthe best among lots of DX.We'll tell you how he hearssuch stuff next time.
Finally, Don G3NOF(Yeovil) who notes that withwinter conditions the higherbands are dead by 1900.14MHz yielded a string ofJY40 stations VP8CGK inSouth Georgia and VQ9ACas pick of the crop for thistime.
Rich Weiss
Upham Down,Wodhorn 010..
P1.14 380
WAIL SX 26
Lox:- 10 70 SK
To Rodeo
Confwnung our DSO
At GMT on 19
Frio MHz Wenn
Yow &gnaw .11111 RST
Antenna TCVIT
/SE TPIK osi. Throat - Vie 8800
Listeners
Listeners are alsowelcome to report; tell uswhat you have to listen withand the best of the DX eachmonth.
Deadlines
Send your our reports tomy address please, to arriveby the beginning of eachmonth. 287 Heol-y-Coleg,Vaynor, Newtown, PowysSY16
'Bye now!
EN D
QSL card ofRich GORKJ.
fWstseff
NOE°14°1
the
,_r,en !coltel313ce
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rakingyour car abroad
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ON SALE 11th FEBRUARY 1993Practical Wireless, March 1993 63
Ron Ham starts his column off this time by taking aclose look at a reader's 1928 receiver.
I'm keying this month's vintagewireless chat while looking at thepicture, Fig. 1, of the inside of a1928 'Selecta' wireless receiver.This was kindly sent by Peter Jonesof Fownhope in Hereford.
Peter's photograph gives us achance to take a detailed look insidethis typical battery set of the late1920s era, and to mention in passinga few of the closely allied subjectsas they come to mind. Peter hasother interesting items in hiscollection that we can talk aboutnext time.
Dry Batteries
It appears from the internalstructure that this Selecta waspowered by two dry batteries.There's a high-tension (h.t.) batterywhich fitted along the bottom of thecabinet in the dedicated space belowthe speaker, and a grid -bias typewhich sat in that special large clip,centre right. There's also a 2V wetcell (low-tension), better known as arechargeable accumulator. The latterstood on the left, below what lookslike, a screened -grid valve.
Coloured wander plugs, oftenwith polarity tags on the leads.would have been used to connect theset to the required tappings on the9V grid -bias and the 90 or 120Vhigh-tension batteries. A pair ofspade -connectors (red and black)were used to hook around the twolarge terminals on the top of theaccumulator, Fig. 2. Depending onuse, the expected battery life wasabout 12 months for the grid -bias.four to six months for the h.t. andaround four days before theaccumulator needs recharging.
Most set owners had twoaccumulators, one in use while theother was at the local cycle orwireless shop, or garage, beingcharged. The average price forcharging was 6d (2.5p) andremained so through to the early1950s.
In those days, many people putanother 6d by each week, toward thecost of a new h.t., and their annual10 shillings (50p), wireless licence.In fact, a special container was madeto collect enough sixpenny coins tomeet the licence fee, which at onetime was seven shillings and sixpence (37.5p).
Fig. 1: Peter Jones 1928'Selecta' Receiver.
Replacement
Although, like many similar sets,the rear cover of the Select(' ishinged for easy accumulatorreplacement, this procedure wasalways a risky and messy business. 1say risky, because an accumulator,Fig. 2, (and there are still someabout), contains a large amount ofsulphuric acid and periodically needtopping -up with distilled water. Theacid level, illustrated by the dottedline in Fig. 2, is usually scribed onthe thick glass container.
WARNING, this acid isdangerous. If acid is spilt it willburn you and very quickly makeholes in your clothes or anythingelse that it touches.
I've heard of many table cloths.nearby carpets and curtains, if theset was near a window, that wentrotten through being dripped on. oraccidentally rubbed, by theaccumulator when it was changed. Ialso emphasised messy, becausefrom the shop's point of view, eachtime one was put on charge. the ventplug or 'stopper' (between theterminals at top of Fig. 2) had to beremoved to let the charging gasescape.
A full charge took about threedays and, as a result of theaccumulator 'gassing', a finecoating of liquid often covered theterminal area. At the end of thecharging period, this had to bewiped off and the terminal threadsgreased to prevent green corrosionsetting rapidly in.
Despite being a large diameter,such corrosion could solidly lock theterminal threads. Most accumulatorswere fitted with a wooden 'roller'type carrying handle by the makers(top Fig. 2). Some folk had a specialcarrying box made which fitted intheir bicycle basket. The user had to
Valveswalk or cycle to the charging plant,because it was illegal to take one ona bus. The reason being that evenone tiny drop of spilt acid could ruinthe whole seat.
Current Consumed
The amount of the currentconsumed in a set depends upon thetype of valves employed. I estimatethe total current taken by the fourvalves in Fig. 1, would be 600m/alow-tension and 10m/a high-tension.
Obviously, the set designer'schoice of valves in the late 1920swas limited, however, let's take alook at the basic power requirementsof a 'simple' wireless valve. This isa thermionic device referred to as atube in the United States, and a lampin some European countries.
The component parts within itsglass envelope are called electrodes.The part that 'lights up' is known asthe filament, in directly heatedvalves, Fig. 3, or the heater inindirectly heated valves, Fig. 4.With few exceptions, the former arefound in battery -operated receiversand the latter in sets run from themains.
Basically, for a valve to work, its'heating' arrangement emitselectrons which are attracted towarda relatively highly positive anode. Itis the heating element, like a torchbulb and the anode that consume thepower in a three electrode valve,known as a triode.
The filament in the directlyheated valve emits the electronswhich pass through a wire -mesh,called the grid. on their way towardthe anode. Fig. 3, 1 (left). Someearly text books refer to the anode asthe plate. which is logical, because ifyou take a look at a triode valve youwill see the filament in the centre,surrounded first by the wire -mesh
grid and then a solid metal plate(anode) as illustrated in Fig. 3 (left).
The electrodes are insulatedfrom each other inside the glassenvelope and connected by thinwires to specific pins on the valve -base. The theoretical drawing of atriode, as it would appear in a circuitdiagram, can be seen on the right inFig. 3.
The difference between directlyand indirectly heated valves is theadditional electrode known as acathode (K), Fig. 4. This is placed inthe centre of the valve between theheating element and the grid. In thiscase, it is the coating on the cathodethat emits the electrons and not theheating element.
All the heater does, is to keepthe cathode at its efficient workingtemperature. Although morecomplex valves have several grids. itis always the one nearest the cathodeor the filament that is called thecontrol -grid. The signal input pointin most circuits.
Valves & Components
Three triodes, like those in Fig.3, can be seen to the right of thetuning coil inside the Selecta, Fig. 1.One thing I spotted. was the metalliccoating coming off the fast valve inthe top right-hand compartment.
The coating acts as a screen tostop the valve detecting unwantedsignals. Note also the balancedarmature loudspeaker with amechanical 'tone' adjuster in thecentre of the magnet assembly. Theadjuster should be moved about halfa turn either way when the set isrunning to produce the best qualitysound. A distinct 'pop' should beheard when the setting is correct.
A torch bulb, seen between thetwo right-hand valves in Fig. 1, wascommonly used in those days as afuse in the h.t. circuit. There aremetal cans below the first and thirdtriodes, which look to me likeintervalve transformers. If so, theywould have primary and secondarywindings connected to fourterminals and possibly marked 'IP'and 'OP' (input and output primary)on one side and 'IS' and 'OS' (inputand output secondary) on the other.
The transformer windingsshould also be checked forcontinuity, because if any one wasopen -circuit on either transformer.the set would fail to function. It'sworth remembering that transformer
64 Practical Wireless, March 1993
windings are vulnerable to goingopen -circuit when a set is out ofaction or stored in dampsurroundings for long periods.
Valve Faults
It is important to stress at thispoint that a battery valve runs cool.but BEWARE of a mains valve. Thisis because its glass envelope getsvery hot and will burn your hand ifyou try to remove it without caution.
On one occasion, I found twovalves in a television receiver withtheir glass envelopes cracked.However, after a few enquiries Ilearnt that the customer had wateredthe plants on a shelf above the setand some of this cold liquid hadleaked through the back panel on tothe hot valves!
In general, a directly heated(battery) valve requires 1.5 or 2V tolight its filament. There was around100V on its plate, whereas theheating element within an indirectlyheated (mains) valve requires 6.3 orI2V to raise its cathode to thenormal working temperature. Thisshould explain why a battery setcomes to life almost immediately,and a mains set takes a time to`warm-up' after switch -on before itcan be used.
CommunicationsReceiver
When operating a valvedcommunications receiver, it's best toswitch it on at least 30 minutesbefore use. This is so that the valves,especially the local oscillator, cansettle down.
This action will help to preventfrequency drifting on the short wavebands at the start of operations.
Sometimes, following thereplacement of a faulty localoscillator valve in such a receiver,the dial calibration 'wanders' or is abit out. This usually corrects itselfafter the new valve has (aged) beenworking for several hours.
Octal Valves
Some of you may have noticedthat the octal valves used in thecrystal calibration oscillator fitted tothe Canadian Army WS -52, have thebase of their locating spigot paintedblue. This indicates that theseparticular valves have beendeliberately 'aged' by the makers
and are suitable for immediate use inan oscillator. Ageing simply meansthat, although brand new, the valvehas been run for an agreed period,by the makers, before packing.
I think that the most commonvalve fault is an open circuitfilament or heater. This is proved byremoving the suspect valve from itsholder and connecting an ohm meteracross the pins marked 'F' in Fig. 3or 'H' in Fig. 4 to check forcontinuity. (These are NOT thecorrect pin numbers). NEVERswitch a set on and off rapidly, assurge currents associated with thisaction, can easily damage this partof a valve.
Other reasons for replacing avalve are low emission, intermittentoperation and microphony. Poorreceiver performance, due to lowemission, means that the filament orcathode in the offending valve is notproducing enough electrons. A set
will stop and start if the connectionto an electrode inside a valve hascome loose. This is more likely tooccur in mains valves because oftheir high working temperatures,than in battery valves.
A strange musical 'booming',more like a 'boi-oi-oing', comingfrom the loudspeaker, when thecabinet is touched or when a pieceof music produces a hefty bass note,is probably caused by a valve thathas decided to work more like amicrophone. In the early battery setsyou often find a 'wobbly' valveholder which prevented this noisebeing a nuisance
Valve Data Lists
I suggest that all collectors ofvintage sets should keep an eye openin the second-hand book shops forvalve data and equivalents lists.These were published by such
Fig. 2: A typical'wet' 2Vaccumulator.
Fig. 3: The basiclay -out(simplified) of adirectly -heatedtriode.
Fig. 4:Simplified lay-out of anindirectly -heated filamentvalve for a.c.use.
manufacturers as Brimar, Cossor,Dario, Ediswan, Ever Ready,Ferranti, Marconi, Mazda, Mullard,Osram, Philips and Tungsram, or bytechnical book publishers likeBemards or Wireless World.
For instance, I looked for apossible screen -grid valve for theSelecta, Fig. 1, in my third edition(1958) copy of the InternationalRadio Tube Encyclopaedia byBernard B. Babani. One possiblevalve I found was a 2V tetrode(SG220) which has an extra gridbetween the control -grid and theanode.
The valve manual told me that,unlike the triode, the anodeconnection for this particular valveis its top -cap. Briefly, theintroduction of this extra grid helpedto break the inter -electrode capacitybetween the control -grid and theanode. By operating this second gridat a lower voltage than the anode, itgave the set designer more controlover this type of valve in front-endcircuits.
A comprehensive valve manualis a valuable asset. This is becausefor about 60 years, a multitude ofvalves were made covering a widevariety of types with differing baseconnections, pin configurations andworking voltages.
In addition, the valve world hasdirect equivalents and similar typesfor special purposes. For example,the Marconi KTW63 is equivalent toan American 6K7, and a MullardEF39 is equivalent to a Cossor 0M6and a Marconi W147.
NEVER replace a valve byguess work. Always check yourvalve data book before making thechange, because there may be aslight difference which will effectyour particular circuit.
The popular 6K7 has a top -capcontrol -grid which is ideal for shortscreened -leads to i.f. transformers ortuning capacitors. However, in anumber of sets it was moreconvenient for this grid to come outto a pin in the base. That need wasmet by the valve makers with a6SK7, which put the control -griddown below but also changed someof the other electrode/pinconnections.
Don't forget to write to me at'Faraday', Greyfriars,Storrington, West Sussex RH2O4HE. See you next month.
Practical Wireless, March 1993 65
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MARCONI TH293A AUDIO WATTMETER I rrW to 10 Watt 4E22 IP&P1E5DUAL GATE MOS PETS 0F980 140 35p. 4 for El 20TOKO IF TRANSFORMERS 10 7MHz Type KACS6184 4 35p, 4 for (I 20AIRCRAFT ARTIFICIAL HORIZON MI(30 Collectors Item 4(18 00 WISP E4 001SCREW TERMINAL ELECTROLYTICS 15.000ot 40v w 4 75p. 10.000uf 25v w 4 50pBRIDGE RECTIFIERS 00 Ply 25 amp 4 El 30 400 PIV 8 amps TRIACS 4 4 foi C2S C ITS THYRISTORS 600 PIV 25 amp a (I 00. 600 POI 2 amp 4 SOO30rom x 75mre OCTAL PLUG/IN COIL FORMERS 4 Et 50. 5mm COIL FORMERS 4 10pASSORTED YARliCAP DIODES 50 V 75p. 10Opt 4 10 for 60p. 30301 10 10 for 75pCOMPRESSION TRIMMERS 25p1 4 20p. 30pf 4 20p, 50pf ?Op. 85p1 4 35p
AIR SPACED VARIABLE CAPACITOR 350.3500f with VHF Panel attached 4 E395DRY FIT TYPE RECHARGABLE BATTERIES 208-305 8 Volt 3410 4 C2 95 IMP 13 301.2 for 0 00 IPA& 04 001AIR SPACED VARIABLE CAPACITORS 350.4003030pf with Geared S M Drive 4 E2 95, 400350.303030p1 withSM Unvc i7 07 95. 250.250-20.20.2001 with S M Drive 4 E395R.F. TRANSISTORS 2N6166, 1 75MH2 100 Wan with data 4 E12 50, MRE392 30 to 500MHz 125 Watt with date 4 (26.95,THAIS IMRF 4291 150 Wan Linear 2 to 30 Wan 4E1595. MRE136 R F FET 210 400 MHz 15 Wan with data 4E9.95
ACCESS and BARCLAY CARDS accepted. P&P 60p under C5 Over Free. Unless otherwise stated
C.M. HOWES KITS. Available by post and for callers.
RST MAIL ORDER CO.LANGREX SUPPLIES LTD.
1 MAYO ROAD.CROYDON.
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SPECIAL EXPRESSRS MAIL ORDER SERVICEfp i, 35. 1 14 vo52 150 200 6517 354
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EC91 650 00 819 540 12866 2.50ECC33 750 1132 50 5(241 600 56563 454 12016 2.50ECC35 750 13733 SO 5P61 4w 600 ':531;65 650lam 225 6130 GE 50 U19 10 013 050 713276 GE 754FCC82 225 6Z31 50 U25 250 150 12E1 7000ECC83 Siemens 3 00 6r61 50 U76 250 750 1206711017 6 50
ECC85 350 K1E4 12 513 1131 750 1 95 30E1122 1 SO
ECC88 4 IS 6766 GEC P 0 A UA8080 150 350 30P4 250E0091 200 Kr% 15 00 18F89 150 354 501319 2.501080 150 678 900 00/142 400 500 66113 150EC1135 350 .'542 2 70 11C11131 250 375 3133114 1.80
ECM? 350 270 UCL87 200 525 300B(PR) 154.54ECH8I 3 CO 150 UCL87 300 654 Mee 11.08(CI 80 150 250 UF89 200 500 D35 54.54ECL82 1 50 2207 100 0L41 10 00 350 547 5.54
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FUN ma 250 PC190 100 Oval 400 950 8124 52 50
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F7370 50 11086 250 VR105, 250 50312 1 % 73333 65001039 25 1'0331 250 0,11503: 150 626 350 75 NEF40
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EE54 50 K1E12 154 4CX2S013 OW 2500 616 354 55149 1541155 50 P6183 3 DO 40(2508 SIC 85 00 617 154 5042 11 00
EF80 SO PC184 2 00 50463 600 60365 GI 15 00 6080 I SO
EF85 50 '01 85 150 51246 5 25 60E6C 12 50 61468 GE 15 00
EF86 00 PC186 250 9V46 4 03 60560 GI II 25 65500 GE M NEF91 95 P61805 250 3036r 250 60661 3 GO 61538 GE 16 00
E192 15 60600 600 527 454 667 154 E473 1154EF183 54 7S t 203 150 51463 150 6613 4 00 ',125 GE 7 00
mew 54 P136 250 63012 175 6606 GE II% '177461 12 50
OHIO 75 itt81 r75 6487 354 6166 3350 3139 1000EL32 50 0E17 1 SO 66146 4 03 5L6GC531 950 3360 76 %ELMF4.34 Swum
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E104 275 73519 600 6805 375 61511118:6668 12 00 4060 16o)ELM 2 If 15802 6 03 5A69 15 00 13307 3 00 114176E PeeEL91 154 2033 750 66S6 654 6SC7 354 RIMS caned %ion pangEL95 200 0261 150 616/6 950 66GM 250 %Dow
Tel: 081-684 1166 Open daily to callers Mon -Fri 9am-4pm - closed Saturday Fax: 081 684 3056Tubes and Transistors= dock.
Terms0 types available 1rfromes.Over 60
Terms C W 0 and Visa and Access cards accepted AtikOrders despatched by return
Prices excluding Quotations for any types not listed S A E TelexVAT add 17.5% P&P 1-3 Valves E1.00 VAT, 4.6 Valves E2.00 VAT 946708
VARIACS general purpose 240v/270v 2 amp units for int mounting 0/Pvar 0 to 240 270v (no knob or dial) new boxed. £26.50 or 2 for £48AERIAL COUPLER Aerial tuner for use with R234 Rx 2/27 Megs in 4bands to match Whip or Long Wire to 75 ohm size 9 x 7 x 8" (can alsobe used with R210) £35 also available matching Acceptor unit see list.ARMY VHF Rx R216 20/155 Megs AM/FM see list for spec £125POWER MODULES stab HT 200/300v 100 Ma & three x 6.3 at 1/2/4amps size 9 x 6 x 6" £27.50 R.F. HEAD UNITS part of Army GS.20Radar now freq 8.5 Gz with tunable Gunn Diode Doplar type unit with intAe ass £24.50 also available 360' LCD display units £16.50 P.A. TYPEAMPS 240v I/P rated 200 watt (Dip 100 volt line (0/P Trans tapped sec)in 19" table case transist type (Amp only no pre amp) £85 DEVIATIONMETERS TF791 D 21 000 Megs 0 to 125 Kc deviation in 4 ranges tested£85 TRANS HT 200/250v Sec 220v at 500 Ma & 1125-0-1125v at 400Ma (1125v DC 400Ma) C core new cont rating £34 R.F. AMP part ofD.11 Tx on 19" panel 2/22 Megs about 400 watts with var ind. cap etcless valves with circ. £55 OPTICAL ACCS mixed selection of items inceyepiece lens cell. lenses. prisms etc mostly new approx 12 items. £23AERIAL DIPOLE for AC mounting approx 420/450 Megs with UHFconn & mt brk new 2 for £9 also Military type UHF 225/400 MegsDiscone aerials size approx 30" long 14" dia as these have been outsidefor some time, some refurbishment required. £32 MORSE KEYS Armygeneral purpose adjustable. £8.50 GRL BRIDGE CT492 Auto Balancebridge with decade meter indication for use on 9v int battery tested. £65STANDARD CELLS Muirhead 1.0192 volts size Th x 1)/ x Y." £9.50 SIGGENS Marconi TF995A2 General purpose AM/FM 1.5 to 220 Megs varMod & Deviation for 240v tested with book few only. £95 AMPLIVOXASTROLITE HEADSET comprises headset with boom mike modernlight grey phone nom 100 ohm mike 600 ohms fitted GPO pattern 4 ringjack plug new £25 AERIALS base station RT type as ground plane66/78 megs 50 ohm approx overhaul height 6'6" new made by HMPDenmark for 50 ohm system quality unit new. £28 MOTOROLAMX300R handy talkies 136/150 Megs FM 2.5 watt 7.2v batt note thesehave faulty freq synth modules with arcs etc no accs. £24.50 (willconvert to 2mt Rx) PRESSURE GAUGES range 34/1350 mbs mainsoperated see list. £65 CONTROL UNIT remote for aircraft cameracontains 24v DC motor, gears. etc sets number & time intervalcontained in neat wood case. £14.50Above prices are inclusive. Goods Ex equipment unless stated new.
2 x 24p stamps for list 50-1.
A. H. SUPPLIESUnit 12 Bankside works.Darnall Road, Sheffield S9 5HAPhone: (0742) 444278
66 Practical Wireless, March 1993
OUT NOW!
The Brand New Cirkit ElectronicConstructors Catalogue
Winter 92/93 192 pages £££'s worth discount vouchers 100s new products
Books - the latest titles.Capacitors - new range ceramic discs, extended rangeselectrolytic and polyester types.Computers - new CAD PCB layout software.Connectors - extended ranges of BNC, Jacks, XLR andPCB types.
Filters - new narrow band ceramic and low pass TV filters.Hardware - additions include new range control knobs,cabinet hardware and heatsinks.Inductors - more additions to our already extensiverange.
Kits - new additions to the Velleman range.Rigs - handheld 'CB' transceiver, wavemeters andscanning receiver accessories.Semis - new linear ICs, transistors and a complete newrange of LEDs including blue types.Speakers - new radio mic systems.Test Equipment - new hand-held frequency meter andsatellite TV dish alignment system.And much more besides
Send for yourcopy today!
(-1CIRKIT DISTRIBUTION LTD
Access
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Telephone (0992) 444111 Fax (0992) 464457
Practical Wireless, March 1993
Amateur RadioCommunications Ltd
OUR CUSTOMERS TELLUS WE GIVE A
SERVICE THAT IS 1000/0SATISFACTORY
We stock most items advertised in this magazine. So, forcompetitive prices and a service guaranteed, find out for
yourself and phone today.
FACTBecause of the
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prices zaiic_ealrat the rate of 10-15%
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So don't delay yournext purchase.
ICOM IC -3230H
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* High Sensitivity
NEW FROM YAESU KENWOOD ALINCOFT530 TH-78 DJ -580
Latest edition to the Compact dualband This dualbanddualband handheld range. handheld. Easy to use handheld is as popular5w, 2m and 70cms, dual rx plus a multitude of as ever. Great value
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STOP PRESSCOMMISSION ITEMS NOW ON SALEIC -735 £750 * IC -720 + PSU £550 * TS -440 + PSU &SPKR £950 * TS -120V £325 * SPC-300ATU £175 *FT -78 + DISPLAY £325 * FT -726 2m/6m £600 *FRG -7700 £250 * TS -440 £850 * DRAKE R8E £599* FT-902DE + ATU & SPKR £845 * FT -290 £225 *IC -735 + PSU £899 * FT -480 £275 * FT -780 £295
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67
EMC PROBLEMS?DON'T PANIC!
Achieving electromagnetic compatibility(EMC) with the increasing number ofelectronic devices in surrounding homescan be a major problem for today's radioamateur.
This timely guide will help you toavoid EMC problems by practising goodradio housekeeping, and assist you withthe diagnosis and cure of any ones whichdo occur. The underlying causes, as wellas the remedies, are given so that youshould be well prepared to tackle anyproblems which turn up now or in thefuture. The social dimension is notforgotten, and a whole chapter is devotedto dealing with neighbours.
The book's positive, light-heartedapproach to problem -solving should bereassuring if you are faced with asudden crisis - where appropriate,summaries are included at the end ofchapters to give 'immediate action'information.
If trouble ever comes to your door,reach confidently for this book
. and don't panic! £8.50244 by 183mm; 117 pages; £6.50 incl p&p
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0707 49855 or send cheque/PO with order.(Please allow up to 28 days for delivery)
RADIO SOCIETYOF GREAT BRITAIN
Dept PW, Lambda House, Cranborne Road,Potters Bar, Herts, EN6 3JE. Tel: 0707 59015
TX -3 RTTY CW ASCII TRANSCEIVEHigh performance, low cost. Unbeatable features.tape £25, disc £27. SPECTRUM tape £40,adaptor board. VIC20 RTTY CW program tapeTIF1 interface or a terminal unit.
GX-2 FAX SSTV TRANSCEIVEAll modes of FAX and colour/mono SSTV. ReviewCom. BBC only. Complete system only £99direct printing option.
RX-8 MULTIMODE RECEIVEFax to screen and printer, colour SSTV, HFRTTY, AMTOR, CW, ASCII, UoSAT. Everyprinter support. Review in July 91 Rad Com.system only £259. DISCOUNT for RX-4 users.
RX-4 RTTY CW SSTV AMTORStill a best-seller. BBC, CBM64 tape £25, disc£25. SPECTRUM tape £40, +3 disc £42 incneed our TIF1 interface. SPECTRUM softwareTIF1 INTERFACE for best HF & VHF performancesoftware. Kit £30, ready-made and boxed £40.RX-4 software.
APT -I WEATHER SATELLITEConverts satellite signal for display on any FAXuse with RX-8, all connections included andordered at same time as RX-8.
FAX AND WEATHER SATELLITESFull resolution charts and greyscale pictures forcomputer to a dot matrix printer. FAX £80 or£139.
Also MORSE TUTOR £8, LOGBOOK £8, RAE MATHS £8VIC20, SPECTRUM. BBC LOCATOR with UK, Europe,
All available on disc £2 extra. Full info available on everything.PRICES INCLUDE VAT AND P&P BY RETURN
A W .A' technical software
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SYSTEMand VHFfeature.
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FOR SALE: 4CX250B and 4CX350A EIMAC and src refurbished and fully tested at highpower (ex -equipment) £25 plus VAT, post paid. Discount for 10 or more!FOR SALE: Sockets for 4CX2508 by AEI UK. ex -equipment but working and clean at £17 each,discounts for larger quantities. Ceramic circular chimney for same at £8 each.WANTED VALVES: KT66, KT77, KT88, PX4, PX25 valve collections. klystrons. magnetrons.transistors. Please post us list of what you have. Quick replies, cash waiting.
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PICKETTS LOCKWe will again be at this popular rally and look forward to meeting many of those Amateurs and SWLs who
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To gel the best resale value, I can sell your computer for you at an agreed price. I will give a 3 monthwarranty to the purchaser, so everybody gets a bargain. So if you are buying or selling call me fora quote.
REPAIRS Phone for a diagnosis and estimate. 73s John G3TLU
UNIT 5, STANLEY HOUSE, STANLEY AVENUE, WEMBLEY, MIDDX HAO 4JB
c nr,-., n -) U EI © c-,..,./, i__ _P} AMATEUR ELECTRONICSG3LLL for ICOM & YAESU and AOR SCANNERS
New & S.H. Receivers, Transceivers & Specialist service for older rigs,valves and cw filters for FT101 etc. Closed all day Thursday.
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68 Practical Wireless, March 1993
RC ADEThe PW Shopping ArcadeWelcome to the Practical Wireless 'Arcade'. In this section of the magazine, you'll be able to find all thoseimportant services 'under one roof' - just like the shopping arcades you see in the High Street.
Let you eyes 'stroll through' the Arcade every month and you'll find all departments open for businessincluding: The Book Service, PCB Service, Binders and details of other PWServices. Make a regular habit of'visiting' the Arcade, because in future, you'll have the chance of seeing special book offers and otherbargains. And don't forget, this Arcade is open wherever you're reading PW!
Services
Queries:Practical Wireless,PW Publishing Ltd., Arrowsmith Court,Station Approach,Broadstone, Dorset BH18 8PW.
We will always try to help readers having difficulties with PracticalWireless projects, but please note the following simple rules:1: We cannot deal with technical queries over the telephone.2: We cannot give advice on modifications either to our designs,to commercial radio , TV or electronic equipment.3: All letters asking for advice must be accompanied by astamped self-addressed envelope (or envelope plus IRCs foroverseas readers).4: Make sure you describe the problem adequately, with as muchdetail as you can possibly supply.5: Only one problem per letter please.
Back Numbers
Limited stocks of many issued of PW for past years are availableat £1.80 each including post and packing. If the issue you want isnot available, we can photocopy a specific article at a cost of 85pper article or part of article.Over the years, PW has reviewed many items of radio relatedequipment. A list of all the available reviews and their cost can beobtained from the Editorial Offices ar Arrowsmith Court, StationApproach, Broadstone, Dorset BH18 8PW for a stamped self-addressed envelope.
Binders
PWcan provide a choice of binders for readers' use. Plain bluebinders are available, each holding 12 issues of any A4 formatmagazine. Alternatively, blue binders embossed with the PW logoin silver can be supplied. The price for either type of binder is£5.50 each (£1 P&P for one, £2 for two or more.Send all orders to PW Publishing Ltd., FREEPOST, ArrowsmithCourt, Station Approach, Broadstone, Dorset BH18 8PW.
Constructional Projects
Components for PW projects are usually readily available fromcomponent suppliers. For unusual or specialised components, asource or sources will be quoted.Each constructional project is given a rating to guide readers as tothe complexity.Beginner:A project that can be tackled by a beginner who is ableto identify components and handle a soldering iron.Intermediate: A fair degree of experience of building radio orelectronic projects is assumed, but only basic test equipment willbe needed to complete any tests and adjustments.Advanced: A project likely to appeal to the experiencedconstructor. Access to workshop facilities and test equipment willoften be required. Definitely not for the beginner to attemptwithout assistance.
Mail Order
All items from PW are available Mail Order, either by post orusing the 24hr Mail Order Hotline (0202) 659930. Payment shouldbe by cheque, postal order, money order or credit card(Mastercard and Visa only). All payments must be in sterling andoverseas orders must be drawn on a London Clearing Bank.Practical Wireless, March 1993
PW PCB Service
The p.c.b.s. for all the latest projects are now available. We have astock of boards for many other projects produced in the past, butthese stocks are subject to variation. Please add £1 p&p to ordersfor one board (or one set of boards) and £2 p&p to orders for twoor more p.c.b.s.
You can telephone your order in by calling (0202)659930 at any time. Please allow 28 days for delivery.
Club Discount. An additional saving.Radio and electronics club members, save money on p.c.b.s whenyou order through your club. Tell your club secretary to send fordetails, marking the envelope 'PCB discount information' to oureditorial offices.
Board Article (Project) Title Issue Price
WR314 UHF Pre -Amplifier Dec 92 £3.45WR313 10MHz Transmitter Nov 92 £4.65WR312 Receive/Mixer (Getting Started) Nov 92 £4.15WR311 Oscillator BFO (Getting Started) Sept 92 £2.60WR310 1.2GHz Pre -scaler Aug 92 £3.75WR309 Volt Reg/Divide by 100 Aug 92 £3.15WR308 TTL 1MHz Oscillator (Getting Started) July 92 £2.20WR307 Crystal Checker (Getting Started) June 92 £4.25SET WR303/304/305/306 Apr 92 £19.30
Inductance BridgeWR302 GDO (Getting Started) Apr 92 £4.75
WR301 Challenger Receiver Feb 92 £4.75WR300a OSCAMP Oscillator Mar 92 £4.75WR300 OSCAMP Amplifier Feb 92 £5.20WR299 Multivibrator (Getting Started) Jan 92 0/SWR297/298 Additional Beaver boards 0/SSET WR295/296 PW Beaver Oct 91 £12.00SET WR292/293/294 Chatterbox Aug 91 £14.00SET WR290/291 Robin Freq. Counter Aug 91 0/SSET WR292/293/294 Chatterbox Aug 91 £14.00
WR289 Mean -4 (Control) Jul 91 £4.67WR288 Morse Master Jun 91 £4.89WR286 Meon-4 (RF PA) Jun 91 £5.54WR287 Morse (Speedbrush) May91 £4.85WR255 Meon-4 May91 £6.76WR285 Scope Probe PSU Apr 91 £4.87WR284 Scope Probe Apr 91 £5.75WR283 Sudden Receiver Mar 91 £4.54WR282 Repeater Toneburst Feb 91 £5.10WR281 High Voltage PSU Jan 91 £4.70SET WR263/264 +VVR276-80 Jul 90 £21.96
Marland Transmitter Sep 90WR272 NiCad Recycler Jun 90 £7.06WR275 Low Voltage Alarm Jun 90 £6.49WR273 Valve PSU May 90 £7.00WR274 RX Attenuator May 90 £5.84WR271 Product Detector Apr90 £5.05
WR270 Badger Cub Apr90 £5104WR269 Glynme Feb 90 £6.83WR268 lrwell (RF PA) Feb 90 £6.12WR264 lrwell (Relay) Feb 90 £5.10WR263 lrwell (VFO) Jan 90 £6.12
WR267 PW 49'er Jan 90 £6.12WR266 Tuned Active Antenna Jan 90 £5.71
WR265 Tuned Active Antenna (PSU) Jan 90 £5.71
WR199 Meon 50MHz Transverter Oct 85 £6.83WR161 Marchwood 12V 30A PSU Jul 83 £4.28
Please use the order form on page 73for all items in the PW arcade.
69
The books listed have been selected as being of special interest to our readers. They are supplied directto your door. Some titles are overseas in origin.
HOW TO ORDER. PLEASE USE THE ORDER FORM ON PAGE 73.POST AND PACKING; add £1.00 for one book, £2.00 for two or more books, orders over £40 post and packing free, (overseas
readers add £1.75 for one book, £3.50 for two or more for surface mail postage) and send a postal order, cheque or internationalmoney with your order (quoting book order code, e.g. ABRN, and quantities) to PW Publishing Ltd, FREEPOST, Arrowsmith Court,
Broadstone, Dorset BH18 8PW. Please make your cheques payable to PW Publishing Ltd. Payment by Access, Mastercard,Eurocard or Visa also accepted on telephone orders to Poole (0202) 659930. Books are normally despatched by return of post but
please allow 28 days for delivery. Prices correct at time of going to press. Please note: all payments must be made in Sterling.
LISTENING GUIDES
AIR BAND RADIO HANDBOOK (4thEdition) ABRHDavid J. SmithExtensively revised & updated(October 1992). Air band radiolistening enables you to listen -in onthe conversations between aircraftand those on the ground who controlthem, and is an increasingly popularand fascinating hobby. A new chapteron military air band has been added.The author, an air traffic controller,explains more about this listeninghobby. 190 pages. E7.99
AIR TRAFFIC RADIO 8th Edition ATRCompiled by Ken DaviesCompletely revised (early 1992) tomake this a comprehensive guide toUK airband communications.Frequencies and abbreviations usedin UK air traffic control. Where tolisten for tower, ground and radarcontrol in civilian and other airports.Includes a section on off -shore oilrelated use. 72 pages. E4.50
COMPLETE VHFAJHF FREQUENCYGUIDE (THE) CVUFThis book gives details of frequenciesfrom 26-2250MHz with no gaps andwho uses what. Recently updated(August 1992), there are chapters onequipment requirements as well asantennas & the military aeronauticalband between 225 & 399MHz.88 pages. 0/P
DIAL SEARCH 1992/94 DSGeorge WilcoxThe listener's check list and guide toEuropean radio broadcasting. Coversmm.,I.w., v.h.f. & s.w., including twospecial fold -out maps. Also includes afull list of British stations, a select listof European station, broadcasts inEnglish and Making to 'Most of YourPortable'. 46 pages. £425
FERRELL'S CONFIDENTIALFREQUENCY LIST 8th edition FCFLCompiled by Geoff HalligeyCompletely revised, much larger &spirally bound for easy use. Nowcovers 1.6-28MHz in great depth, allmodes and all 'utility' services, withnew reverse frequency listingshowing every known frequencyagainst each callsign. Who's usingwhat frequency and mode, what's thatcallsign? These are some of theanswers this book will help you find.544 pages. E17.95
FLIGHT ROUTINGS 1992 FR92Compiled by T.T. & S.J. WilliamsThis guide was produced with thesole aim of assisting airband listenersto quickly find details of a flight, oncethey have identified an aircraft'scallsign. Identifies the flights ofairlines, schedule, charter, cargo andmail, to and from the UK and Eire andoverflights between Europe andAmerica. 122 pages. 0/P
GUIDE TO FACSIMILE STATIONS 12thEdition GTFS12Joerg KlingenfussThis manual is the basic referencebook for everyone interested in FAX.Frequency, callsign, station name, ITUcountry/geographical symbol.technical parameters of the emissionare all listed. All frequencies havebeen measured to the nearest 100Hz.Included are 300 sample charts andtheir interpretation.416 pages E18.00
GUIDE TO FORMER UTILITYTRANSMISSIONS 3rd Edition GTFU3Joerg KlingenfussBuilt on continuous monitoring of theradio spectrum from the sixties untilthe recent past. A useful summary ofthe former activities of utility stationsproviding information for theclassification and identification of'new' & 'unknown' radio signals.227 pages. £8.00
GUIDE TO UTILITY STATIONS 11thEdition GTUS11Joerg KlingenfussThis book covers the complete shortwave range from 3 to 30MHz togetherwith the adjacent frequency bandsfrom 0 to 150kHz and from 1.6 to3MHz. It includes details on all typesof utility stations including FAX andRTTY. There are 19549 entries in thefrequency list and 3590 in thealphabetical callsign list plus pressservices and meteorological stations.Included are RTTY & FAX press andmeteo schedules. There are 11800changes since the 10th edition.534 pages. £24.00
HF OCEANIC AIRBANDCOMMUNICATIONS 4th Edition HOACBill LaverHF aircraft channels by frequency andband, main ground radio stations,European R/T networks and NorthAtlantic control frequencies.31 pages. E3.95
INTERNATIONAL RADIO STATIONSGUIDE BP255Peter ShoreAs in 'Broadcast Roundup', hiscolumn in PW, Peter Shore has laidthis book out in world areas, providingthe listener with a reference workdesigned to guide around the ever-more complex radio bands. There aresections covering English languagetransmissions, programmes for DXersand s.w.l.s. Along with sections onEuropean medium wave and UK f.m.stations. 266 pages. E5.95
INTERNATIONAL VHF FM GUIDE(THE) IVFG7th Edition.Julian Baldwin G3UHK & KrisPartridge G8AUUThis book gives concise details ofrepeaters & beacons world-wide pluscoverage maps & further informationon UK repeaters. 70 pages. E2.85
MARINE UK RADIO FREQUENCYGUIDE MURFBill LaverA complete guide (reprinted August1992) to the UK s.w. and v.h.f. marineradio networks. Useful information,frequency listings and the WorldMarine Coastal Phone Stations.62 pages. £4.95
NEWNES SHORT WAVE LISTENINGHAND BOOK NSWLJoe Pritchard G1UQWA technical guide for all short wavelisteners. Covers construction anduse of sets for the s.w.l. who wants toexplore the bands up to 30MHz. Alsocovers the technical side of the hobbyfrom simple electrical principles allthe way to simple receivers 276pages. £15.95
POCKET GUIDE TO RTTY AND FAXSTATIONS (THE) PGTRBill LaverA handy reference book listing RTTYand FAX stations, together withmodes and other essentialinformation. The listing is in
ascending frequency order, from 1.6to 26.8MHz. 57 pages. E3.95
RADIO LISTENERS GUIDE 1992 RLG92Clive WoodyearThis is the third edition of this radiolistener's guide. Simple -to -use mapsand charts show the frequencies forradio stations in the UK. Organised sothat the various station types arelisted separately, the maps are usefulfor the travelling listener. Articlesincluded in the guide discuss v.h.faerials, RDS, the Radio Authority anddevelopments from Blaupunkt.56 pages. E2.95
SHORT WAVE LISTENER'SCONFIDENTIAL FREQUENCY LIST 8thEdition SWLCBill LaverCovering the services andtransmission modes that can be heardon the bands between 1.635 and29.7MHz. The guides main objective isto quickly direct the listener to thefrequency, or band of frequenciesmost likely to provide the type ofstations that are being sought.187 pages. E8.95
SOUNDS EASY The complete guide toBritain's radio stations SECompiled by Ken DaviesA guide to the numerous local radiostations throughout the UK. If you do alot of travelling this book is invaluable.Itemised by areas, it makes findingyour kind of sounds easy.52 pages. £2.95
VHF/UHF AIRBAND FREQUENCYGUIDE 4th Edition VUAFA complete guide to civil & militaryairband frequencies including how toreceive the signals, the frequenciesand services. VOLMET, receiverrequirements, aerials and much moreabout the interesting subject ofairband radio are included.123 pages. E6.95
ANTENNAS (AERIALS)AERIAL PROJECTS BP105Practical designs including active,loop and ferrite antennas plusaccessory units. 96 pages. £2.50
ALL ABOUT CUBICAL QUADANTENNAS AACOWilliam I. Orr W6SAI and Stuart D.Cowan W2LXThe quad antenna came into being,and popularity, over 50 years ago. Thisbook shows you how to design buildand 'feed' this versatile antenna. Ifyou just want to build one, there areready -to -go designs for bandsbetween 7 & 50MHz.709 pages. E6.75
ANTENNA EXPERIMENTER'S GUIDE(THE) AEGPeter Dodd G3LDOAlthough written for radio amateurs,this book will be of interest to anyonewho enjoys experimenting withantennas. You only need a very basicknowledge of radio & electronics toget the most from this book. Chaptersinclude details on measuringresonance, impedance, field strengthand performance, mats andmaterials and experimental antennas.200 pages. f8.90
ANTENNA IMPEDANCE MATCHINGAIMWilfred N. CaronProper impedance matching of anantenna to a transmission line is ofconcern to antenna engineers and to
every radio amateur. A properlymatched antenna as the terminationfor a line minimises feed -line losses.Power can be fed to such a linewithout the need for a matchingnetwork at the line input. There is nomystique involved in designing eventhe most complex multi -elementnetworks for broadband coverage.195 pages £11.95
ARRL ANTENNA BOOK (THE) 16thEdition MBA station is only as effective as itsantenna system. This book coverspropagation, practical constructionaldetails of almost every type ofantenna, test equipment and formulasand programs for beam headingcalculations. 789 pages. £14.50
ARRL ANTENNA COMPENDIUM (THE)Volume OneAAC1Fascinating and hitherto unpublishedmaterial. Among the topics discussedare quads and loops, log periodicarrays, beam and multi -bandantennas, verticals and reduced sizeantennas. 175 pages. E9.50
ARRL ANTENNA COMPENDIUM (THE)Volume Two AAC2Because antennas are a topic ofgreat interest among radio amateurs,ARRL HQ continues to receive manymore papers on the subject than canpossibly be published in OST. Thosepapers are collected in this volume.208 pages. E9.50
BEAM ANTENNA HANDBOOK BAHW. I . Orr W6SAI & S. D. Cowan W2LXDesign, construction, adjustment andinstallation of h.f. beam antennas. Theinformation this book contains hasbeen complied from the data obtainedin experiments conducted by theauthors, and from informationprovided by scientists and engineersworking on commercial and militaryantenna ranges. 268 pages. E7.50
G-ORP CLUB ANTENNA HANDBOOK(THE) GCAHCompiled and edited by P. LinsleyG3PDL & T. NicholsonKA9WRI/GWOLNQ.This book is a collection of antennaand related circuits taken from Sprat,the G-QRP Club's journal. Althoughmost of the circuits are aimed at thelow -power fraternity, many of theinteresting projects are also useful forgeneral use. Not intended as a textbook, but offers practical and provencircuits. 755 pages. £5.00
HF ANTENNA COLLECTION (RSGB)HFACEdited by Erwin David G4LQIThis book contains a collection ofuseful, and interesting h.f. antennaarticles, first published in the RSGB'sRadio Communication magazine,between 1968 and 1989, along withother useful information on ancillarytopics such as feeders, tuners,baluns, testing and mechanics for theantenna builder. 233 pages. £9.50.
INTRODUCTION TO ANTENNATHEORY (AN) 8P198H. C. WrightThis book deals with the basicconcepts relevant to receiving andtransmitting antennas, with emphasison the mechanics and minimal use ofmathematics. Lots of diagrams helpwith the understanding of thesubjects dealt with. Chapters includeinformation on efficiency, impedance,parasitic elements and a variety ofdifferent antennas. 86 pages. £2.95
NOVICE ANTENNA NOTEBOOKDoug DeMaw W1FB NANAnother book from the pen of W1FB,this time offering "new ideas forbeginning hams". All the drawings arelarge and clear and each chapterends with a glossary of terms. It iswritten in plain language and youdon't need to be a mathematician tobuild and erect the support structuresthat are presented in this book.124 pages. £6.95
SIMPLE, LOW-COST WIREANTENNAS FOR RADIO AMATEURSSLCWW.I. Orr W6SAI & S. D. Cowan W2LXEfficient antennas for Top Band to 2m,including 'invisible' antennas fordifficult station locations. Clearexplanations of resonance, radiationresistance, impedance, s.w.r.,balanced and unbalanced antennasare also included. 188 pages. E7.50
W1FB'S ANTENNA NOTEBOOK WANDoug DeMaw W1FBThis book provides lots of designs, insimple and easy to read terms, forsimple wire and tubing antennas. Alldrawings are large and clear makingconstruction much easier. There is nohigh-level mathematics in this book,just simple equations only whennecessary to calculate the length ofan antenna element or its matchingsection. 123 pages. £6.95
WIRES & WAVES WAWCollected Antenna Articles from PW1980-1984Antenna and propagation theory,including NBS Yagi design data.Practical designs for antennas frommedium waves to microwaves, plusaccessories such as a.t.u.s, s.w.r. andpower meters and a noise bridge.Dealing with TVI is also covered.160 pages. E3.00
YAGI ANTENNA DESIGN YADDr James. L Lawson W2PVThis book is a polished and expandedversion of a series of articles firstpublished in Ham Radio following onfrom a series of lectures by theauthor, who was well-known as theexpert on Yagi design. Chaptersinclude simple Yagi antennas, loopantennas, effect of ground, stackingand practical antenna design.210 pages. E10.95
25 SIMPLE AMATEUR BAND AERIALSBP125E. M. NollHow to build 25 simple andinexpensive amateur band aerials,from a simple dipole through beamand triangle designs to a mini -rhombic. Dimensions for specific spotfrequencies including the WARCbands are also given. 63 pages. E1.95
25 SIMPLE INDOOR AND WINDOWAERIALS BP136E. M. NollDesigns for people who live in flats orhave no gardens, etc., givingsurprisingly good results consideringtheir limited dimensions. Informationis also given on short wave bands,aerial directivity, time zones anddimensions. 50 pages. E1.75
25 SIMPLE SHORT WAVEBROADCAST BAND AERIALS BP132E. M. NollDesigns for 25 different short wavebroadcast band aerials, from a simpledipole through helical designs to amulti -band umbrella. Information is
70 Practical Wireless, March 1993
also given on short wave bands,aerial directivity, time zones anddimension tables that will help spot anaerial on a particular frequency.63 pages. £1.95
25 SIMPLE TROPICAL AND MWBAND AERIALS BP145E M. NollSimple and inexpensive aerials for thebroadcast bands from medium waveto 49m. Information is also given onband details, directivity, time zonesand dimensions. 54 pages. E1.75
MORSE
INTRODUCING MORSE /A/Collected Articles from PW 19824985Ways of learning the Morse Code,followed by constructional details of avariety of keys including Iambic,Triambic and an Electronic Bug with a528 -bit memory as well as a practiceoscillator and Morse tutor.48 pages. E1.25
SECRET OF LEARNING MORSE CODE(THE) SOLMMark FrancisUpdates for the Novice Licence.Designed to make you proficient inMorse code in the shortest possibletime, this book points out many of thepitfalls that beset the student.84 pages. E4.95
SATELLITES
INTRODUCTION TO SATELLITETELEVISION (AN) BP195F. A. WilsonAnswers all kinds of questions aboutsatellite television. For the beginnerthinking about hiring or purchasing asatellite TV system there are details tohelp you along. For the engineer thereare technical details includingcalculations, formulae and tables.104 pages. 13.95
NEWNES GUIDE TO SATELLITE TVNGSTDerek StephensonThis book, the 2nd edition, is a hardbound volume, printed on high qualitypaper. The author is a satellite repairand installation engineer and the bookcovers all information needed by theinstallation engineer, the hobbyist andthe service engineer to understandthe theoretical and practical aspectsof satellite reception with dishinstallation and how to trouble -shootwhen picture quality is not up toanticipated reception. Mathematicshas been kept to a minimum.284 pages. E16.95
SATELLITE BOOK (THE) - A completeguide to satellite TV theory andpractice SBJohn BreedsThis book deals almost exclusivelywith television broadcast satellitesand is a comprehensive collection ofchapters on topics, each written by aexpert in that field. It appears to beaimed at the professional satellitesystem installer, for whom it isinvaluable, but it will be appreciatedby a much wider audience - anyoneinterested in satellite technology.280 pages. E30.00
SATELUTE EXPERIMENTER'SHANDBOOK (THE) 2nd Edition SEHMartin Davidoff K2UBCThe book is divided into four mainsections History, Getting Started,Technical Topics and Appendices. Itprovides information on spacecraftbuilt by, and for, radio amateurs. Inaddition, it discusses weather, TV -broadcast and other satellites ofinterest to amateurs. 313 pages E14.50
SATELUTE TELEVISION A layman'sguide STPeter PearsonPictures from space, that's whatsatellite television is all about.Orbiting satellites, 35000km high,receive TV signals from stations onthe earth and re -transmit them backagain. This book explains all you needto know to set up your own satelliteTV terminal at home, dish andaccessories, cable and tuner.73 pages. E1.00
SATELLITE TELEVISIONINSTALLATION GUIDE 2nd Ed STIGJohn BreedsA practical guide to satellitetelevision. Detailed guide -lines oninstalling and aligning dishes basedon practical experience.56 pages. £13.00
WEATHER SATELLITE HANDBOOK 4thedition WSHDr Ralph E. Taggart WB8DQTThis book explains all about weathersatellites, how they work and how youcan receive and decode their signalsto provide the fascinating pictures ofthe world's weather. Plenty of circuitdiagrams and satellite predictingprograms. 192 pages. E14.50
AMATEUR RADIO
ALL ABOUT VHF AMATEUR RADIOAAVAW. I. Orr W6SAIWritten in non -technical language,this book provides informationcovering important aspects of L!.h.f.radio and tells you where you can findadditional data. If you have a scanner,you'll find a lot of interesting signals inthe huge span of frequenciescovered, 100-300MHz & 50, 420, 902 &1250MHz bands. 163 pages. £9.50.
AMATEUR RADIO CALL BOOK )RSGB)1993 Edition ARCB93Over 60000 callsigns are listedincluding El stations. Nowincorporates a 122 -page section ofuseful information for amateur radioenthusiasts and a new novice callsignsection. 444 pages. E9.50
ARRL HANDBOOK FOR RADIOAMATEURS (THE) 1993 AHFR93This is the 70th edition of thishandbook and contains the bestinformation from previous issues.New for this edition is someinformation on feedback -loop designfor power supplies, a new gel -cellcharger project, updates on antennasystems and new coverage of baluns,propagation programs are comparedand colour SSTV and telephone FAXmachines are also covered. Finallythere's a new section on 'for theworkbench' with new projects for thereader to build. 1214 pages. E18.95
ARRL OPERATING MANUAL (THE)AOMAnother very useful ARRL book.Although written for the Americanamateur, this book will also be of useand interest to the UK amateur. Topicscovered range from short wavelistening through operating awards torepeaters, operating and satellites.684 pages. E12.95
ARRL SATELUTE ANTHOLOGY (THE)ASAThe best from the Amateur SatelliteNews column and articles out of 31issues of OSThave been gatheredtogether in this book. The latestinformation on OSCARs 9 through 13as well as the RS satellites isincluded. Operation on Phase 3satellites (OSCAR 10 and 13) iscovered in detail. 97 pages. E5.96
ARRL UHF/MICROWAVEEXPERIMENTER'S MANUAL(THE)AUMEVarious AuthorsA truly excellent manual for the keenmicrowave enthusiast and for thebudding 'microwaver'. Withcontributions from over 20 specialistauthors. Chapters coveringtechniques, theory, projects, methodsand mathematics. 446 pages. E14.50
COMPLETE DX'ER (THE) CDBob Locher W9KNIThis hook covers equipment andoperating techniques for the DXchaser, from beginner to advanced.Every significant aspect of DXing iscovered, from learning how to reallylisten, how to snatch the rare onesout of the pile-ups and how to securethat elusive QSL card.204 pages. 0.95
HINTS AND KINKS FOR THE RADIOAMATEUR HAKFEdited by Charles L Hutchinson andDavid NewkirkA collection of practical ideas
gleaned from the pages of OSTmagazine. Plenty of projects to build,hints and tips on interference, c.w.and operating and snippets ofinformation from amateurs who'vetried and tested the idea.129 pages. E4.95
INTRODUCTION TO AMATEURCOMMUNICATIONS SATELLITES (AN)BP290A. PickardThis book describes several currentlyavailable systems, their connection toan appropriate computer and howthey can be operated with suitablesoftware. The results of decodingsignals containing such informationas telemetry data and weatherpictures are demonstrated.102 pages. £3.95
INTRODUCTION TO AMATEUR RADIO(AN) BP257I. D. PooleThis book gives the newcomer acomprehensive and easy tounderstand guide through amateurradio. Topics include operatingprocedures, jargon, propagation andsetting up a station.150 pages. 13.50
INTRODUCTION TO RADIO WAVEPROPAGATION IAN) BP293J.G. LeeHow does the sun and sunspots affectthe propagation of the radio waveswhich are the basis of our hobby?They affect the ionosphere, butdiffering frequencies are treateddifferently. Find out how to use chartsto predict frequencies that will be themost profitable. What effect will noisehave on the signal? Find out with thisbook. 116 pages. £3.95
INTRODUCTION TO VHF/UHF FORRADIO AMATEURS (AN) BP281I.D. PooleAn excellent book to go with the newNovice or full callsign. Nine chaptersand an appendix deal with all aspectsand frequencies from 50 to 1300MHz.Topics include propagation,descriptions of the bands, antennas,receivers, transmitters and a specialchapter on scanners.102 pages. E3.50
PASSPORT TO AMATEUR RADIOPTARReprinted from PW1981-1982The famous series by GW3JGA, usedby thousands of successful RAEcandidates in their studies. Plus otheruseful articles for RAE studentsincluding emission codes,explanations of diodes, s.s.b. anddecibels. 87 pages. E1.50
PRACTICAL GUIDE TO PACKETOPERATION IN THE UK PGTPMike Mansfield G6AWDIntroduces the concept of packetradio to the beginner. Problem areasare discussed and suggestions madefor solutions to minimise them. Dealswith the technical aspects of packettaking the reader through setting upand provides a comprehensive guideto essential reference material.205 pages. £8.95
PRACTICAL IDEAS FOR RADIOAMATEURS PIFRIan Poole G3YWXThe 1992 Offers a wealth of hints, tipsand general practical advice for alltransmitting amateurs and short wavelisteners. 128 pages £5.95
GRP CLASSICS DCEdited by Bob Schetgen KU7GOperating QRP is fun. The equipmentis generally simple and easy to build,but often performs like moresophisticated commercial equipment.Some QRP Field Day stations operatea full 27 hours on a car battery. it'sthe perfect equipment for emergencycommunication when the power fails.Extracts from OST and the ARRLHandbook. 274 pages E9.95
RADIO AMATEUR CALLBOOKINTERNATIONAL LISTINGS 1993 71stEdition RAC192The only publication listing licensedradio amateurs throughout the world.Also includes DXCC Countries list,standard time chart, beacon lists andmuch more.Over 1400 pages. E19.50
RADIO AMATEUR CALLBOOK NORTHAMERICAN LISTINGS 1993 71stEdition RACN92Listings of US amateurs (includingHawaii). Also contains standard timechart, census of amateur licences ofthe world, world-wide (1SL bureau,etc. Over 1400 pages. E19.50
RADIO AMATEUR'S QUESTIONS &ANSWER REFERENCE MANUAL)THE)4th Edition. RADAR. E. G. Petri G8CCJThis book has been compiledespecially for students of the City andGuilds of London Institute RAE. It isstructured with carefully selectedmultiple choice questions, to progresswith any recognised course ofinstruction, although is is not intendedas a text book.280 pages. 0.95
RAE MANUAL (THE) RSGB RAEMG.LBenbow G3HBThe latest edition of the standard aidto studying for the Radio Amateurs'Examination. Updated to cover thelatest revisions to the syllabus. Takesthe candidate step-by-step throughthe course.127 pages. £6.70
W1FB's DESIGN NOTEBOOK WONDoug DeMAW W1FBThis book is aimed at the non-technical amateur who wants to buildsimple projects and obtain a basicunderstanding of amateur electronics.Your workshop does not need to beequipped like an engineering lab to besuccessful as an experimenter. Don'tlet a lack of test equipment keep youfrom enjoying the thrills ofexperimentation.195 pages E8.50
MEWS HELP FOR NEW HAMS WHFHDoug DeMaw W1FBThis book covers everything fromgetting acquainted with newequipment to constructing antennas,station layout, interference andoperating problems to on -the -airconduct and procedures.155 pages E6.95
WI FB's GRP NOTEBOOK WOM2nd EditionDoug De Maw W1FBThe new improved and updated 2ndedition of this book, covers theintroduction to QRP, constructionmethods, receivers and transmittersfor QRP. This workshop -notebookstyle publication, which is packedwith new designs for the keen GRPoperator, also covers techniques,accessories and has a small technicalreference section.175 pages. E7.95
YOUR GATEWAY TO PACKET RADIOYGTPStan Horzepe WA1LOUWhat is packet radio good for andwhat uses does it have for the'average' amateur? What areprotocols? where, why, when? Lots ofthe most asked questions areanswered in this useful book. Itincluded details of networking andspace communications using packet.278 pages. E8.95
THEORY
ARRL ELECTRONICS DATA BOOK(THE) AEOBDoug OeMaw W1FBBack by popular demand, completelyrevised and expanded, this is a handyreference book for the r.f. designer,technician, amateur andexperimenter. Topics includecomponents and materials, inductorsand transformers, networks & filters,digital basics and antennas andtransmission lines. 260 pages. E8.95
AUDIO (Elements of electronics -book 6) BP111F A. WilsonThis book studies sound and hearing,and examines the operation ofmicrophones, loudspeakers,amplifiers, oscillators, and both diskand magnetic recording. Intended togive the reader a good understandingof the subject without getting involvedin the more complicated theory andmathematics.308 pages. 13.95
BEGINNERS GUIDE TO MODERNELECTRONIC COMPONENTS (A)BP285R.A. PenfoldThis book covers a wide range ofmodern components. The basicfunctions of the components aredescribed, but this is not a book onelectronic theory and does notassume the reader has an in-depthknowledge of electronics. It isconcerned with practical aspectssuch as colour codes, decipheringcode numbers and the suitability.166 pages. E3.95
EVERYDAY ELECTRONICS DATABOOK EEDBMike Tooley BAThis book is an invaluable source ofinformation of everyday relevance inthe world of electronics. It containsnot only sections which deal with theessential theory of electronic circuits,but it also deals with a wide range ofpractical electronic applications.250 pages. E8.95
FILTER HANDBOOK A practicaldesign guide FHStefan NiewiadomskiA practical book, describing thedesign process as applied to filters ofall types. Includes practical examplesand BASIC programs. Topics includepassive and active filters, workedexamples of filter design, switchedcapacitor and switched resistor filtersand includes a comprehensivecatalogue of pm -calculated tables.195 pages. 130.00
FROM ATOMS TO AMPERES BP254F.A.WilsonExplains in simple terms the absolutefundamentals behind electricity andelectronics. Topics include the use ofSI units, gravity, magnetism, light, theelectron, conduction in solids andelectrical generators. 244 pages. 13.50
PRACTICAL ELECTRONICSCALCULATIONS AND FORMULAEBP53F. A. WilsonThis has been written as a workshopmanual for the electronics enthusiast.There is a strong practical bias andhigher mathematics have beenavoided where possible.249 pages. 0/P
REFLECTIONS Transmission Lines &Antennas RTLAM.Walter Maxwell W2DUThis will help dispel the half-truthsand outright myths that many peoplebelieve are true about transmissionlines, standing waves, antennamatching, reflected power andantenna tuners. 323 pages. £14.50
SOLID STATE DESIGN FOR THE RADIOAMATEUR SSDFLes Hayward W1ZOI and DougDeMaw W1FBBack in print by popular demand! Arevised and corrected edition of thisuseful reference book covering allaspects of solid-state design. Topicsinclude transmitter design, poweramplifiers and matching networks,receiver design, test equipment andportable gear. 256 pages E10.95
TRANSMISSION UNETRANSFORMERS TLTJerry Sevick W2FMIThis is the second edition of this book,which covers a most intriguing andconfusing area of the hobby. It shouldenable anyone with a modicum of skillto make a balun, etc. Topics includeanalysis, characterisation,transformer parameters, baluns,multimatch transformers and simpletest equipment. 270 pages. E13.50
RADIO
AIR & METED CODE MANUAL 12thEdition AAMC12Joerg KlingenfussDetailed descriptions of the WorldMeteorological Organisation GlobalTelecommunication System operatingFAX and RTTY meteo stations, and itsmessage format with decodingexamples. Also detailed description ofthe Aeronautical FixedTelecommunication Network amongstothers. 358 pages £18.00
Practical Wireless, March 1993 71
HIGH POWER WIRELESS EQUIPMENTArticles from Practical Electricity1910-11 HPWEEdited by Henry Walter YoungA reprint of interesting practicalarticles from the very early days ofradio, when materials and methodsdescribed are from another era.Subjects covered ranges from aerialsthrough detectors to things like Teslaand his wireless age. 99 pages. £6.85
PASSPORT TO WORLD BAND RADIO1993 PEWB93This book gives you the information toexplore and enjoy the world ofbroadcast band listening. It includesfeatures on different internationalradio stations, receiver reviews andadvice as well as the hours andlanguage of broadcast stations byfrequency. The 'blue pages' provide achannel -to -channel guide to worldband schedules. 416 pages. E14.50.
RADIOTELETYPE CODE MANUAL 12thEdition RCM12Joerg KlingenfussThis book gives detailed descriptionsof the characteristics of telegraphtransmission on short waves, with allcommercial modulation typesincluding voice frequency telegraphyand comprehensive information on allAlly systems and c.w. alphabets.96 pages. £11.00
RESCUE RPaul Beaver & Paul BerriesThis book follows the life andconditions of rescue helicoptercrews. This is not drama, this is reallife and it makes a true impression ofthe rescue services for the reader.There are transcriptions of air/groundand between crew dialogues, asummary of the main distress andrescue radio frequencies andhelicopter base locations.192 pages. £9.99
SCANNERS (Third Edition) SPeter Rouse GU1DKDA guide for users of scanningreceivers, covering hardware,antennas, accessories, frequencyallocations and operating procedures.245 pages. 0/P
SCANNERS 2 S2Peter Rouse GU1DKDThe companion to Scanners, thisprovides even more information onthe use of the v.h.f. and u.h.f.communications band and givesconstructional details for accessoriesto improve the performance ofscanning equipment. 261 pages.£10.95
SHORT WAVE COMMUNICATIONSSWC. Peter Rouse GUIDOCovers a very wide area and soprovides an ideal introduction to thehobby of radio communications.International frequency listings foraviation, marine, military, spacelaunches, search and rescue, etc.Chapters on basic radio propagation,how to work your radio and what thecontrols do, antennas and band plans.187 pages. £8.95
SHORT WAVE RADIO LISTENERS'HANDBOOK SWRLArthur MillerIn easy -to -read, non -technicallanguage, the author guides thereader through the mysteries ofamateur, broadcast and CBtransmissions. Topics coverequipment needed, identification ofstations heard & the peculiarities ofthe various bands. 207 pages. £7.99
WORLDWIDE HF RADIO HANDBOOKWHRHMartyn R. CookeThis book lists high frequencies usedby aircraft and aeronautical groundstations. Divided into sections,
Military, Civil, etc. The book should beeasy to use. 124 pages. £6.95
1934 OFFICIAL SHORT WAVE RADIOMANUAL OSWREdited by Hugo GernsbackA fascinating reprint from a bygoneage with a directory of all the 1934s.w. receivers, servicing information,constructional projects, circuits andideas on building vintage radio setswith modern parts. 260 pages. £10.15
BEGINNERS
BEGINNER'S GUIDE TO RADIO 9thEdition BGTRGordon J. KingThe book takes you in logical stepsfrom the theory of electricity andmagnetism to the sound you hearfrom the loudspeaker. Radio signals,transmitters, receivers, antennas,components, valves &semiconductors, CB & amateur radioare all dealt with . 266 pages. E14.95
ELECTRONICS SIMPLIFIED - CRYSTALSET CONSTRUCTION BP92F. A. WilsonEspecially written for those who wishto take part in basic radio building. Allthe sets in the book are old designsupdated with modern components. Itis designed for all ages upwards fromthe day when one can readintelligently and handle simple tools.72 pages. £1.75
SIMPLE ELECTRONICS CIRCUIT ANDCOMPONENTS Book One (THE) BP62The aim of this book is to provide anin -expensive but comprehensiveintroduction to modern electronics.209 pages. £3.50
INTERFERENCE
INTERFERENCE HANDBOOK (USA) IHWilliam R. Nelson WA6FQGHow to locate & cure for radioamateurs, CBers, TV & stereoowners. Types of interferencecovered are spark discharge,electrostatic, power line many 'cures'are suggested. 250 pages. £9.50
DATA REFERENCE
INTERNATIONAL TRANSISTOREQUIVALENTS GUIDE BP85A. MichaelsPossible substitutes for a popularselection of European, American andJapanese transistors and includesdevices produced by over 100manufacturers. 299 pages. £3.95
NEWNES AUDIO & HI -Fl ENGINEER'SPOCKET BOOK NAHEVivian CapelThis is a concise collection ofpractical and relevant data for anyoneworking on sound systems. The topicscovered include microphones,gramophones, CDs to name a few.190 pages. Hardback £10.95
NEWNES COMPUTER ENGINEER'SPOCKET BOOK NCEPThis is an invaluable compendium offacts, figures, circuits and data and isindispensable to the designer,student, service engineer and allthose interested in computer andmicroprocessor systems.255 pages. Hardback £10.95
NEWNES ELECTRONICS POCKETBOOK 5th Edition NEPBPresenting all aspects of electronicsin a readable and largely non -mathematical form for both theenthusiast and the professionalengineer.315 pages. Hardback £10.95
NEWNES RADIO AMATEUR ANDLISTENER'S POCKET BOOK NRAASteve Money G3FZXThis book is a collection of useful andintriguing data for the traditional andmodern amateur as well as the s.w.l.Topics such as AMTOR, packet radio,SSTV, computer communications andmaritime communications are allcovered. 160 pages hardback. £10.95
NEWNES RADIO AND ELECTRONICSENGINEER'S POCKET BOOK 18thEdition NRAEKeith BrindleyUseful data covering math,abbreviations, codes, symbols,frequency bands/allocations, UKbroadcasting stations, semi-conductors, components, etc.325 pages hardback £9.95
POWER SELECTOR GUIDE BP235J. C. J. Van de VenThis guide has the information on allkinds of power devices in usefulcategories (other than the usual alphanumeric sort) such as voltage andpower properties making selection ofreplacements easier.160 pages. £4.95
FAULT FINDING
ARE THE VOLTAGES CORRECT? ATVCReprinted from PW 1982-1983How to use a multi -meter to fault -findon electronic and radio equipment,from simple resistive dividers throughcircuits using diodes, transistors, i.c.sand valves. 44 pages. E1.50
GETTING THE MOST FROM YOURMULTIMETER BP239R. A. PenfoldThis book is primarily aimed atbeginners. It covers both analogueand digital multi -meters and theirrespective limitations. All kinds oftesting is explained too. No previousknowledge is required or assumed.102 pages. £2.95
HOW TO USE OSCILLOSCOPES &OTHER TEST EQUIPMENT BP267R.A. PenfoldHints and ideas on how to use the testequipment you have, to check out, orfault find on electronic circuits. Manydiagrams of typical waveforms andcircuits, including descriptions ofwhat waveform to expect withparticular faults, or distortion in audioamplifiers. 104 pages. £3.50
MORE ADVANCED TEST EQUIPMENTCONSTRUCTION BP249R.A. PenfoldA follow on from Test EquipmentConstruction fl3P248)this book looksat digital methods of measuringresistance, voltage, current,capacitance and frequency. Alsocovered is testing semi -conductors,along with test gear for general radiorelated topics. 102 pages. £3.50
MORE ADVANCED USES OF THEMULTIMETER BP265R.A. PenfoldThis book is primarily intended as afollow-up to BP239, Getting the mostfrom your Multi -meter. By using thetechniques described in this book youcan test and analyse the performanceof a range of components with just amulti -meter (plus a very fewinexpensive components in somecases). The simple add-ons describedextend the capabilities of a multi -meter to make it even more useful.96 pages. £2.95.
OSCILLOSCOPES, HOW TO USETHEM, HOW THEY WORK 3rd Edition011111
Ian HickmanThis book describes oscilloscopesranging from basic to advanced
models and the accessories to gowith them. Oscilloscopes areessential tools for checking circuitoperation and diagnosing faults, andan enormous range of models isavailable. 248 pages E14.95
TELEVISION
AN COMPENDIUM (THE) ATVCMike Wooding 6610MThis book is for those interested inamateur television, particularly thehome construction aspect. There isnot a 70cm section as the author feltthis is covered in other books. Otherfields, such as 3cm TV, are covered indepth. A must for the practical ANenthusiast. 104 pages. £3.00
GUIDE TO WORLD-WIDE TELEVISIONTEST CARDS GTWTEdition 3Keith Hamer & Garry SmithCompletely revised and expanded,this is a very handy and usefulreference book for the DXTVenthusiast. Over 200 photographs ofTest Cards, logos, etc., world wide.60 pages. £4.95
CONSTRUCTION
ADVANCED SHORT WAVE SUPERHETRECEIVER CONSTRUCTION BP276R.A. PenfoldA general purpose receiver to build,from antenna to audio, described inunderstandable English. Topicsinclude switched mode powersupplies, precision regulators, dualtracking regulators and computercontrolled supplies. 92 pages. 1295
COIL DESIGN AND CONTRUCTIONMANUAL BP160B.B. BabaniCovering audio to r.f. frequencies, thisbook has designs for almosteverything. Sections cover suchtopics as mains and audio outputtransformers, chokes and r.f. coils.What is the required turns ratio? Thisbook will show you how to find out.Text and tables. 106 pages. 12.50
HOW TO DESIGN AND MAKE YOUROWN PCBs BP121R. A. PenfoldThe purpose of this book is tofamiliarise the reader with bothsimple and more sophisticatedmethods of producing p.c.b.s. Theemphasis of the book is very much onthe practical aspects of p.c.b. designand construction.66 pages. E2.50
MORE ADVANCED POWER SUPPLYPROJECTS BP192R. A. PenfoldThe practical and theoretical aspectsof the circuits are covered in somedetail. Topics include switched modepower supplies, precision regulators,dual tracking regulators andcomputer controlled power supplies,etc. 92 pages. £2.95
POWER SUPPLY PROJECTS BP76R. A. PenfoldThis book gives a number of powersupply designs including simpleunstabilised types, fixed voltageregulated types and variable voltagestabilised designs.89 pages. E2.50
RADIO/ TECH MODIFICATIONSNUMBER 3 RTM3This book is intended as a referenceguide for the experienced radiotechnician. Produced for the USmarket it contains modificationinstructions for a wide variety ofscanners, CB rigs and amateurequipment including Alinco, loom,Kenwood, Yaesu and other makes.
160 pages. £9.95
TEST EQUIPMENT CONSTRUCTIONBP248R.A.PenfoldDescribes, in detail, how to constructsome simple and inexpensive, butextremely useful, pieces of testequipment. Stripboard layouts areprovided for all designs, together withwiring diagrams where appropriate,plus notes on their construction anduse. 104 pages. £2.95
50 (FET) FIELD EFFECT TRANSISTORPROJECTS BP39F.G.Rayer50 circuits for the s.w.l., radioamateur, experimenter or audioenthusiast using te.ts. Projectsinclude r.f. amplifiers and converters,test equipment and receiver aids,tuners, receivers, mixers and tonecontrols. 104 pages. £2.95
COMPUTING
INTRODUCTION TO COMPUTERCOMMUNICATIONS (AN) BP177R. A. PenfoldDetails of various types of modem andtheir applications, plus how tointerconnect computers, modems andthe telephone system. Alsonetworking systems and RTTY.72 pages. £2.95
NEWNES AMATEUR RADIOCOMPUTING HAND BOOK NARCJoe Pritchard GIUQWShows how radio amateurs andlisteners can 'listen' to signals byreading text on a computer screen.This book also covers the applicationof computers to radio 'housekeeping'such as log -keeping, QSL cards,satellite predictions and antennadesign as well as showing how tocontrol a radio with a computer.363 pages. £15.95
MAPS
NORTH ATLANTIC ROUTE CHARTNARCThis is a five -colour chart designedfor the use of ATC in monitoringtransatlantic flights. Supplied folded.740 x 520mm. £5.50
QTH LOCATOR MAP QLMThis full colour map has beenproduced by members of one of theHungarian Amateur Radio Clubs forv.h.f. and Oil amateurs in Europe.The map is based on the MaidenheadLocator System and also the mainv.h.f. and u.h.f. beacons with theirlocator, power output, height abovesea level and modulation system.970 x 670mm. £5.95
RADIO AMATEUR'S MAP OF NORTHAMERICA (USA) RAMOShows radio amateur prefixboundaries, continental boundariesand zone boundaries.760 x 636mm. £3.50
RADIO AMATEUR'S PREFIX MAP OFTHE WORLD (USA) RAPMShowing prefixes and countries, pluslistings by order of country and ofprefix. 1014 x 711mm. 0/P
72 Practical Wireless, March 1993
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Miscellaneous
DIY Inexpensive radio projects. Easy to make. SAE.RYLANDS, 39 Parkside Avenue, Southampton S019AF.
For Sale
VALVES GALORE Most valves available from stock.Otherwise obtained quickly. Please send SAE statingrequirements or telephone. VALVE & ELECTRONICSUPPLIES Chevet Books, 157 Dickson Road, BlackpoolFY1 2EU. Tel: (0253) 751858.
HAMS 4 HAMS: Ex-PMR. The cheap route onto VHF.Pye M294 (25 watt, crystal controlled, ideal for packet)2M or 4M from £38.00 (conversion in HRT Jan '93).Storno 644 Synthesised from £24.00, (conversion in HRTAug '92) Crystal type from £16.50. For full price list andordering details, please send SAE to Hams 4 Hams, 4Granville Avenue, Newport, Shropshire, TF10 7DX.
SOLARTRON double -beam oscilloscopes, choiceCD140OR's with various modules £50/E75 com plete. Alsotelequipment D43. Medelec for 1002 fibre optic recorder,cost £2,000, CRT now £600. Offers? All working. Tel:(0483) 505504.
JAPANESE SEMICONDUCTORS and TransmittingTubes for broadcasting, communication and industrialuse. Quotation sent on request. TSUTOM YOSHIHARA,OSAKA, JAPAN Fax: 81-6-338-3381
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74 Practical Wireless, March 1993
Wanted
TESTGEAR, Computers, Computer Surplus,Amateur.Bought for cash. 104251 274274
WANTED VALVES ESP. KT66, KT88, PX4, PX25,Klystrons, Magnetrons, Transistors, I.C.s, Plugs, Sock-ets. If possible send written list - we reply same day.Cash waiting. BILLINGTON VALVES, Oakendene In-dustrial Estate, Near Horsham RH138AZ. Callers pleasephone for appointment. Te1:(0403) 865105. FAX: 10403)865106. Telex: 87271.
WANTED Grundig Satellit 2100 radio. Must be inperfect condition. Tel: 107421 668037.
WANTED Pair of 4 K ohm earphones, preferably S.G.Brown. Tel: 051-264 9313 (after 6 pm).
Receivers
TRANSCIEVER PRC 316 HF AM CW 4 watts outputwith speaker/mic and manual £135.00. C13 HF set £100.Pye boot mount Westminsters, 30 watts 4M AM withharness, £20. All prices include P&P. Send SAE for list.CP Surplus, 56A Worcester Street, WolverhamptonWV2 4LL. Tel: (0902) 20315.
Holidays
CHALET Sleeps 2 + 2. Elevated rural position. Coastalview. Pets. Goats. Tel: (08401 212262.
FLORIDA Gulf Coast. Two luxury villas. Private beach,pools, water frontage, golf course. Sleeps six. £350p.w. G1GTO. Tel: (0493) 655068.
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IS YOUR CLUBPLANNING ORHOLDING AN
EVENT OR RALLY?
Telephone (0202)659920 to find out the
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Radio Clubs .
VALVES VALVES VALVESThe following valves in matched pairs 6JSC, 6KD6, 6JE/A, 6L06, 6HF5, 6146A,61468, yes the 6JS6/C is Japanese and works in the FT101. Most amateur radiovalves including difficult to obtain types ex stock. Quotations without obligation pleaseenquire. Remember over 200 types ex stock. SAE for list. Phone for assistance retypes suitable for your equipment. USA and Jap manufacture of popular type available.
PHONE 0484 654650 or 420774 FAX 0484 655699WILSON VALVES (Prop. Jim Fish G4MH) visa
28 Banks Ave, Golcar, Huddersfield HD7 4LZ
ADVERTISERS INDEXAA&A 51 GROSVENOR 52 QUARTSLAB MARKETING 54
A H SUPPLIES 66 HAYDON COMMUNICATIONS .51 RADIO SHACK 76
AOR(UK) 58 HOLDINGS AMATEUR 68 RAS NOTTINGHAM 58
AERIAL TECHNIQUES 66 ICOM (UK) COVER iii,11 REG WARD 12
AMATEUR RADIO COMMS. 67 J & P ELECTRONICS 58 RSGB 68
BILLINGTON EXPORT 68 KENWOOD 29,31,40 RST VALVES 66
BIRKETT 66 LAKE ELECTRONICS 66 SMC COVER ii
BREDHURST ELECTRONICS 40 LEE ELECTRONICS 2 SRP TRADING 12
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DATONG 44 MARTIN LYNCH 8,9 SYSTEMS 10
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ESSEX AMATEUR PETER RODMELL 54 TENNAMAST 58
RADIO SERVICES 44 PHOTO ACOUSTICS 4 WATERS & STANTON 5,6,7
G-MEX RALLY 10 PRACTICAL MOTORIST 63 WILSON VALVES 75
Practical Wireless, March 1993 75
Tuun LU%MLSOUTH WALES SOUTHAMPTON PORTSMOUTH DERBYSHIRE
ELECTRO MARTReceivers, Scanners, Howes, ERA,
South MidlandsCommunications
NevadaCommunications
RILEY'S T.V. SERVICES LTD.SUPPLIERS OF: -
SCANNERS - C.B. 27-934 MHz -CB, Marine radio etc. part exchange Visit our showrooms for Icom, Kenwood, amateur AERIALS - TEST METERS - TOOLS -
welcome.
Full Service & Repair Facilities
96 High St, Clydach,
Official Yaesu ImporterS.M. House, School Close,
Chandlers Ford Industrial Estate,
radio products and a large range of scanningreceivers. New and part exchange welcome.
189 London Road,North End, Portsmouth,
TELEPHONES KITS AND CABLES
125 LANGWITH ROADHILLSTOWN
CHESTERFIELD S44 6LXSwansea Eastleigh, Hants S05 3BY. Hants, P02 9AE PHONE 0246 826578
Tel: 0792 842135 Tel: 0703 255111 Tel: 0705 662145 CLOSED WEDNESDAY
HERNE BAY0ICOM
ICOM (UK) LIMITEDThe Official Icom Importer
Unit 8, Sea StreetHerne Bay, Kent CT6 8LD
Tel: 0227 741741Fax: 0227 360 155
Open Mon -Fri 9am-5.30pm (Lunch 1-2)
BUCKINGHAMSHIRE
Photo -Acoustics Ltd.Approved Kenwood, Yaesu and
Icom dealer (part exchangealways welcome)
58 High Street, Newport Pagnell,Buckinghamshire MK16 8A0
Tel: 0908 610625
(Mon -Fri 9.30-5.30, Sat 9.30-4.30)
CORNWALL 24-lat 7 days a week
SKYWAVERADIO AMATEUR AND MARINECOMMUNICATIONS SERVICES
ICOM, YAESU, NAVICO,JAYBEAM, etc.
Slades Road, St. Austell,Cornwall PL25 4HG
Tel: 0726 70220Voice Bank: 0426 961909
SCOTLAND
JAYCEEELECTRONICS LTD
20 Woodside Way, Glenrothes, Fife KY7 5DFTel: 0592 756962 (Day or Night)
Fax No. (0592) 610451
Open. Tues-Fn 9-5. Sat 9-4
MENWOOD, YAESU & ICOM APPROVED DEALERS
A good stock of new and secondhandequipment always in stock
TYNE + WEAR
SUPERTECHCommunications Specialists
YUPITERU SONY.AOR PAPA
Official Nevada and Kernow stockists
Full range of CBs,Scanners + Accessories
Mail Order -Branches throughout the North East
32 RUSSELL Way
GATESHEAD METRO CENTRE NEll 9YZ
TEL: (091) 4932316
Open: Monday -Friday 10am - 8pmThursday 10am - 9pmSaturday 9am - 7pm
IRELAND
ML.DOCEMIROMOE1100
All your requirements under one roof
RECEIVERS -TRANSCEIVERS -ACCESSORIES
Open Monday -Saturday 9am-5.30pm
Midleton Enterprise Park, Midleton,County Cork 021/632725 + 613241
Contact Lynnon the
AdvertisingHotline
(0202) 659920
KENT
KANCA PRODUCTSFor QRP kits
A variety of kits for RECEIVERS,TRANSMITTERS & TEST GEAR.
Send an A5 SAE for a free copyof our catalogue
3. Limes Road. Folkestone KENT CT19 4AUTel/Fax 0303 276171 0900 - 1900 Only
DEVON
Reg. Ward & Co. Ltd.The South -West's largest amateur radiostockist. Approved dealer for Kenwood,
Yaesu and Icom
1 Western Parade,West Street, Axminster,
Devon, EX13 5NYTel: 0297 34918
(Closed 1.00-2.00 and all day Monday)
YORKSHIRE YAESUICOM
Kenwood
Alan HookerRadio Communications42, Netherhall Road, Doncaster
Tel: 0302 325690
Open Mon -Sat 10-5pmClosed Thursdays
WEST SUSSEX reDER
BREDHURSTELECTRONICS LTD.
High St., Handcross, West SussexTel: (0444) 400786Fax: (0444) 400604
Situated at the Southern end of M23.
wC Easy access to M25 andSouth London.
Open Mon -Fri 9am-5pmSat 9.30am-4.30pm.
YAESU
ICOM
Access RADIO SHACKALL OF THE EQUIPMENT WE SELL HAS BEEN IMPORTED BY
THE FACTORY AUTHORISED DISTRIBUTORS WITH FULLWARRANTY BACK-UP AND PARTS SERVICE.
KENWOOD TS -850SThe latest transceiver from this famous stable
Lowe HF-225Kenwood R-2000
High performance compact receiver10 Memories
£425.00£595.00
TS -850S SUPERB SPECIFICATIONSKenwood VC -10 VHF converter for R-2000 £161.00 Creating a new era in Amateur Radio!Kenwood R-5000 Top of their range receiver £875.00 Call us for the latest details and stock position, also forKenwood VC -20Yaesu FRG8800
VHF converter for R-5000Fine performing all mode set
£167.00£640.00
any other model from
Yaesu FRV-8800 VHF converter for above £100.00 KENWOOD ICOM YAESUIcom IC-R71E The old favourite £855.00 Scanners by AOR, Fairmate, Jupiter, Icom, Realistic,Icom IC-R72E Icom's latest, small & excellent £645.00Icom IC -R9000 The set with everything £3995.00 Bearcat to name but a few.JRC-535 The latest from Japan Radio Company £1095.00 Competitive service and prices.Drake RR -3 Second-hand high specification set £1595.00
RADIO SHACK 188 BROADHURST GARDENS,LONDON NW6 3AY
(Just around the corner from West Hampstead Station on the Jubilee Line)Giro Account No. 588 7151 Fax: 071-328 5066 Telephone: 071-624 7174
We will be pleased toquote you for anythingyou require in thecommunications orcomputer field. Inorder to avoid a greatdeal of time wastingon both our parts, wenow deal with callersby appointment. Weare pleased to hearfrom you and see you,and we aim to giveyou the attention youdeserve, so pleasecall us first,73s Terry EdwardsG3STS
Access
76 Practical Wireless, March 1993
I C -781Weare definitely talking flagships here,
The IC -781 is technical excellencewithout compromise, a master -model HF all -bandtransceiver that all Amateurs aspire to. Features(short list) include: 5" CRT central information display,spectrum scope, twin passband tuning, dual -watch,auto -antenna tuning, 105dB dynamic range, DDS, 99memor channels and .150W of output power!
_73The size and weight of ICOM's IC -735
%./ HF transceiver make it ideal for bothase-station and mobile operations. The IC -735 has a
105dB dynamic range, passband tuning, noiseblanker, 12 memory channels, CW full/semi break-inplus attenuator and preamp. Optional featuresinclude an electronic keyer and auto -antenna tuner.bee why the IC -735 is as popular today as it ever was.
IC -720A 50MHz/HF transceiver that allows7 you to discover the fun that can be
had worldwide on the increasingly popular 50MHzband. Features include: 1.8-50MHz, simple all -modeoperation, compact size, AF speech compressor,passband tuning, DDS, 105dB dynamic range and
and stacking registers. 30kHz-33MHz and 46.2-61.1 MHz Rx is possible but not guaranteed.
I C-765DX enthusiasts will love this HF all -bander. By using the DFM (Direct
Feed Mixer) the Rx circuit ensures 105dB dynamicrange and a high +23dBm intercept point allowingweak signals to be received even duringcompetition. Other features include: auto -antennatuning with tuning data memory, Built-in CW narrowfilter (500Hz to -6dB, CW pitch control and IF shift.
IC -737 This is ICOM's latest HF transceiver, acompact design using state-of-the-
art technology to introduce for the first time; memopad, DBSR, auto -antenna selector and quick splitfunctions. These new functions will excite HFbeginners who want to take the next step up andusers keen on portable or mobile operations. The IC -737 is an ideal transceiver for taking on the DX world.
'-' MI MI
- -
ICOM manu acture a full range of Amateur base -stations, transceiversand receivers capable of operating on all popular frequencies andbeyond. No matter what your requirement ICOM have the radio for you.
For more information and location of your local Icom dealer contact:Icom (UK) Ltd. Dept PW Sea Street Herne Bay Kent CT6 8LD
Telephone: 0227 741741 (24hr). Fax: 0227 741742
;;Topward 20MHz SOPHISTICATEDOSCILLOSCOPE 7025
GL29G
YOU WILL ALWAYS FIND MONEY SAVING BARGAINS
AND LOW PRICES AT MAPLIN ELECTRONICS
SAVE UP TO *E100ON OSCILLOSCOPES
Due to Maplin's continued success and the popularity of oursuperb range of oscilloscopes, we are able to offer them atSPECIALLY REDUCED PRICES, but they are only available atthese prices AT MAPLIN STORES for a LIMITED PERIOD, sohurry down to your nearest Maplin store TODAY! Advanceddesign and high quality manufacturing techniques have beencombined to bring you, at a sensible price, all the features thatyou would expect of a sophisticated oscilloscope. For example,I mV/div sensitivity, advanced 6 -inch CRTwith percentage markers and an internalgraticule that eliminates parallax error,ensuring a highly accurate display, and an X -Ymode that produces Lissajous patterns forphase shift measurements. Type 7025 has allthe features required for general purpose useand can display signals from DC to at least20MHz with a high degree of accuracy. Inaddition to all the features of the 7025, Type7026, has the added facility of a delayed
SAVE £100 7025 (GL29G) Catalogue Price £299.95SAVE £20 7026 (GL3OH) Catalogue Price £349.95
SAVE £70 7045 (GL31J) Catalogue Price £449.95SAVE £40 7046 (GL33L) Catalogue Price £499.95
sweep timebase, which can be used to magnify a portion of awaveform, making possible, accurate time interval measure-ments and the study of short duration events. The sophisticatedType 7045, has a bandwidth of 40MHz and incorporates a 4Onsdelay line to enable the display of very short duration events intheir entirety. Top -of -the -range is the Type 7046, a delayedsweep oscilloscope with increased magnification along with a40MHz bandwidth and capable of displaying complex signals
with precision and accuracy.
* Please note: MONEY SAVINGBARGAINS SHOWN ON THIS PAGEare applicable to purchases made inMAPLIN STORES ONLY and are notavailable at these prices throughMail Order.
NOW £199.95NOW £329.95NOW £379.95NOW £459.95
Rush to your local Maplin store: BIRMINGHAM; Sutton New Road, Erdington. BRIGHTON; 65 London Road. BRISTOL;302 Gloucester Road. CARDIFF; 29-31 City Road. CHATHAM; 2 Luton Road. COVENTRY; 12 Bishop Street.EDINBURGH; 126 Dairy Road. GLASGOW; 264-266 Great Western Road. ILFORD; 302-304 Green Lane. LEEDS;Carpet World Building, 3 Regent Street. LEICESTER; Office World Building, Burton Street. LONDON; 146-148 Burnt OakBroadway. Edgeware. 107-113 Stanstead Road, Forest Hill. 120-122 King Street, Hammersmith. MANCHESTER;8 Oxford Road. NEWCASTLE-UPON-TYNE; Unit 4, Allison Court, The Metro Centre, Gateshead. NOTTINGHAM; 86-88Lower Parliament Street. PORTSMOUTH; 98-100 Kingston Road. READING; 129-131 Oxford Road. SHEFFIELD; 413Langsett Road, Hillsborough. SOUTHAMPTON; 46-48 Bevois Valley Road. SOUTHEND-ON-SEA; 282-284 LondonRoad, Westcliff. Plus a NEW STORE opening soon in MIDDLESBROUGH. Phone 0702 552911 for further details. Allitems are subject to availability. All prices include VAT. Offer ends July 31st 1993. ELECTRONICS
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