COMPUTING IN RADIO 3eaturing

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reMAY 1995 P.90

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NOW ON THE INTERNET!

COMPUTING IN RADIO3eaturingBits & Bytes Special

Choosing & Using Your Computer

Amateur Radio and The Internet

+ COMPETITION

CLUB SPOTLIGHT

+ NOVICE NATTER

ANTENNA WORKSHOP

9 7 1410

0850 2

0 5 >

neviewedThe Yaesu

FT -51R

/3/ofildPart 3 of the PWMartlet 70MHzTransceiver project

Dual Band Handheld FT-n ROnly one DialNolume knob

required for easier use

Threedual receive

configure -

lions41-1F NAiF

11.111F. o

VIAFIUlifwilt\ main

band

frequencyon right

or lett side

Flexibleprogramming

ailows

ain or sub bandtransmit on

m

IMS.r1UrsiJ

so-rr,L1411\

An 8 character ratalpha-numenc

user helpmenu scrolls opeion

instructionsin the bottom

of the

large backlitdisplay

MH-29A2BLCD Display Micwith RemoteFunctions(Optional)

The new FT -51RDual Band HT isstate-of-the-art,and easy to use!

So easy, you won't need an operatingmanual. Its exclusive, scrolling instruc-tion menu located in the large, backlitdisplay "window", guides you throughtotal operation while simultaneouslyviewing the main display window.

You'll like some of the other new,exclusive features, too. Like SpectrascopeThis unique feature displays real time,continuous scanning of activityon adjacent frequencies in VFOmode or 8 of your favourite

"I can see two frequenciesand alpha -numeric all at thesame time.'

"Scrolling instructions tell mewhat to do next'"

Spectrascope"displays

active

adiacentfrequencies

is real time

with relativesignal stre

l batteryvoltage

readout

Digitaaisplys condition

of batteryin

duse Scan

skip functionallows

individualmemory

channeilock

out duringscanning

mode

FT -51R

21/4"W x 4%"H x 1 Ye"D

(2 Watt version shown.)

memories. A cloning feature duplicatesfavourite channels to another FT -51R.

A digital battery voltage display, fivepower output levels, the largest backlitdual band HT keypad made, Smart Mutertwo VFOs on both VHF and UHF as wellas available 2 Watt and 5 Watt versions,round out the exciting FT -51R. Plus, theoptional MH-29A2B Display Microphoneallows you to control volume and alsoaccess Memory, VFO, Call Channel, BandSelection and scanning functions. All ofthis in world's smallest dual band HT radio!

See the FT -51R with"windows" at your Yaesudealer today!

-I use the Spectrascope tofind new contacts faster"

"Yaesu did it again!"

Specifications Frequency Coverage

VHF RX 110-180 MHzTX 144-146 MHz

UHF RX 420-470 MHzTX 430-440 MHz

Spectrascope' Display Scrolling User Help Menu Alpha -Numeric 8 Character

Display Up/Down Volume/Squelch

Controls 8. Display Selectable Sub -Band TX Mute Automatic Tone Search (ATS) Digital Battery Voltage Display AM Aircraft Receive Scanning Light System (SLS) 120 Memory Channels

(80 w/Alpha-Numeric) Large Backlit Keypad 8. Display Automatic Repeater Shift (ARS) Multiple Scanning Modes 3 Selectable Scan Stop Modes

with Scan Skip User selectable lock function

w/15 combinations Automatic Power Off (APO) TX/RX Battery Savers Built-in Handy Cloning Feature 5 Selectable Power Output Levels Message system with CW ID Selectable RX Smart Mute" Cross -Band 8. One -Way

Repeat Functions DTMF Paging/Coded Squelch

Built-inAccessoriesConsult your local dealer

Peiliontunce without comptuntise.",YAESU UK LTD. Unit 2, Maple Grove Business Centre. Lawrence Rd., Hounslow. Middlesex. TW4 6DR

Specifications subject to change without notice. Specifications guaranteed only within amateur bandsSome accessories and/or options are standard in certain areas Check with your local Yaesu dealer for specific details

May 1995(ON SALE APRIL 13)VOL. 71 NO 5 ISSUE 1058NEXT ISSUE (JUNE)ON SALE MAY 11

EDITORIAL & ADVERTISEMENTOFFICESPractical WirelessArrowsmith CourtStation ApproachBroadstoneDorset BH18 8PWTr (01202) 659910(Out -of -hours service by answering machine)FAX (01202) 659950

Pays Internet address is:@pwpub.demon.co.uk You can sendmail to anyone at PW, just insert theirname at the beginning of the address,

e.g. [email protected]

EditorRoh Mannion G3XFDTechnical Projects Sub -EditorNG ("Tex") Swann GI TEXProduction/NewsDonna Vincent G7TZBEditorial AssistantZoe ShortlandArt EditorSteve HuntLayouts Richard Gale

Advertisement ManagerRoger Hall G4TNTPO Box 948London SW6 2DSTr 0171-731 6222Mobile (0585) 851385FAX 0171-384 1031

Advert Sales and Production(Broadstone Office)Lynn Smith (Sales),Ai lsa Turbett G7T1C (Production)

101202) 659920FAX (01202) 659950

CREDIT CARD ORDERSa co 1 202) 659930(Out -of -hours service by answering machine)FAX (01202) 659950

Front Cover Photograph: Craig Dyball

Cepplight PW PUBLISHING LTD 1995 Copyright to all drawings.photographs and articles published in Practical *Velem is fullyprotected and reproduction in whole or part is expressly forbidden. Allreasonable precautwns are taken by Practical AVOWS to ensure thatthe advice and data given to our readers are reliable We cannothowever guarantee it and we cannot accept legal responsibility for v.Prices are those current as we go to pressPoblislied on the second Thursday of each month by PW PublishingLtd_ Arrowsmith Court, Station Approach. Broadstone, Dorset 81118SPW Tel 1012021659910 Printed in England by Southernprint IWebOffset) Ltd Distributed by Seymour, Windsor House, 1270 London Road.Norbury. London SW16 SDK Tel 0181-6791899, FBI 01816798907.Telex 8812945 Sole Agents for Australia and New Zealand Gordonarid Gotch (Asia) Lta South Afnca Central News AgencySubscriptions INLAND f22, EUROPE f25. OVERSEAS I by ASP) f27.payable to PRACTICAL WIRELESS, Subscription Department PINPublishing Ltd , Arrowsmith Court. Station Approach, Broadstone,Dorset 8H188PW Ter 1012021659930 PRACTICAL WIRELESS is soldsubplot to the following conditions, namely that it shall not. withoutwritten consent of the publishers first having been given. be lent. re.sold, hired out Of otherwise disposed of by way of trade at more thanha recommended selling pnca shown on the cover. and that it shall notbe lent, re -sold, hired out or otherwise disposed of in a mutilatedcondition or in any unauthorised cover by way of Trade. ar affixed to oras part of any publication or advertising, literary or pictorial matterwhatsoever. Practical Wireless i5 Published monthly for S45 per year byPW Publishing Ltd . Arrowsmith Court. Station Approach. Broadstone.Dorset 8H18 8PW, UK Second Class postage paid at Middlesex. N J.Postmaster Send USA address changes to Practical Wireless. c/oPermit to post at Hackensackpending. The USPS (United StatesPoste' Service) number forPractical Wireless is: 007075 pw publishing ltd.

24

28

33

34

37

REVIEW - THE YAESUFT -51R TRANSCEIVERRichard NewtonGORSN inspects

the bands usingtheSpectrascopefeature onYaesu's smallestdual -band hand-held transceiver.

COMPUTING INRADIO SPECIALBITS & BYTES SPECIALTO launch the PW 'Computing in RadioSpecial' articles, Mike Richards G4WNCreviews a computer system designedespecially for amateur radio use.

CHOOSING & USINGYOUR COMPUTERThe Editorial team pass on a few tips tohelp you decide which computer Isbest suited to your radio shack.

BASIC COMPUTERLOGBOOKLooking for a logbook program to runon your IBM PC? Look no further, JohnBeaumont G3NGD has got one for you

AMATEUR RADIO &THE INTERNETMike Richards G4WNC takes a look thelatest computer attraction, TheInternet, from the amateur radioviewpoint.

POT RATIOS BYCOMPUTERJim Butler GM32MA shows you howyour computer can be used tocalculate potentiometer ratios.

L

40

42

46

48

50

53

56

60

65

AROUND THE LOOPRichard 0. Marris G2B20 looks at variationsof the loop antenna.

BUILD THE PW MARTLET70MHz FM TRANSCEIVERPART 3Mike Rowe G8JVE provides the p.c.bdesigns and associated component overlaysfor the project plus a description of thesynthesiser operation.

EXAMINING AN IMAGEPROBLEMMurray Ward G3K2B opens his RAE casebookagain to look further at Image interferenceproblems.

THE EDDYSTONE EC10RECEIVERBen Nock G4BXD says 'Its a classic', In hisdetailed look at the popular EC10transistorised receiver.

CRUISING ON THE AIRJohn Hines GOPNX tells how his radio skillswere put to the test on a cruise.

THE PRACTICAL WIRELESSDATACARD GUIDEKevin Nice G7TZC explains the purpose of theinvaluable PW repeater Datacards.

EQUIPMENTSCIFICATIONS - THEMYSTERIES EXPLAINEDIan Poole G3VWX delves into the mysteriousworld of receiver dynamic ranges.

ANTENNA WORKSHOPJohn Heys G3BDO shares his experience ofusing very low dipoles on 7 and 14MHz bands.

PACKET PANORAMARoger Cooke G3LDI reports on the'packeteers' he met on his recent trip toAustralia.

SUBS CLUBTake advantage of our Subscribers' Cluboffer this month and you'll soon becomputer friendly!

Other Regular Features COMING NEXT MONTHI Wireless gets busy on

76 Advert Index the fascinatingworld of Morse C

67 Arcade - All PW Servicesunder one roof

se keys and get orac

69 Bargain Basement DON'T MISS IT!7264

Book ServiceBroadcast Round -Up

0 ER YOUR COPY TODAY18 Club Spotlight9 Competition 68 Order Form9 Editor's Keylines 19 Radio Diary59 HF Bands 10 Receiving You12 News '95 54 Valve & Vintage16 Novice Natter 62 VHF Report

Practical Wireless, May 1995

HLI00E310 10M Linear. 10W in 100W out PEP

Suitable for 21.124/28MHz

HL1001320 20M Linear, IOW in 100W out PEP

HL1008:80 80M linear, 10W in 100W out PEP.

HL66V EM Linear. 10W in 50-60W out Rx Preamp

911660 6M Linear, 3/10W in Auto select 80/160W out

Preamp 299 C

9137VSX 2M Linear. 0.5 -SW in 20-35W out variable

gain preamp 109

HL62VSX 2M Linear. 5/10/25W in 50W out Preamp 235 C

HL36U 70cm Linear 6110W in 25/30W GaAs FET

Preamp ......... ........................ 155 8

HL63U 70cms Linear, 10/25W in 50W out GaAs FET

Preamp 259 C

911805 2M Linear, 3/1025W Up auto Stied 170W CAA

Rx Preamp.. . 389 C

P-SMC A.R.E. REG IWe believe in offering our customers the best deal possible, by dealing dia

Most of the following products we import direct. Consequently

MONTHS SPECIALSFT-890AT HF transceiver with Auto ATU

While stocks last

G400 & G400RC RotatorsG400 only £169 inc G400RC only £199 inc

Lower mast clamp GC038B £23 Rotators carr extra

AM.pTrollocHtsya-sPo.lepraOmusee cdaensiognnly;inddesbcuriiibde their

.010quality at its eery best"

£ Cart RUM 70cms Linear. 3:10+25WIT auto selec' 120W our

Rx Preamp..

210 C TRANSVERTORS210 C HUN 2M to HF 80,40.20.15.10M 2 5110W ()rive

210 C 30-40W op

169 C 110610 6M to HF Specs as above, ..

HX650

485 C

299 8

299 8

10M to 6M trartsverlor Non perfornance,

MGF1302 Preamp 0E1'12dB selectable 10.50W selectable

output input selectable, 100m V.' 1V RMS 369

REXON VHF/UHF HANDI'SRL102 VHF handi. 138-174MHz.

5 watt, complete with cell caseRL402 UHF handl, 410-470MHz.

5 watt, complete with cell case £199.00RNB1 1 1 7.2V 600mAh nicad for RL102 £21.50RNB112 12V 500mAh nicad for RL102 £39.95NC28/REXON Charger for RNB111 £18.00GMC 1 8/RE XON Charger for FN8112 £18.00RTN100 CTCSS unit £25.00RTS102 DTMF unit £19.95RCC101A Vinyl case RL102/402 RNB111 £9.00RBX100 AA cell case for RL102/402 £8.00

C88186 Univeral belt clip quick release £14 95

CARR A = £2.50

£189.00 B

REXONgOFFER

RL102 C/W NICAD &CHARGER ONLY

£189

RL -402 C/WNICAD &

CHARGER ONLY

£199

FT 8500 DUAL BAND MOBILEWe FT -8500 \ HF/ITIF dual band mobile transceiver hasbeen designed utilising new concepts to lead the nextgeneration of top -grade dual hand mobile transceivers. Allfunctions may he controlled fmm the new multi -purposeSmart Controller. The main unit provides a large, removablebacklit Omni -glow LCD which is used to show the specuvm of

the bands.

SPECIALINTRODUCTORY PRICE

Features: Conuvl front the new SI:1,11 ,111111 111111 ikrnuAr mountablewith 1 -SK 8500 112 memo!) channels Built-in CTCSSencoder Built-in DTMF message pager and DTMF codesquelch Generates CA. Morse code according to theincoming messages Switchable 9600/1200 baud PACKEToperation Frequency coverage: Rx 110-174/410-500

800h111z. 800-996MHz expandable.

Tx:144-146/430-440h1Hz.

C25.00

cushcrcrftOPPON /4 r o ro

Cmuosnhecyr.a t antennas are one of the best range currentlyavailable. They offer superb performance, innovativedesign, excellent build quality and outstanding value for

B CUSHCRAFT HF ANTENNAS05 14-18-21 -24-28MHz vertical, 3.2m long f279 D

R7 7-10-14-18-21 -24-28MHz vertical, 6.9m long £769 D

AV3 14-21-28MHz vertical, 4.2m long f85AV5 I.5-7-14-21-28MHz vertical, 7.4m long f149 C

AP8A 3.5-28MHz 8 band vertical L199 D

APR18A Radial kit for AP8A, AV3, AV5 f4940-2CD 40m 2 ele vagi 5.5dbd f439 D

204CD 4 ele 21hm beam 1439 DI S4CD 4 ele 15m beam £249 D

ADS 14-21 -28n1H2 3 ele vagi Wild L349 DMS 14-21-28MHz 4 demi 3 per band 1429 D

A3WS I 8-24MHz 3 ele vagi 8dbd L275 D

A103 10MHz extention kit for A3W5 1115 C

D4 7/14/21/28MHz rotary dipole 1229 D

1)3W 24.181 OMHz rotary dipl, £169 C

CUSHCRAFT VHF ANTENNASAR270 2rry70cm dualband vertical. 1.13m king £60 C

AR2706 2m(70cm dualband vertical. 2.3m long f89SRI 2m vertical. 1.2m long f35SRI, 6m vertical. 3.Im long f484148-105 2m, 10 He vagi, I3.2dbd L59

A144.201 2m, 10 ele crossed vagi. 12.2dbd f9911132 2m, 13 ele boomer, I 5.8dbd £99.95

1782 2m. 17 ele boomer, 18dbd f 169 ..........0A50.35 6m, 3 ele vagi. Mod £75.95.......04248 70cm, 24 ele boomer, 18.2dhd f115

L199 C

f185 C

.':'911 2m Oscar 22 ele ciw polarisation switch

70cm Oscar 38 ele cAv polarisation switch

All discounts are based on recommended retail prices.CARR B = £5 (Nandi's) CARR C = £9.50 (Mobiles) CARR D = £12.50 (Base Stations)

B

A

A

A

A

A

A

A

A

A

CARR E = ft 6.5 0

Head Office9-5pm Tel: (01703) 255111

Showroom/Mail Order9.30-5pm, 9-1pm SatTel: (01703) 251549

Service Dept 9-5 Mon -FriTel: (01703) 254247

SMC HQ SouthamptonS M House, School CloseChandlers Ford Ind EstateEcrstleigh, Hants S05 3BYTel: (01703) 251549/255111Fax: (01703) 263507HQ Monday - Friday

ARE Communications6 Royal ParadeHanger Lane, EalingLondon W5A lETTel. 0181-997 44769.30ar31 - 5.30pm Monday -Friday9.30crrn - 1.00pm Saturday

Reg Wa1 WesteWest St?AxminsDevon 1Tel (01;9 00am -

2 Practical Wireless, May 1995

47rTehteaiUleKr'sfoNroolli

ect with the manufacturer we are in effect "cutting out the middle man"., we are able to offer OWER PRICE than previously possible.ACM-COAXIAL SWITCHES SPEAKER MICS

SPECIFICATIONS MS102 for lcomCX401 S0239 Sockets £37.50

4 -way 0-500MHz 1kW CW & Yaesu

CX401/N 'N' Sockets £39.95 2.5kW PEP ONLY £19 .95

CX201 S0239 Sockets £18.50

CX201/N 'N' Sockets £19.95

(built in lightning protection)

2 way 0.1GHz 2.5W PEP0.5dB insertion loss.

ESTABLISHED1958

II MS107 Mini versionfor Rexon RL102/402

YAESU/ICOM

ONLY £12.95

NOW BAGloi IN STOCKPOKY TOKY WKX 12002M QRP transceiver 10m W crystalled

on 144.55MHz

Supernet receiver with 2 audio settings.

runs on 2 x PP3 batteries.

£29.95 inc

MANSON EP20 20A PSU3-15V DC adjustable 18A

continuously 20A max.

Built-in Volt and Ammeter

thermostatically controlled fan.

ONLY £79.95 inc

VHF/UHF Handi's and Portables 0 HF EQUIPMENT0ICOM IC-2GXE

IC-2GXET

ICW-21E

ICW-21ET

KENWOODTH-22 Our Price £210

TH-28 Our Price £259

TH-78

TH79E

TH-42

Our Price £399

Our Price £399

Our Price £239

YAESUFT -11R

FT -41R

FT -815

FT -51R

FT -290R2

FT -690R2

FT -790R2

Our Price £219 Save £30




Save £29

Save £40

Save £40

Save £50

Save £30








I C OM IC -737AIC -736

IC -738

IC -729

IC -728

IC -707

KENWOOD

Our Price £1379

Our Price £1649

Our Price £1399

Our Price £1175

Our Price £885

Our Price £785

TS-950SDX Our Price £3349

TS -850S Our Price £1529

TS-850SAT Our Price £1649


TS-450SAT Our Price £1379


TS-50S...Our Price £899TS -140S Our Price £799

YAESUFr -1000.

FT -990

FT -9900C

FT-890AT

FT900

FT900AT

FT840

Our Price £3299

Our Price £2019

Our Price £1759

Our Price £1149

Oue Price £1199

Our Price £1379

Our Price £799

0VHF/pHF Base & MobileSave £170 10 0 NI IC -820H Our Price £1489 Save £200

Save £200 IC -275H Our Price £1249 Save £140

Save £150 IC -281H Our Price £359 Save £40

Save £150 IC -2700H... Our Price £739 Save £90

Save

e £111100 IC -2340H Our Price £619 Save £70

KENWOODTS -790E

Save £450 TM -742E

Save £170 TM -732E

Save £200 TM -733E

Save £150 TM -702E

Save £170 TM -255E

S

Save £170 TM -455E

£100 TM -251E

Save £100

Save £400

Save £280

Save £240

Save £350

Save £150

Save £170

Save £100

YAESUFT -736R Our Price £1569 Save £220

FT -5200 Our Price £599 Save £80

F-5100 Our Price £559 Save £70

FT -2500M Our Price £329 Save £40

FT -2200 Our Price £329 Save £50

Our Price £1649

Our Price £749

Our Price £599

Our Price £659

Our Price £489

Our Price £799

Our Price £899

Our Price £349

Save £200

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Save £40

* Icom prices are subject to confirmation due to exchange rate variation

1 & CoI Paradeet

C13 5NY)7) 3491815pm Tues-Sat

SMC (Northern)Nowell Lcme Ind. EstateNowell LcmeLeedsTel. (0113) 235 06069.30crm - 5.00pm Monday -Friday9 00am - 1 OOpm Saturday

SMC (Midlands)102 High StreetNew WhittingtonChesterfieldTel. (01246) 4533409.30am - 5.30pm Tuesday - Saturday

SMC Bizmingham504 Alum Rock RoadAlum RockBirmingham B8 31 -TXTel. 0121-327 14979 00arn - 5.00pm Tuesday - Friday9.00crm - 4.00pm Saturday

Practical Wireless, May 1995 3

YOU WANT

AN NF -851.

YOU WANT

A HAM r.1

THIS

IS WHAT

YOU WANT.

Fica000!Iklt-,

This is it The SG -2000 HF-SSB. With 644 ITU

and ham frequencies -including SITOR telex

channels- permanently etched into memory.

Plus 100 user programmable frequencies and

easy Weather -fax connections. A real power-

house that produces a full 150 watts. The

SG -2000 HF-SSB. Moat or ashore, on the job

or on the road, this is what you want. Call us.

NO COMPROMISE

COMMUNICATIONS

The SGC Building P.O. Box 3526 Bellevue, WA 98009 USA(206) 746-6310 Fax: (206) 7466384

1-800-259-7331

SUMMER 1995CATALOGUE

test equipment

FEATURE PROJECT:

Multi FunctionEPROM Programmer

The Summer '95 edition has 280 pages packedwith over 4000 products and now with news and

features including a full construction project.

The computer section is greatly increased with newranges of equipment and accessories for PCs including:

Mother boards. CPUs and SIMMsCD ROM drives and hard drivesSound cards, I 0 cards, disc drivecards and video cardsMice, trackerballs and joysticksPower supplies and cases

Feature project for an EPROM programmer

W New 20MHz 'scope from Leader, training systems fromFlight and an extended range of mobile phone batteriesand accessories from Uniross

10- Latest addition from Velleman kits including a videodigitiser card

10. 280 pages, 26 sections, over 4000 products from someof the worlds finest manufactures and suppliers

Available at most large newsagents, from 13th April. ordirectly from Cirkit

Ilk Send for your copy today!

Park Lane Broxbourne Hertfordshire EN10 7NOTelephone: 01992 448899 Fax: 01992 471314ICirkit Aocess

=I=

Cirkit Distribution Ltd


THE THREE POINTS OF THE KENWOOD TRIANGLE REPRESENT ADVANCED TECHNOLOGY, QUALITY AND STYLE

040I Oft *it*

le 4111111 ftaft

ft

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fteft : ft ft: :' .010011111ft aa,

1, ft

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loft/loft . . .. ft :ft

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41

SO MANY FEATURES, IT NEEDS A MANUAL.SO WE BUILT ONE IN.

901 \ x\11,/ 0

0oA °°\",A/1,3°

Kenwood's TH-79E marks a new high in user-friendly handheld tranceivers. This slim -line FM dual -banderfeatures a dot matrix LCD menu, which helps you to access the many class -leading features of this stylish unit.

Features that include an FET power module for longer battery life, 82 memory channels with ID, DTSS and pagerfunctions, Automatic Band Change and DTMF memory function for auto -dial operation. Confused? You won't be.Just call up the menu. Or ring 0923 816444 for a full information pack.

KENWOODHOME AUDIO, CAR AUDIO, COMMUNICATIONS EQUIPMENT, TEST AND MEASURING INSTRUMENTS, TELECOMMUNICATIONS

'-IN TOUCH WITADI -from Taiwan AT -200 HandheldThis 2 metre handheldmanufacturers. We are

144-146MHz Tx5 Watts on 12V DC20 Memories1750Hz ToneCTCSS optionScanning/Call4x AA dry pack

We have thepower

The Manson is back! We've increased our ordersonce again for these superb power supplies butyou just keep on buying them! Sorry to keep somany of you waiting. If you don't yet know whatall the fuss is about check this out! The EP925 isa variable voltage PSU that gives a continuous25A current, peaking on 30A. Twin meters giveyou current and voltage readout and thethermostatically controlled fan keeps things cool.ideal for powering any of todays HFtransceivers. When you check out the price of amatching power supply for your rig. you'll seejust what great value it is at just £99.95.

If you don't need all that power then the EPXI5may be the one for you.

New!Half catalogue, half price list -why not ,gcryour copy of our new CataList! Just send u.%four first class stamps and we'll send youone by return. Crammed full of interestingnew products and some good old favourite.%as smell

INTERNET ADDRESS:[email protected]

i nfo@lowe. demon . co. uk

41::ster414-,.offa er

YAESU

is amazing value. ADI is made in Taiwan by one of the largest computerone of the selected dealers.

130-170MHz Rx3 Power levels6 Channel stepsDTMF built-in5-15V operationBattery saver

ONLY

£169.95BNOS VHF and UHF linears - for theserious Dxer What's the difference between a power amplifier and a linear?Try a BNOS and compare it with some of the other products that call themselves linear and you'll soon findout! If you are going to work that DX you need to be loud and clear and BNOS linears will give you both.Models available with or without pre -amps and all can be RF switched or hard switched depending on howyou like to work. Full specs available on request.CLP14410100 2m Linear with pre -amp; lOW drive; 100W output £255.00CLP1441050 2m Linear with pre -amp; 10W drive; 50W output £169.95CLP1443100 2m Linear with pre -amp; 3W drive; 100W output £289.00CLP144350 2m Linear with pre -amp; 3W drive; 50W output £289.00CLP43210100 70cm Linear with pre -amp; 10W drive; 100W output £439.00CLP4321050 70cm Linear with pre -amp; 10W drive; 50W output £255.00CLP432150 70cm Linear with pre -amp; 1W drive; 50W output £289.00CLP43225100 70cm Linear with pre -amp; 25W drive; 100W output £375.00CLP5010100 6m Linear with pre -amp; 10W drive; 100W output £289.00CLP501050 6m Linear with pre -amp: 10W drive; 50W output £169.95CLP50350 6m Linear with pre -amp; 3W drive; 50W output £169.95CLP7010100 4m Linear with pre -amp: 10W drive; 100W output £289.00CLX14410100 2m Linear; 10W drive; 100W output £219.00CLX1443100 2m Linear; 3W drive; 100W output £255.00CLX43210100 70cm Linear; 10W drive; 100W output £399.00CLX4321050 70cm Linear; 10W drive; 50W output £219.00CLX432150 70cm Linear; 1W drive; 50W output £255.00CLX43225100 70cm Linear; 25W drive; 100W output £345.00

If you'd like all the secrets of the top Dxers, we've agreat book written by the experts themselves. It'scalled the VHF UHF DX Book and contains chapterson propagation, antennas, transceivers, transverters.linears, pre -amps. accessories and most importantly.

the techniques you should use to get the most out ofVHF and UHF operating.Its bang up to date.

.01144 -men M4

OM ma. WW

Orr EnL

144 Mg/ 100 WATTUS1111 0101.11/1/M V

=1. Rd

BERKSHIRE

3 Weavers WalkNorthbrook Street

NewburyTel: (01635) 522122

Lowe Electronics have been appointed'Master Dealer' by YAESU UK

NORTH EASTMitford House

Newcastle Int. AirportNewcastle Upon TyneTel: (01661) 860418

LOWE

WALES & WEST79/8 1 Gloucester Rd

PatchwayBristol

Tel: 0117-931 5263

LovChesterfield Road,

H THE WtoRLIDGreat New Wire Antenna Systems FromChelcom's CAHFV1 h.f. vertical antenna (see last month's ad) has become the fastest selling h.f.vertical in the UK. with over 250 happy users. Hot on the heels of this wonderful antenna, Chelcomhave now produced a superb range of new wire aerial systems and components. Once again they'vechosen to use only the highest quality components. from specially designed balun cases and dipolecentres to the wonderful new FlexWeave' antenna wire. Just wait 'till you see FlexWeaveTM' - amulti standard wire so flexible you can tie knots in it and undo it time and time again. It is used in alltheir ready to hang antennas and also available on its own for those who like to roll their own!

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Chelcom Windoms - Ready To Hang!Two Windom antennas, one covering 80 to 10m and 133 feet long and a shorter version just 66 feet long covering 40 to 10m forthose with smaller gardens! Both made from the same high quality components including FlexWeave" antenna wire and a 4:1balun. Supplied ready to hang. Both antennas will let you loose with a whole 1000W p.e.p.!CA8OW for 80m is just £65.00 and the CA4OW for 40m is just £55.00.

Chelcom G5RV'sThese G5RV's really need to be seen to be appreciated. You really need to check out the quality compared to other cheapervarieties - there is no comparison! Again the components used are of the highest quality, specially designed for heavy duty useand built to last. For most people, erecting antennas is a major problem - better to do it just once! Chelcom offer the largestrange of G5RV's catering for most installation requirements.

CAG5RVH Quality half size G5RV using FlexWeave" and 300 Ohm slotted ribbon feeder. Supplied ready to hang at just£35.00.CAGSRVF Quality full size G5RV FlexWeaveTM and 300 Ohm slotted ribbon feeder. Supplied ready to hang at just £45.00.CAGSRVHP Quality half size G5RV with FlexWeave" balun and 450 twin feeder. Supplied ready to hang at just £65.00.CAG5RVFP Quality full size G5RV with FlexWeaveTM' balun and 450 twin feeder. Supplied ready to hang at just £75.00.

End -Fed Antenna. For those that like the simple life or don't like feeders hanging about, the Chelcom end -fed design offers asimple, unobtrusive solution. Just 66 feet long, the CA66EF will fit nicely into many smaller gardens and costs just £55.00,ready to hang.Chelcom MultiSystem Aerial Components For DIY Aerial Systems

CABALUN11 1 to 1 balun £30.00 CABALUN51 5 to I balun £30.00CABALUN41 4 to 1 balun £30.00 CADIPOLE Dipole centre £3.95CAINS Insulator (pair) £1.50 CAFLEX FlexWeave multistranded

antenna wire 20m pack ..£16.00PlusCAHFV1 HF vertical antenna

resonant on 80m £119.00

Lowe also stock a wide range of books covering all aspects of antenna design and construction. A full range can be seen in all ofour branches. We also stock a superb range of quality test equipment that anyone building antennas really needs to have.including Diamond power and s.w.r. metres, MFJ antenna. s.w.r. analysers and AEA analysers.Just send us four first class stamps for our complete Antenna Fact Pack which includes Chelcom's MultiSystem components andverticals, Hygain, Butternut, Vargarda and the full range of rotators from Hygain, Yaesu and Emotator.

SOUTH EASTCommunications Hse.

Chatham RoadSandling, MaidstoneTel: (01622) 692773

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Leeds

North YorkshireTel: 0113-245 2657

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ChestertonCambridge

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ve ElectronicsMatlock, Derbyshire DE4 5LE Tel: (01629) 580800 Fax: (01629) 580020

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The Hustler 6-BTV, groundmountedThe Hustler 6-BTV in my opinion

is very well made. it looks like itshould certainly stand up to a fewhigh winds when other aerialswouldn't (as I've found in the past,despite wind survivability claims!).I've used several commercialtrapped verticals over the years.and the 6-BTV worked just as well,if not better, than others. Whenground mounted, it gave good per-formance over unobstructed paths.

The supplied instructions wereextremely clear and concise, follow-ing these I had the aerial assem-bled in less than half an hour.

What did suprise mewas the relatively low price, for thequality of construction I found thisto be very reasonable indeed. Ifyou're in the market for a compactground -mounted HF multi -band ver-tical. I wouldn't hesitate in recom-mending the 6-BTV.

Chris Lorek G4HCL

John Goodall GOSKR roseto the challenge of reviewingthe Hustler HF MobileAntenna System by borrow-ing a Kenwood TS -SOStransceiver so he couldoperate from a test site inthe New Forest.

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Accurate tuning is made possible by the wide range of tuningflexibility designed into our verticals. Not only can you use thenormal adjustable tubing to change resonance, but the trapsthemselves can be field tuned for an additional 2 MHz. shift.This flexibility will enable you to acheive a good S.W.R. evenif your installation is not ideal.

All Hustler verticals will easily handle the full legal limit ofpower and will cover 10/40 meters with a S.W.R. of 1.6:1 atband edges. 75 or 80 metre band width on the 5BTV and 6BTVis 80 Khz. under 2 to 1.

We believe that a fixed station antenna is only as good as itsability to stay up. We further believe that the mechanical designof our verticals is superior to any. Large diameter 11/4 inch tub-ing is used from top to bottom. Our base assembly utilizes acentre tube. With a .315 inch wall thickness. unequaled in theindustry. The trap coils are wound around solid one inch diame-ter fibreglass cores. Our rugged construction is so obvious thatwe invite you to look at our verticals and compare them toother brands. One glance will convince you.

Solid signals, solid construction and solid value -three solid reasons to purchase a Hustler vertical. from coastal.

Before long. I had the RM-20S resonanton 14.160MHz, with the s.w.r. readingjust above 1.1:1. This was with 360mmof tip protruding from the adjuster.At 14.058MHz, the FISTS frequency. I

found the s.w.r. was acceptable at 1.6:1.The dial reached on 2:1. This proved aneven greater bandwith than that pub-lished by the manufacturers.I worked RA3REM and RK3VWF, bothwith reports at 5 and 6: YU70GW and9A1CAH 5 at 9. all on 50W.I found that using the Hustler HF MobileAntenna System was indeed a plea-sure.) think that the cost of the 'StandardResonators', which I feel are adequatefor this country, is quite reasonable forthe excellent quality of the equipment.Picture and Quote from JohnGoodhall review in Practical Wireless

4BTV HF Base 10.15-20-40 meters £142.955BTV HF Base 10-15-20-40-80 meters £160.956BTV HF Base 10-15-20.30-40-80 meters £179.95RM-10 10m Mobile Resonator 150-250Khz bandwidth 400W £17.49RM-15 15 Mobile resonator 100-150Khz bandwidth 400W £18.49RM-20 30m Mobile resonator 80-100Khz bandwidth 400W £26.49RM-30 30m Mobile resonator 50-60Khz bandwidth 400W £26.99RM-40 40m Mobile resonator 40-50Khz bandwidth 400W £27 49RM-80m Mobile resonator 25-30Khz bandwidth 400W £28.49RM-10S 10m Mobile resonator 250-400Khz bandwidth 1 5KW £24.95RM-15S 15m Mobile resonator 150-200Khz bandwidth 1.5KW £26.95RM-20S 20m Mobile resonator 100-150Khz bandwidth 1.5KW £29.95RM-40S 40m Mobile resonator 50-80Khz bandwidth 1,5KW £34.95RM-805 80m Mobile resonator 50-60Khz bandwidth 1.5KW £45.95MO -1 Mobile mast 54 inches long tilts at 15 inches £27.95MO -2 Mobile mast 54 inches long tilts at 27 inches £27.95MO -3 Mobile mast 54 inches long, solid rubbercoated £22.95MO -4 Mobile mast 22 inches long, solid rubbercoatedi All masts end in a 3/8 thread, for mounting. Ideal for any strong CB style mount and cable.)

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"The best antenna there is for HF!"I have tested the Huster HF Mobile with the rated power andhave measured the O factor and it is the nearest to 300 inany antenna I have seen! I have also fed it with inductiveand capacitor matching including both to obtain 50 ohmsinput on 40/80 mtr and and have a band width of between50 and 75 kcs compared with other mobiles which had only10 to 15kc band width. The best antenna there is for HF!Since using the Hustler I have contacted stations in "IndiaVU2TTC". "Sri Lanka 457RO". "Trinidad 9Y4TD", Africa9X5GC'. "KAI V/TS. 3DAA0BM, Australia VK7OH. Barbados3P9EM and the Falklands VP8CGH with signal reports rang-ing between 5/5 to 5/9. as for 9Y4TO who was surprisedwhen I told him I was mobile due to my signal strength. Astation in Johannesburg called me "ZS8BEW" as he thoughtI was in one of the Johannesburg suburbs. this was when Iwas in contact with KC9B1 we then had a three way con-tact, not bad from a car don't you thinkAs for the antenna. I have tried inductive coupling andcapacity matching as per ARRL handbook mobile sectionand this was not needed.The resonators are very well constructed as so the mostwhich can be used as a 1/4 wave on 6mtr, the band width isas advertised for each band. "as the instructions state 2.1swr or better", I obtain 1.5 to 1 and less on 10, 15. 20 mHzbut what did supnse me was the band width on 80 mtr aswith other antennas. I could only move frequency of about10 kcs either but with this resonator I can move 30 kcseither side of the tuned frequency. Now when i go campingall I take is the required camping equipment and the Hustlerantenna which I use with a TM -band adaptor. so I can oper-ate any three frequencies without having to change res-onators. The mast is hinged so it can be folded to fit thetrunk and apart from that I also use the quick disconnectattachment which I also obtained from CoastalCommunications.To end this letter which sounds like an advert, all I wil say topast, present or future mobile operators is, try this antennaand I can tell you that they will not be disappointed with theresults and also excellent service from CoastalCommunications.

73 David Hudson, G4WOE E. Sussex

COASTALCOMMUNICATIONS

19 Cambridge Road,Clacton -on -Sea, Essex C015 3QJ

01255 474292

Short wave listeners are usually very dedicatedradio enthusiasts. And in fact, if we're honest,most of us (and I include myself) spend more timelistening on the bands than we actually spendtransmitting.

Quite honestly. I've felt that listeners havebeen neglected in PW for a long time...but that'sgoing to change. and we need your help! Anyonecan be a s.w.l. (including transmitting amateurs ofcourse) and I think there's a job waiting for keens.w.l.s who read PW.

So. are you a keen s.w.l. who listens on theamateur bands? Do you listen regularly for s.s.b.or c.w.? If so. you'll be able to help PW with anew initiative which we're planning to launch inthe summer.

With the new idea, I'm hoping that the manyfrustrated hours on the bands won't be wasted infuture. You'll be able to help other PW readers if

)(iu're able to spare some time to listen, and towrite in to the magazine.

Anyone will be able to join in the new ven-ture, and the Editorial team would particularlylike to hear from our readers abroad. If you are(for example) living in Europe. North or SouthAmerica. Australia or New Zealand...we could dowith your help!

The new idea will work in reverse too, andI'm hoping that readers in the UK, Eire and 'nearEurope' will be able to help readers who are onthe air from DX locations. So, if you can sparesome time to listen on the bands, are prepared towrite in to the magazine...we'd like to hear fromyou as soon as possible.

Address your letters to me at the Editorialoffices in Broadstone and I'll provide full detailsby return of post. By working together we'll beable to get even more out of our hobby!

Planning PermissionNI> he2. I'm:. in tltc Januaty tour ol Lertain-ly generated a lot of feedback from readers. Infact. I've been showered with letters from peoplewho've had some rather unfortunate dealings withthe planning authorities.

The only thing which now seems certain aboutplanning permission (in regards to amateur radioantennas, towers and masts) in the UK, is thatthere's a great deal of confusion! And to makematters worse, it also seems from the letters I'veseen, that planning applications often turn into

personality clashes and squabbles!So. unless you're a member of the RSGB

(they've got a comprehensive planning permis-sion support system for their members) what doyou do when it comes to planning permission?Apart from joining the National Society and sav-ing yourself a great deal of trouble and possiblelegal fees (from what I've read in some of the sadstories in letters received, the RSGB membershipfee could save you money and trouble in the longrun!) what can you do to help yourself?

To help. I'm hoping to get a planning permis-sion guidelines statement on towers/masts andantennas for radio amateurs from CentralGovernment. I also hope we can get a centralbody representing local and district councils tocomment.

In the meantime. I would be most interested tohear more from you on your planning problems.In particular (as this appears to be the main prob-lem in the letters I've read) where it seems thatit's one individual causing difficulties and theplanning application has become a personalityclash.

To round off this month. I'd like to invite anyof our readers based in Eire, or in mainlandEurope to pass on their comments. How does theplanning permission system work in your coun-try? Perhaps you can help us to help ourselves!

Poo Aorioe0X1-0

COIFPETITION CORNERG WEDS P EQL U B I AURRW X N R R S K A T P NCT ZO E GQOMGS R OT R E AOYS WY V Y F F I E Y AZ Z K

G C F OP P MNNS 1ST T R T

H N P P POINTSE ES YESZS I I L HA ABNS1 L T Y

B X X ATE O L AI K R T T HSIHSF ANWL D F R AQUKK Q RYBK F YBR A W.1 DLQTV A HOE E WMI L WGCQI Y D K K OUP L P V AP AKXZ X MR F BL OUDMC VCS Y I LXS I Ul I I DGOVAY T YE MHNDANUZ WF

Wordsearch rules:Twelve different words have been hidden in the letter grid. Theyhave been printed across (forwards or backwards), up and down,diagonally, but they are always in a straight line without odd lettersbetween. You can use the letters in the grid more than once for dif-ferent words. Once you have found all 12 words, mark them on thegrid and send it, along with your name and address (photocopiesaccepted with the corner flash) to our editorial address, marked'Competition Corner' Wordsearch May 1995.

Words To Find

MartletLowPower

CrystalAntennaQRPFocalPoint

MilliwattsOperatingBooksKeylines

Name

Address

Send your entry (photocopies acceptable with corner flash) to:Competition Corner, Wordsearch Competition, May 1995, PWPublishing Ltd., Arrowsmith Court, Station Approach,Broadstone, Dorset BH18 8PW. Editor's decision on the winneris final and no correspondence will be entered into.

FIRST PRIZE: A year's subscription to Practical Wireless or a£20 book voucher.SECOND PRIZE: A six month subscription to Practical Wirelessor a £10 book voucher.

-1 SUBSCRIPTION -I VOUCHER

Entries to reach us by Friday 26 May 1995.


111111111111111111111111111111111111111111111

Please send your letters to theEditorial offices in Broadstone.Reader's letters intended forpublication in 'Receiving You'must be original and not beduplicated. Letters are accepted on the under-standing that they have only been submitted toPractical Wireless. Please ensure that your letteris clearly marked 'for publication in ReceivingYou' and that it has not been submitted to othermagazines. We reserve the right to edit or short-en any letter. The views expressed in letters arenot necessarily those of Practical Wireless.

ER CIFIVING TheStraerceLievtewill

£10voucher worthto spend on itemsfrom our Book or

other services offeredby Practical Wireless.

All other letterswill receive a £5

voucher.

Planning ProblemsDear SirWith reference to the two interesting letters aboutplanning problems in the March issue. I have beentrying for the last 15 years to get a 45ft tower at thebottom of my garden. My last planning applicationwas for a tower 33ft up, 13ft down, behind trees thatare 22ft high, and would be some 170ft away fromthe rear elevation of my house.

This has all been to no avail, if only someonefrom planning will come and see me and tell mewhat I can do, not keep writing and telling me what Icannot do. Early on in this charade, I asked this ques-tion, only to be told, 'it doesn't matter what aerialyou want to put up, we are going to stop you'. Imade the planning officer repeat this at a publicappeal.

This same planning officer three weeks beforemy first application, gave permission for a 3 -elementtribander on top of a four storey block of flats on avery high point close to this location, just at the topof my road that can be seen for miles around. Thiswas done without an official planning application,but was just confirmed by letter 'that all was OK'.This the council deny, but I have two copies of lettersshowing this fact dated 1982 and 1984.

About three years ago they put a link road fromour new Brighton Bypass and a Sainsbury's super-store at the bottom of my garden, about 200ft away.This was the local golf course. I do not live in a con-servation area, so my problems are not due to this,and my paperwork is now five inches high!

I did win one appeal, but this was over -turned bythe Secretary of State a few days later. So, the RSGBand myself took it to the high court for being deniednatural justice. We won the court action with thecouncil and the DOE requesting an appeal, but thejudge said, "No, I do not consider that you gave thisman a fair crack of the whip". I then put in a plan-ning application for the mobile mast and the councilturned it down again.

It is my opinion that Hove Borough Council arebeing vindictive, malicious and unnecessary. At themoment they are in the process of serving anenforcement notice on me to take down the 20ft polebehind 22ft trees. As I am heavily involved inRAYNET, I do not know how I am supposed to workin an emergency and they do not seem concerned asagain I cannot get them to see me after requests byletters.

Maybe through your magazine we can deter-mine what is a maximum mast height before wehave to apply for planning permission, let's say 30ft.If we can produce a letter that you and the RSGB canput together, a copy of which can be published inyour magazine, signed by any interested parties andsent to our MPs. This will perhaps bring pressure tobear.

Doing it this way makes it easier for all amateursto get involved. Perhaps if we show our numbers,then 'they' may at last listen to a louder voice. Theprotest needs to be done in such a way that every-one will get involved just because they are radioamateurs.D. Browne G4XKFEast Sussex

STAR LETTER It * *

Wonderful SurpriseDear SirI am writing to say thank you to Practical Wireless for the wonderful surpriseI received on my return from Cyprus last week. It was my prize in the shapeof the Yeovil 3.5/14MHz Transceiver, which I won in the November 1994 PWCompetition.

Last year my prize for winning a competition was a year's subscriptionto Practical Wireless. I have not put pen to paper to 'Receiving You' before,but am writing now to say thankyou for an interesting magazine. Thanks forthe regular features, and the help given to readers like me who have tried topass the RAE, failed and tried again, failing once more. I then gave up, until I

read the reprint of Practical Wireless, the Passport To Amateur Radio.To any reader I would say, finding it hard, get the reprint and get your B

licence! At 67 years old, I'm trying my Morse to get my A licence and put myYeovil transceiver prize to good use.

Thanks again for the prize and thankyou for a good amateur radio maga-zine.V. G. Saundercock G7PHJCornwall

More Planning ProblemsDear SirAs a Local Authorityplanning administrator, Iwas rather concernedover what I considermisleading advice givenby Arthur BagleyGW4EKE in his letterwhich was published inthe March issue. Thisrelates to the suggestionthat an amateur wishingto apply for planningpermission for a mastshould give the LocalPlanning Authority theminimum ofinformation, other thana location plan, with nodetails of the antennalikely to be affixed.

If Mr Bagley wasgranted permission inthe past after supplyingsuch scant information, Ifeel it was either a longtime ago, or he was verylucky. Planning officersand/or a planningcommittee, whendetermining such anapplication for anamateur mast and

antenna will need toestablish whether thevisual amenity of theneighbourhood is likelyto be detrimentallyaffected by the proposal.

A number of factors,such as the antenna'sheight, its size andlocation are crucial inthis process, and noprofessional planningofficer or committeemember worth his/hersalt will attempt to makea judgement without allthe relevant data. If theapplicant has notsupplied this data, theLocal Planning Authoritywill request furtherinformation it needs.

Should this essentialinformation be withheld,the application willalmost certainly berefused. With the fee forsubmitting a planningapplication currentlycosting £80, there seemslittle point in getting arefusal through failureto give the planners

adequate information.My advice therefore,

is to give as muchinformation about themast and the affixedantenna. Certainly, ifpermission is grantedfor the mast alone, theerection of a largeantenna system on topwould be considered amaterial change in thedevelopment and wouldrequire a furtherplanning permission. Ifthis second permissionis refused, the mast isnext to useless, so, bestto supply all theinformation in one go.

Agreed, if anapplication is refused,there is a right of appealto the Secretary of Statefor the Environment, butnational statistics showthe success rate to bearound 30%. In anyevent, a planning appealshould not be attemptedwithout professionalhelp.

Incidentally, failure

1111M111111111=11s


Vowed To Return

Illegal Use Of Amateur BandsDear SirI'm writing about the possible unauthorised use of 144MHz and further illegal air-borne use of the amateur bands.

While reading Skywings, the journal for hang glider/paraglider enthusiasts, Icame across an advertisement involving amateur radio equipment. It is not theonly advert I have seen in the same January 1995 copy. The other advertisement(which I have sent to the RSGB for action), openly advertises 144MHz transceiversfor aviation communication. I hope that this will come to the notice of the regulat-ing authorities.John Wood G3EAY, Essex

Morse CodeDear SirI was very interested inthe star letter whichappeared in the Marchissue of PracticalWireless. Because I toohave had a very similarexperience as JoeJohnson in learning theMorse code and passingthe test.

For over two years Ihave been religiouslypractising and found itvery hard going attimes. I too had tapesand listened to MorseQS0s a lot when theformat was changed as Irealised there weresome parts of the Morsecode that wasn't tooeasy to copy.

I did have someassistance for a shortperiod from a localamateur, butunfortunately, it wasn't

possible to carry it on.However, I decided tohave a go when I visitedLincoln Hamfest lastSeptember as I thought Imight pass. But myresult was poor, failingbadly in both receivingand sending.

However, it gave mesome idea of what toexpect and decided nexttime I'd be moreefficient. It was after myfirst attempt thatanother local amateuroffered to give metuition three times aweek, and it is all thanksto him that I wassuccessful the secondtime I sat the Morseexam.

His name isMichael GOSMG. I amextremely grateful tohim for perseveringwhen at times I haddoubts myself as towhether or not I'd pass. I

am a little older thanJoe, being 77 and I dosuffer from very badmemory, plus I'm ratherdeaf. Hence the longtime it took me tomaster the Morse code,because I've had toreally imprint it in mythick skull!

However, I don'texpect you to print thisletter. But I would bepleased if you can use it,to encourage otheramateurs of my age andphysical disability not togive up and bedetermined to masterthe Morse code.

I'm not perfect by along chalk, but I've gotover the main hurdle, bypassing the test. I hopeto get a callsign of myinitials GOWMS as I shallbe very proud of myachievement.Maurice WilliamsG1NVB

to apply for planningpermission, where it isneeded, can result in theLocal Planning Authoritytaking enforcementaction. And the powersavailable to the Authorityin this area are quite far-reaching. At worst, theoffending structure willhave to be taken down,and there might be a fineimposed as well. Withthe cost of the antennahardware these days, itsjust not worth taking therisk.

The RSGB's bookletPlanningPermission...Advice ToMembers is well worthreading before applyingfor planning permission.Although afterthoroughly digesting it,the reader may feel soshell shocked as todecide to give up radioand take up growingroses instead! The staffat Council PlanningOffices, however, will bepleased to give you all

the advice you need andI would ferventlyrecommend this adviceis sought beforesubmitting anapplication.

Finally, there havebeen some rumoursfloating around recentlythat the planningregulations relating toamateur antennas andmasts might be relaxedin the near future.However, it must bepointed out that with theproliferation ofcommercial antennasrecently for the variousmobile 'phone networks,Local PlanningAuthorities are becomingincreasingly concernedover the adverse effectthese are having on ourvisual environment, somuch so that the LocalPlanning AuthorityAssociations arelobbying Government tomake the regulationsaffecting suchcommercial antennas far

more stringent. Thereseems little hopetherefore for the humbleradio amateur!Michael Bone G3VOODorset

Editor's comment:After reading the(many!) lettersreceived on thissubject following the'Keylines' comment,I'm inclined to agreewith Michael G3VOO.However, although I'mnot going to give upand grow roses - I'llknow in future thatthe only thing that wecan be sure of withthe planningpermission 'mess' isthat there's no singlestandard approach inthe process. It seemsto me that confusionand perhaps someprejudice towardsamateur radio mayrule in some CouncilChambers!

Dear SirA few years ago I lost my job through redundan-cy. This followed by a planned house swap, putan enormous strain on the bank balance. I foundmyself having to sell gear, in order to raise someready cash.

To see my beloved transceivers and associat-ed gear disappearing down the road was a terri-ble wrench. I vowed there and then, to return tothe air waves one day

Eventually, I got another job on a much lowersalary, only to be made redundant again, twoyears later. This imposed further strain on myresources. Now, three years on and I am stillQRT.

If this sounds like a sob story, I apologise. It'snot intended to be one, because the experiencebrought with it some enlightenment. You see,what I was trying to do was replace my 'BlackBoxes'.

But all the time what I really was looking forwas a return to the sense of achievement, andimmense pleasure, which I first experienced in1958 when I put my first home-brew station onthe air. It was a wonderful feeling and one whichall the commercial gear I have owned since hasfailed to duplicate. With this in mind, I have cometo the conclusion that the way forward for me isvia QRP and home-brew. It's cheap, puts thesense of achievement back and is well suited tomy favourite mode of c.w.

Over the next few months I hope to begin abuilding programme, and hope to be back on theair during 1995. I shall look forward to QRPingand I am sure that for me, it's the way back andwill restore the challenge and fun of amateurradio.Peter Nicholson G3MYZEast Yorkshire

Editor's reply: Welcome back Peter! I hopeyou'll provide an up -date on your progressonce you're back on the air.

Virtues Of QRP

Dear SirI know you welcome letters, views and opinions fromthe entire spectrum of radio amateurs, so I thought Iwould drop you a line extolling the virtues of QRP.As a recently licensed amateur, my choice of equip-ment and antenna were restricted by budget andspace.

I obtained a Yaesu FT -7 (10W p.e.p.) and a halfsize G5RV antenna, much to the friendly derision ofcertain compatriots! I have not got enough space toextend the half size G5RV in a straight line, so it isstrung in a 'V' formation from a tree to the house at aheight of 5m up with its ends 4m apart. Hardly idealyou would think!

I have just finished an s.s.b. QS° on 21MHz withVE3VHB in Ontario 14 400 miles away) who gave me5/3 report. I answered his CO call, but as is oftenadvised, added QRP after my call. He came straightback telling me that I was the quietest station thathad answered his call. The QRP had obviously inter-ested him.

I know my experiences are far from unique andthat greater things are done with less power, howev-er, the thrill of crossing the pond on s.s.b. with lowpower, when the other station may be using 1kW hasto be experienced to be appreciated!

Thank you for a first class publication. I particu-larly enjoy QRP constructional articles and intend tobuild the simple one valve transmitter for 3.5MHzwhich you recently published.John Constance GOVGDKent


Jackson's DialThe Norfolk basedcompany Isoplethics,who have recentlybegun a distributorservice for JacksonBros variable capaci-tors, drive compo-nents and relatedhardware, have announced the renewed avail-ability of the 6/36 slow motion drive and dialassembly (Cat No: 4103/A). The drive and dialassembly, measuring 123 x 95mm, comprisesa dual ratio 6:1 and 36:1 ball drive, black plas-tics coated escutcheon printed card scale, hair-line pointer and clear plastics window.

At a cost of only £19.50 including VAT &P&P (UK and EEC), the Jackson Bros dial anddrive assembly is described as being ideal forhome-brew projects, such as direct conversionreceivers, grid dip oscillators and wavemeters.For more information on the drive and dialassembly contact Isoplethics, 13 GreenwayClose, North VValsham, Norfolk NR28ODE. Tel: (01692) 403230

Prize DrawThe lucky winner of

the £50 Prize Draw asfeatured in the BookService pages of theMarch issue of PW

was Mr S. V.Jeffrey of New

Jersey, USA.Don't forget that

the names of all cus-tomers who order

books from this issuewill be entered into

the £50 Prize Draw for

S

Take Five From LynchAt the 1995 London Amateur Radio &Computer Show Martin Lynch G4HKSlaunched his unique, five year fully transfer-able equipment warranty. Martin's five yearwarranty covers all repair, replacement parts,servicing labour, collection and redeliverycosts on all new equipment brought from the'Lynch Mob'.

The G4HKS five year warranty, which isavailable for a nominal sum, is unique in thatit is fully transferable. This means that thepiece of equipment it covers can be sold orexchanged any number of times within the five years without losing thewarranty cover.

Martin says "Total confidence and absolute piece of mind for everyoneof my customers is what I intend. Yes, the modern designs are very reliablebut the same technology can and does occasionally fail and when it does, itcan mean a considerable bill for imported parts and for several hours ofhighly skilled labour".

Brian Greenaway G3THQ, Martin's Customer Service Manager adds"The new five year warranty is sure to set a 'benchmark' for user protectionin the UK and will also give the operator the chance to upgrade their gearevery five years and say goodbye to those repair bills forever!"

In addition to the new five year warranty scheme there is also a pro-gramme available to allow up to 15 months warranty on used equipment,up to eight years old. For more details you are invited to contact MartinLynch direct on 0181-566 1120 or leave a message on the LynchlineBBS on 0181-566 0000.

THE allAPTIIIM LYS11055 YEAR WARRANTY

visit Jaycee In JulyIn recent issues of PW, on the Dealer Panel pagethe Jaycee Electronics Ltd. advert has stated thatthey are closed for holidays from July 16 to August2. This was actually an error and is not the case.The PW team would like to apologise to JayceeElectronics and their customers for any inconve-nience or confusion caused by the error.

So, if you'd like to visit Jaycee in July or indeedat any other time why not go along to 20Woodside Way, Glenrothes, Fife KY7 5DF andhave a look at their range of new and second-handequipment. Alternatively give them a call on(01592) 756962.

Send in yournews,

photographs andproduct

information toDonna VincentG7TZB at the

editorial officesin Broadstone.

Short Wave League RallyingThe International Short Wave League (ISWL) haveinformed the 'Newsdesk' that they will be attendingthe following rallies during 1995:

Date Venue

28/05/95 Plymouth Amateur Radio Rally11/06/95 Elvaston Castle Mobile Radio Rally,

Derby25/06/95 Longleat Amateur Radio Rally, Longleat08/07/95 Cornish Amateur Radio Rally19/08/95 Staffordshire Hamfest20/08/95 Staffordshire Hamfest03/09/95 T.A.R.R.G. Telford

Members of the ISWL will be on hand at the rallystands to answer questions and to enrol new mem-bers. All the ISWL guides and publications will alsobe available.

There has recently been a change to the ISWLAwards Manager. To obtain details or to apply forany of the ISWL Awards you should now contact MrHerbert Yeldham G6XOU/G-20006, ISWLAwards and Contests Manager, Belle Fleurs,Wade Reach, Walton -on -the Naze, Essex C0148RG

Nevada NewsThis year's LondonAmateur Radio &Computer Show sawNevadaCommunications launcha range of new productsunder the DRAE banner.Included in the rangewere three 'classic'power supplies and amagnetic loop antenna.

The new DRAEpower supplies areBritish made. Nevadahave told us that thethree power supplies arebuilt to the high-est specificationand include pro-tection for over -voltage, over -cur-rent, short circuitand over -tempera-ture. The powersupplies are avail-able for 24, 12 and4 amps and arepriced at £139.95,£109.95 and £29.95respectively.

The new magneticloop marketed under theDRAE name reportedlyattracted a lot of atten-tion at the LondonShow. The loop usessemi -rigid 13mm coaxialcable for the radiatingelement, making it flexi-ble and therefore idealfor loft mounting or foruse as a low profileantenna.

There are currentlytwo versions of theDRAE loop available, the

ML80 and ML170. TheML80 covers the 7 -30MHz band, is just80mm in diameter,1.12m high and comescomplete with remotecontrol tuning. The retailprice for the ML80 is£179.95.

The ML170 providescontinuous coveragefrom 3 to 10.3MHz, mea-sures 1.7m in diameterand is mounted on a1.5in diameter fibreglasspole. The ML170 costs

£199.95 and as with theML80 is available with-out the tune control boxshould you wish toextend the antenna sys-tem for full frequencycoverage.

For more informa-tion on the DRAE rangeof products currentlystocked by Nevada youcan contact them at189 London Road,North End,Portsmouth, HantsP02 9AE.Tel: (01705) 662145,FAX: (01705) 690626


Thank You Ma'am - de G3AAJFebruary 14 was the day when AMSAT UK's well known joker, RonBroadbent G3AAJ, had to be on his best behaviour! He was to be present-ed his MBE from The Queen. The day was clear and bright as some 25 peo-ple stood outside Buckingham palace gates to congratulate Ron and Beryl(his better half) as they floated out of the Palace entrance.

Later at a reception attended by more than 40 family and friends fromAMSAT, the RSGB and amateur radio, Ron gave a light hearted account ofthe occasion. His next appointment may be at Newgate jail!

In his speech at the reception, Ron said the award was for AmateurRadio in generaland that he wasonly the holder.However, on behalfof amateurradioPWwould liketo say congratula-tions Ron. See youin 12 months forthe next 'gong' up?

Beryl and Ron Broadbent cutting the cake to celebrate receivinghis MBE, at the reception afterwards attended by more that 40family and friends.

Switches, Microphones And Power Supplies

South MidlandsCommunications (SMC)have recently informedthe 'Newsdesk' of somenew products, which arecurrently available fromtheir retail outletsthroughout the UK.

First on the 'new' listare series of two andfour-way coaxialswitches. The two-wayswitches comprise ofthe CX201 and CX201Neach with amanufacturer'sspecification of d.c. to1GHz frequencycoverage, 2.5kW p.e.p.rating and an insertionloss of 0.5dB.

The CX201 hasstandard S0239 socketswhereas the CX201Nfeatures 'N' typesockets. Retail prices are£18.50 and £19.95respectively.

The CX401 andCX401N are the four-way versions with a

manufacturer'sspecification of0-500MHz,2.5kW p.e.p.rating and 1kWc.w. The CX401has the S0239sockets withbuilt-in lightningprotection andcosts £37.50.The CX401N has'N' type socketsand is availablefor £39.95 (allprices includeVAT).

Secondly there aretwo new speakermicrophones availablein the shape of theMS107 and the MS102.The MS107 is a minispeaker microphonewhich matches theRexon RL102/402, issuitable for use withYeasu and Icomtransceivers and costsjust £12.95. The MS102is very similar in appear-

ance tothe YaesuMH12A2Band retailsfor £19.95.

Thefinal newproductfrom SMCis the EP -

1=1111111119

920 power supply unitwhich offers amaximum currentoutput of 20A and hasan adjustable output of3 - 15V d.c. It alsofeatures a built-inammeter and voltmeter,a thermostaticallycontrolled cooling fanand measures 150 x 145x 300mm. The price ofthe EP -20 is £79.95.

For moreinformation on any ofthe products mentionedhere contact SouthMidlandsCommunications,S. M. House, SchoolClose, Chandlers FordIndustrial Estate,Eastleigh, Hants 5053BY. Tel: (01703)251549/255111.

Alinco AdditionsWaters & StantonElectronics, in additionto their normal standat the LondonAmateur Radio &Computer Show, hada stand devotedentirely to the Alincorange of radio prod-ucts.

Alinco haverecently added a new144MHz f.m. transceiv-er to their range in theshape of the DR -150E.The DR -150E is a 50Wtransceiver featuring a7 -channel panoramicdisplay to allow theoperator to monitoradjacent frequencies.There is also extendedreceive coverage ofthe 430MHz band anda separate connectionfor packet radio withits built-in interfacewhich offers 1200 and9600bps.

With a retail priceof £349, the DR -150E isdescribed as alow costmobiletransceiveroffering one ofthe most com-prehensivepackage severpresented tothe radio ama-teur.

Also onshow was thefirst sample ofthe new AlincoDX -70 50MHzh.f. mobiletransceiver.The DX -70 is

claimed by the manu-facturers to be thesmallest all -band ama-teur radio h.f.transceiver, eventhough it's only a fewmillimetres smallerthan the Kenwood TS -50.

The Alinco DX -70features a detachablefront panel, coversu.s.b., I.s.b., c.w., f.m.and a.m. modes. Italso offers widereceive coverage from150kHz to 30MHz plus50 - 54MHz.

The price for theDX -70 has not yetbeen fixed and Waters& Stanton tell us thatthey expect the firstshipment sometime inMay. So, watch thisspace for moredetails!

BEI

New from Alincoox -n Hrt60, mobac/Wadable Iron, May

. .

ti

Jeff Stanton GSXYU pictured with theDX -70 in front of the stand devoted

entirely to the Alinco range of products atthe recent London Amateur Radio &

Computer Show.

Independent Group

The QL Independent User Group or QUANTA are

currently the largest computer club in Europe

with an internationalmembership. The group has

been running for 11 years, is run by amateurs and

is solely for amateurs with no commercial spin

off.Members of QUANTA receive a monthly

newsletter and have access to a free library of 70

disks. There are workshops and sub -groups

throughout the UK, Europe and America.

If you'd like more information or details of

membership y ou 're invited to contact Bill Newell

on (01268) 754407.


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15

Elaine Richards G4LFM looksat your letters, has news ofInternational Marconi Dayand has a Maplin clock/timerfor you to win in an easier toenter competition.

Readers' LettersKen Mallett G2AXU haswritten with another solder-ing tip following the pieceabout safety in May. Hekeeps a small aerosol ofBurneze next to the solder-ing iron. Apparently, itdoesn't stop the swearing,but it does ease the pain!Also Acriflex cream is quitegood, but not so convenientto use.

If you've got any tipsyou have picked up over theyears how about passingthem on to the newcomers?Drop me a line.

Tony Mansfield2EOAIR has been a Novicelicensee since August 1994.Since then he has madesome 667 contacts on3.5MHz using c.w., 72 ofthese were with G3 callsignsand 62 with G4 callsigns,even 6 with G2 callsigns. Hehas received kindness, helpand encouragement from allthose he's contacted.

Many have even takenthe trouble to write a letterto send with their QSL card.This is encouraging to hear,as this is what amateurradio is supposed to beabout, everyone helping andsupporting one another.

It's good to hear this sortof story for a change.Thanks Tony for the infor-mation.

2iliggieE0AIR

Different Opinion

For Radio Beginners of all Ages.

Elaine Richards G4LFM, PO Box 1863,Ringwood, Hants BH24 3XD.

Another ElmerNomineeBill Cross GOELZ has beennominated for the ElmerAward by W. G. AndrewsG3DVW. On five evenings aweek, Bill sends out Morsepractice from his home stationwith speeds from first learn-ing to test speed. All this isdespite being permanentlydisabled following a motorcycle accident.

Four new callsigns haveburst onto the air followingBill's help: GOTPJ, GOUGQ,GOVLL and GOULP (and theypassed first time). There arenow four new potential ClassA licensee in the wings prac-tising hard with Bill - G7LPJ,GW7PDC, G1HSC and G7PED.

Thanks for the nomina-tion. If anyone else has some-one they think should be nom-inated for their help in startingamateurs on the road to theirhobby, drop me a line withthe details. Prizes will beawarded around October.

Citizens' BandI've had a couple of good let-ters about CB and CB rigs,but space has run out on me(again). I'll make sure theseget included next month asthe first item. Keep writing!

Someone has disagreed with my view, published in the Feb '95PW, on the Seek You CD (I was fairly sure someone would!).

A FAX got sent to the PW offices with details of a reviewthat appeared in OST (an American amateur Radio publication).It was written by a part-time brass musician Al BrogdonK3KMO who plays Dixieland jazz.

Al says" ...the lyrics, the tunes, the arrangements and themusicianship knocked my socks off! The album has the authen-tic Nashville sound, with top-notch studio musicians....Thisalbum will bring a tear to you eye on those lonely drink -aloneevenings, and it will make you laugh at your ham -radio selfduring happier times "

So, probably the best advice is if you're interested in SeekYou, try and get to one of the larger radio rallies, as that'swhere I've heard it played. Have a listen for yourself and decidewhether you like it or not.

Time CheckWhen you are first starting out inradio, time can be a tricky prob-lem. I don't mean trying to findenough time to do all the thingswe want to - although that is dif-ficult. I mean deciding what timeto put in your log and on the QSLcard.

In radio, everyone usesUniversal Co-ordinated Time(UTC), which is basically thesame as Grenwich Mean Time(GMT). That's all well and good,but when we're in the summermonths, the UK changes toBritish Summer Time (BST). So,looking at your watch isn't any

good, you have to convert toUTC.

Obviously, the easiest way isto have a dedicated clock set toUTC and leave it by your radioand here is what prompted this.I've recently seen a pressrelease from MaplinElectronics of 274-288,London Road, Hadleigh,Benfleet, Essex SS7 2DE withdetails of their MultipurposeI.c.d. clock and timer, costingaround £12.99.

The Maplin clock timer has adual time -zone facility so youcan set it to UTC and put BST inthe second zone for when youneed it. It also has several tim-ing functions that you may finduseful.

Now, I've four of the clocktimers to give away as prizes.They'll go to the first four cor-rect answers, to the questionsbelow, pulled out of my coffeejar.

01: When did UTC replace GMTas the official designation oftime measurement? Was it1900, 1928 or 1955?

02: How many hours in front ofUTC is Wellington in NewZealand? Is it +12, +10 or +13?

Send your answers to theaddress at the head of this col-umn and if you are one of thewinners, your prize will be sentto you. The closing date forentries is May 19. You can, ofcourse, enclose a letter tellingme what you've achievedrecently or anything else too!

International MarconiDay

The InternationalMarconi Day is heldevery year on the third Saturday inApril to commemorate Guglielmo

Marconi, who was born on 25 April1874. So, this year the date to make a note of is April 22. Keep alisten out on the air for any of the 25 special stations that are setcareer.up from places that were of special importance in Marconi's

One of the Marconi Day stations is going to be OE1M and itwill be on the air for 24 hours on April 22 using s.s.b., c.w. andamateur radio satellites. It will be run by Radio AustriaInternational (ORF).The ORF station will also broadcast special programmesdevoted to the International

Marconi Day. Each QS0 or accuratereception report of OE1M and a Radio Austria Internationalbroadcast will be confirmed by a special QSL card.Frequencies to try are: OE1M (s.s.b.): 3.77, 7.07, 14.17, 21.17and 28.47MHz. Via OSCAR 13 (approximately0500-1220) andOSCAR 10 (1300-1500): 145.89MHz. Radio AustriaInternational 5.945, 6.015 10500-0700 via Sackville, Canada),6.155 (0400-2300), 9.655, 9.87, 9.88, 11.78, 13.73 (0000-2400),15.41, 15.45 and 17.87MHz.

The QSL address is: Radio Austria International, A-1136,Vienna, Austria.Special event stations like OE1M are a good way for begin-ners, whether a Novice or not, to get their QSL collection off to aflying start. Fortunately,

special event stations run by largeorganisations usually send their cards quickly and it's veryencouraging to get a few cards to look at.It also gives you something to show the family why youspend hours glued to the radio! Happy listening.


First StepsA Licence, A Callsign, A Rig - Now What?

So, the postman has delivered the all-important piece of paper arid younow have a licence arid callsign. You've even got yourself a rig but nowwhat?

Well, you just switch the rig on and start talking to the world don'tyou? For most of us it's riot as easy as that. It's quite a long time nowsince I first went on the air but I can remember it still quite clearly.

I was very nervous and didn't want to make a mistake. I didn't wantto make a fool of myself either. I also felt a right idiot sat in my bedsitchatting to myself - well that's what it felt like.

I was used to not hearing a great deal of chatting once I got home(same as most who live on their own) and It felt very odd holding aconversation with something the size of a house brick! Still. I was verylucky and met some very nice people on the air in the first few weeks ofgetting my licence arid they made it very easy for me to get Into thehobby quickly.

So, what's the best way of getting your first contact? Well, theeasiest way is to make arrangements with a friend and so you do atleast speak to someone you know on a pre -arranged frequency. This atleast gets you the first entry in your log book.

Another gentle way in is to find another conversation that soundsinteresting, wait until the people involved are winding up the chat andthen call one of them to see if they can spare a little time to talk toyou. This can often work well as you can pick people who have spokenpreviously about something that interests you.

But what about the first CQ (general) call? Use a band plan orrepeater card to make sure you are transmitting on the correctfrequency or portion of the band. Locate the calling channel and listen -

*PRACTICAL WIRELESS & SHORTWAVE MAGAZINE IN ATTENDANCE

April 15: The Spring All Micro Show, Radio Rally &Electronics Fair is being held at Bingley Hall,Staffordshire Showground, Weston Road, Stafford IA518Stafford-Uttoxeter Road), signposted from Junction 14on M6 Admission for adults £2.50, children under 14,50p, concessions - OAPs, RSGB members, student card,UB40, £1.50 The organisers are as usual supportinglocal charity stalls, and there's free parking and alicensed bar from 11am. There will also be refresh-ments, meals and a cafeteria For further details contactSharward Promotions, Upland Centre, 2 Upland Road.Ipswich 1P4 5BT. Tel: (01473) 272002 or FAX: (01473)272008.

April 16: The Cambridgeshire Repeater Group AmateurRadio Rally is being held at Philips Telecom - CateringCentre, St. Andrews Road, Chesterton, Cambridge.Doors open at 10.30am. There will be trade stalls, Bring& Buy and much more Further information can beobtained from Darren Slater G1ERM on (01223) 60601evenings.

April 22: International Marconi Day special exhibitionstation at the Puckpool Park Wireless Museum,Seaview, Isle of Wight. Further information fromDouglas G3KPO (01983) 567665

April 23: The Bury Radio Society will be holding theirannual rally at the Castle Leisure Centre, Bolton St,Bury. Doors open at 11am 110.30am for disabled visitors).There will be a Bring & Buy, a bar and refreshments.Talk -in on S22. Further details are available from G4KLTon 0161-762 9308.

April 23: Lough Erne Amateur Radio Club are holdingtheir 14th mobile rally in the Killyhelvin Hotel, Enniskillen.All radio amateurs and those interested in Electronics

in fact. I would suggest you listen for a little while Just to see who isabout at that time.

If all is quiet then put out your first CQ call, everyone has their ownfavourite way of phrasing it. but something Ilke. 'CO. C.Q. CO this isG4LFM Golf Four Lima Foxtrot Mike G4LFM listening for any call' wouldsuffice. Then sit and listen for any replies.

Po tell people that this is your first. second or one of your firstcalls, then usually they will become very understanding and will guide youthrough your first few days as a transmitting amateur.

Now for a few don'ts. Personally I wouldn't recommend an audience;or the first few calls, if you make a mistake that only makes it worseand can get you flustered.

Don't Just switch on your rig, select a frequency and start talking,No-one likes being rudely interrupted.

Don't join another conversation without being invited, it's Just badmanners. In a pause between 'overs. announce your presence and thenwait to be asked to join in. If those talking won't let you in, then theirconversation isn't interesting enough to want to Join!

Finally, above all. stay calm. It is a hobby and your whole life won'tcrumble if you make a few mistakes in the early days. Don't let youmistakes become bad habits and you'll soon get to know the regulars.perhaps on the local repeater. Before you know it you'll be the old handtalking to the 'new boys' with their brand new callsigns.

Until next time, keep 'Nattering' and don't forget I'malways interested in your suggestions andideas for this column.

If you're travelling a long distance to a rally, itcould be worth 'phoning the contact number to

check all is well, before setting off.The Editorial staff of PW cannot be held

responsible for information on Rallies, as this issupplied by the organisers and is published in

good faith as a service to readers.If you have any queries about a particular

event, please contact the organisers direct.

actixe,Q4101

OF'

and Computing are cordially invited to the rally. Theusual traders will be attending and there's also a Bring& Buy. Door tickets will be included in the raffle forworthwhile prizes. For more details contact Fred GI4PCYon 101365) 324993

April 23: Swansea Amateur Radio Society are holdingtheir Amateur Radio & Computer Show in the SwanseaLeisure Centre, which is located on the 44067 Swansea -Mumbles coast road. Doors open at 10.30am. There willbe trade stands, a Bring & Buy, operational h.f. and v.h.fstations, S22 talk -in using GB2SWR plus full catering.Roger GW4HSH on (01792)404422.

May 6: The Dartmoor Radio Rally is being held atYelverton Memorial Village Hall. Meavy Lane, Yelverton,Devon. Doors open at 10.30am. There is enough parkingfor 600 cars with access for disabled visitors. There isalso a playground for children, trade stands, a Bring &

Buy and refreshments, etc. Talk -in on S22. For furtherdetails contact Ron on (01822) 852586.

May 14: The Dunstable Downs Radio Club are holdingtheir 12th Annual National Amateur Radio Car Boot Saleat Stockwood Country Park, Luton, Nr. Jn. 10 Ml. Doorsopen 10am until 5pm. Talk -in on 144MHz. Attractionsinclude open day, environmental exhibits, side stalls,and free entry to the Mossman collection of horsedrawn vehicles, craft museum, train and carriage ridesplus much, much more. Ken Brewer on (01582) 451057.

May 14: The Drayton Manor Radio and Computer Rally isto be held at Drayon Manor Park Zoo, Pazbly, Tamworth,Staffs on the A4091. The main traders will be in fourmarquees. There will be an outside flea market, largeBring & Buy stall, local clubs and special intereststands. Doors open at 10.30am Make it a day out for althe family Norman G8BHE 0121-422 9787 or PeterG6DRN 0121-443 1189 evenings please

May 20: The Ipswich Computer Show is being held atWillis Corroon Sports & Social Club, The Street,Rushmere St Andrew, Ipswich. Entry fee for adults is£1.50 on the day Children under 14, OAPs, UB40 andwheelchair users only 50p. Doors open 10am to 4pmFree parking. Sharward Promotions on (01473) 272002 orFAX: (01473) 272008.

May 21: The 11th Yeovil QRP & Construction Conventionis being held at the Preston School/Centre, Monks Dale,Yeovil, Somerset. Doors open at 9am. Admission is f1.75.There is a free car park and refreshments all day. Theconvention will be preceded by a Morse Fun -run oneach evening from Tuesday 9 to Friday 12 May. Furtherdetails can be obtained from G3COR, OTHR. (01935)813054.


President VisitsThe Hoddesdon Radio Clubare very much looking forwardto the visit of the RSGBPresident, Clive TrotmanGW4YKL, on April 13. Meetingsare held at the ConservativeClub, Rye Road, Hoddesdon,Herts from 8pm.

Now in its third year, theHoddesdon Radio Club contin-ues to increase its membershipand caters for all aspects ofradio. The club especiallyencourages wives, girlfriends,etc., hence the talk this monthis 'Orchids of the World' byFrank GOKUQ.

Yeovil VE DayThe Yeovil Amateur

Radio Club will be staginga display of Vintage andSecond World War radio

equipment and operating aSpecial Event Station to cel-ebrate the 50th anniversaryof Victory Europe (VE) Day

on Monday May 8 1995.The event will be in col-

laboration with YeovilDistrict Council, who plan tostage a whole day of cele-bration and thanksgiving.The day will start with reli-gious services in the morn-ing, through to firework dis-plays and dancing to GlenMiller style music in the

evening.The Yeovil ARC will be

holding the usual annualseries of classes, in prepara-tion for the December Radio

Amateurs Examination.Enrolment night for the

courses will be on ThursdayMay 11 at 7.30pm or any

time up until 10pm. The 11thAnnual QRP Convention willtake place on Sunday May

21. Doors open at 9.30am atthe usual venue which is atThe Preston Centre, Preston

Road, Yeovil.Later on in the year on

July 30, there is a BBQ andFun Day For All at the QTH

of Tim Walford G3PCJ(Upton Bridge Farm, Long

Sutton, Langport,Somerset). Tim G3PCJ host-ed a similar event last year,when a good time was hadby all, despite the weather!All radio clubs within easyreach are cordially invited.

Bring your rigs or just comeand meet up with friends.

Further details of theabove activities can beobtained from Cedric

White, QTHR or by tele-phoning (01258) 473845.

Send your information to the 'Club Spotlight'newshounds Donna Vincent G7TZB and

zoe Shortland at the PW Offices.

Members UniteThe members of the North Ferriby United ARS INFUARS)recently competed for the G3YCC Award, which on this occa-sion, was for having QSOs on 144 and 430MHz. Ken G4VKKwon the award, for the second time, in the most recent com-petition.

Michael 2EOAHY was presented with a special certifi-cate, signed by the committee, commemorating being thefirst Novice licensed member of NFUARS. Michael, aged nine,passed his Morse test at seven and enjoys c.w. contacts onthe bands, encouraged by his father, Mike G4VHM.

If you would like to get involved with the North FerribyUnited ARS, you can contact the club's Chairman, Mr F. W.Lee G3YCC.

Members of the NFUARS (I_ to RI: Malcom G4XWA(Club Vice Chairman), Frank G3YCC (Chairman), KenG4VKK and at the front, Michael 2EOAHY.

Established WarringtonThe Warrington AmateurRadio Club is a long estab-lished club with about 50 mem-bers. Meetings at theGrappenhall CommunityCentre, Bellhouse Lane,Grappenhall, Warrington areheld on Tuesday evenings at8pm. Radio AmateursExamination (RAE) courses andMorse practice sessions arealso available at this location.

Talks are often arranged,covering subjects such as tech-nical topics, operational issuesand general interest. The

Warrington ARC also take partin outside events including anannual Fox Hunt.

Throughout the year thereare a number of social occa-sions, and at all times, theWarrington ARC aim to pro-mote a friendly and co-opera-tive atmosphere for membersto meet and exchange informa-tion and discuss any problems.

Further details can beobtained from the SecretaryJohn Riley GORPG on(01925) 762722

Your page - your story!

The local Amateur

Radio Club is seen by

many as being the

`backbone' of our

hobby. There are some

interesting stories to be

told. So, let's hear

about your Club histo-

ry, share the informa-

tion and you'll probably

recruit new members at

the same time! Editor.

Braintree OnThe Ball

The Braintree & DistrictAmateur Radio Society

meet on the 1st and 3rdMondays of the month atThe Clubhouse, Braintree

Hockey Club, Church Street,Bocking. Doors open from7.30pm for an 8pm start to

the meeting.Prior to 8pm, and during

the refreshment break,members have the opportu-

nity to sell or exchangeequipment, etc. Meetingsnormally end at around

10pm.The Club Membership

fee is £12.50 annually.Senior (retirement age) andJunior (under 18) memberspay a reduced club subscrip-tion of £6.25. Door fees arepayable per meeting. Ratesare 60p for members, 30p

for juniors and senior mem-bers, and 80p for visitors.However, the fees for visi-tors under 18 and in full-

time education is only 40p.A Club Net is operated

on 144MHz on the 2nd and4th Mondays (excludingBank Holidays) under the

callsigns G6BRH andG4JXG. The net commences

at 2000 clocktime on S15 -145.375MHz, unless QRM.

The Braintree & DARSalso produce a magazine

BARSCOM which is issuedfree to members, usually at

the first meeting of themonth.

To find out more youcan get in touch with the

club's Secretary JohnButton G1WQQ on(01787) 460947.


Official OpeningThe Pontefract & DistrictAmateur Radio Society openedtheir new shack back in December1994. The Rev. George Dobbs,accompanied by his wife, per-formed the official opening. Alsoin attendance were Mr & Mrs PeterSheppard the RSGB zonal councilmember for the North of England.About 30 club members andfriends attended, and enjoyedplenty of good food and a friendlyatmosphere.

The other highlight of the daywas a presentation ceremony tohonour long serving members:Brian Booth G3SYC, NiallWhittingham G4ISU and WalterFarrar G3ESP. They eachreceived a long service certificatepresented to them by the Rev.George Dobbs.

The new shack was builtentirely by club members, andwas paid for with the moneyraised by them. For more informa-tion on The Pontefract & DARSyou can contact Colin B.Wilkinson on (01977) 677006.

International Marconi Day - April 22 1995

The first InternationalMarconi Day event run by theCornish Radio Amateur Clubtook place in April 1988 andsince then has made greatstrides, going from strength tostrength. The 6th InternationalMarconi Day event in 1993 hadsome 25 participating stationsfrom all around the world.

In 1994, the numberincreased to 36 and some 260awards were claimed. If allgroups expected to take part in1995 confirm, the total will riseto 46 stations.

Originally, the CornishRadio Amateur Club decided tolimit the total number ofInternational Marconi Day sta-tions to a maximum of 30, butwith numerous approachesfrom other groups wishing tojoin, they have relented.Although the organisationalworkload will increase some-what, the club feel they will beable to cope (Good luck tothem! PIM.

To date, the Cornish RadioAmateur Club have issued inexcess of 800 of their specialaward certificates, which are ofhigh quality and well worth any-one's efforts to earn. Therequired standard for the April22 event is to work 12 of theparticipating stations.Alternatively an award isoffered to the short wave listen-er (s.w.I.) for logging 12 of theInternational Marconi Day sta-tions.

Operation will take part for

the 24hr period from000/2359UTC on Saturday April22 1995. The main mode ofoperation will be on s.s.b. on allh.f. bands with periods of c.w.or digital modes of communi-cating being actively encour-aged.

For the transmitting stationclaimant, the cost for the awardis £3.50 (UK), $10 (US) or 12IRCs. For this you require con-tacts with a minimum of 12 ofthe participating stations work-ing two-way on any modeemployed. Only one contactwith each participant will counttowards the award, so a contacton two bands or on two differ-ent modes will count only asone contact.

For the s.w.I., the awardcosts are £3.50 (UK), $10 (US) or12 IRCs. For this award you arerequired to have logged 12 two-way QS0s and provide a fullextract from your listeners log.

Mixed modes and bands areallowed, but each callsign willbe counted just once towardsthe minimum of the 12required.

All award claims should bemade in writing giving a fullextract of log entries to: SueThomas GOPGX, CornishRadio Amateur Club, IMDAwards Manager, PO Box100, Truro, Cornwall TR11RX.

The listeners award is opento all, so if you only manage to

Top: Grand opening of thenew shack. (L to RI ColinWilkinson GONQE and Rev.George Dobbs G3RJC.

Bottom: Recipients of thelong service award IL to RIWalter Farrar G3ESP, BrianBooth G3SYC and NiallWhittingham G4ISU.

CallsignAllocatedDo you remember reading inthe March Issue of PWthestory on the Liberation ofGuernsey? Well, 'ClubSpotlight' has recentlyreceived good news that theGuernsey Amateur RadioSociety have now beenallocated a callsign, which isGB5OLIB.

Want to know moreabout the special event sta-tion in connection with the50th anniversary of theLiberation of Guernsey?Then why not contact PhilCooper GUOSUP on(01481) 700700.

have a QS0 with 10International Marconi Day sta-tions, but hear QSOs for at leasttwo more, then you will be eligi-ble to claim the award as a lis-tener.

The Radio Society of GreatBritain will be running an offi-cial International Marconi DayStation (callsign to be con-firmed) in tandem with theAnnual Open Day at LambdaHouse, the RSGB HQ.

The stations to listen out foron April 22nd 1995 are asshown in the table below.

The entries marked ' havenot yet confirmed their partici-pation to the Cornish RadioAmateur Club, although theyare expected to be on the air onInternational Marconi Day onApril 22nd 1995, the eighthevent - so don't forget it!

CT1TGM Coimbra, Portugal DAOIMD Borkum IslandE12IMD Crookhaven, Eire' EI3MFT Letterfrack. Co. Galway, EireE14IMD Clifden, Galway. Eire EI4JAM Whiskey Corner. DublinE15IMD Cork, Eire ED7IMD Cadiz, S. SpainGBOIMD Alum Bay, Isle of Wight GBOMAR Puckpool Pk, Isle of WightGBOMWT Chelmsford GB1IMD Leicester ISatellitesrGB2GM Poldhu Cove, Cornwall GB2IMD Rathlin Is'GB2MDI Pepperbox Hill, Salisbury GB2MID Sandbanks, Poole, DorsetGB2SFL South Foreland Lighthouse GBOIMD Truro Ithe CRAC Station)GB4JAM Isle of Wight GB4MD Old Carnarfon Stn., Waunfawr'GB4MDI Lavernock Point, S. Glamorgan GB??? RSGB. Lambda House, Potters Bar!YOGA Sardinia Island' 1???? Caselecchio Di Reno'IYOORP Rocca Di Pappa, Rome' IYOTCI CivitavecchiaIYITTM Sestri Levante, Genova IY4FGM Villa Grifone, PontecchioIY1MR Rapallo, Genova K1VV/IMD Cape Cod, MassKK61-11IMD Marshall, California 0E1M Radio Austria Int., ViennaPQ1MD Rio De Janeiro, Brazil PRI MD Rio De Janeiro, Brazil'PS1MD Rio De Janeiro, Brazil' PT 1 MD Rio De Janeiro, Brazil'PUIMD Rio De Janeiro, Brazil PV1MD Rio De Janeiro, BrazilPW1MD Rio De Janeiro, Brazil PX1MD Rio De Janeiro, Brazil'ZW 1TTO Rio De Janeiro, Brazil ZW1USK Rio De Janeiro, BrazilVEIIMD Glace Bay, Nova Scotia VK2IMD Wahroonga, New S. WalesVO1IMD St Johns, Newfoundland ZS6IMD Johannesburg, S. Africa'


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INSPECT Zli;Richard Newton GORSN has tried the newly -introduced FT -51R transceiver from Yaesu andfinds there's a large number of interesting facilities built-in to a small package.

The Yaesu FT -51R is a dual bandtransceiver covering 110-180MHzand 420-470MHz on receive and144-148MHz and 430-450MHz ontransmit. It creates an excellent first

impression. The radio is supplied with a helicalantenna, belt clip, and drop -in charger unit. Thisall goes to make up a very professional lookingpackage.

The Yaesu FT -51R comes with an extensivehandbook and a quick reference guide. Thehandbook I found to be confusing, poorlywritten and far too complicated. This is in starkcontrast to the radio, which proved itself to bevery pleasant and easy to use.

Smartly Finished

The Yaesu FT -51R is smartly finished in highimpact plastics and metal. It's very small butmaintains a good solid feel to it.

The display is large and the main functionindicators are easy to read. However, theindicators for less used functions are not so easyto see.

On the top panel of the Yaesu FT -51R are thespeaker/microphone sockets. The top panel isalso home to the BNC antenna connector and alarge rubber covered rotary knob.

The rotary knob is used to move through thev.f.o. range and memories. It's also used totoggle through various functions such as the set-up menu and CTCSS tones.

On the left side panel (as the unit faces theoperator) the p.t.t. button can be found. This is arubber covered push -to -make switch, andincorporated in this is a second switch thatwhen operated transmits a constant 1750Hztone burst.

My fear was that this would be easily pressedwhen not required. However, it is so positionedthat this did not occur. Even with my largeclumsy fingers!

The Sub Band button momentarily switchescontrol from the current operating band to the

other band. For example, enabling you to lowerthe volume on the sub band while stilltransmitting on the operating band.

The power On/Off button is covered in vividorange hard rubber (this is in contrast to theother controls which are all black). The powerOn/Off is also flush with the body of the radio toensure it cannot be accidentally pushed.

All the controls on the side panel aredesigned so that they need gentle but positivepressure on them to switch. And in fact, I feel itunlikely they could be accidentally operated.

The front panel of the Yaesu FT -51R is hometo remainder of the controls. The Volume andSquelch are controlled by the same two buttons,in a rather unusual way. They are in the form oftwo press buttons, one up and one down.

I also found that the Lamp button is wellrecessed. This turns on a very effective greenback light that lights up the large display and allprimary function and DTMF number keys.

Splendid Ergonomic Design

The splendid ergonomic design of the Yaesu FT -51R is only one of its attractions. The Yaesu FT -51R also has an advanced use of DTMF toneswhereby it can send and decode short messagesusing the tones!

The transceiver displays the messages one ata time on the large I.c.d. display. Messages suchas 'Ring me' or 'At home' can be received andheld in memory. The user can then togglethrough them to get a complete message suchas: 'Richard - Ring -Me -At -Home -Tonight -Cheers -Clive'.

The Yaesu FT -51R also uses DTMF for thefamiliar paging facility. This is where you canpage individuals or groups of people withequipment with the same facility.

Message And Paging

I have owned a hand-held with DTMF messageand paging facilities for threeyears now, and as yet I havenot used either in anger.However, I can see that insome circumstances bothwould be very useful,perhaps at a rally for bargainhunting or on a RAYNETexercise.

Nowadays CTCSS squelchcontrol is becoming verypopular due to the increasedactivity in some areas.Because of this, I think it'swonderful to see a hand-heldthat offers CTCSS encode and

The battery pack with integral rearcover illustrating the heavily gold plated contacts.

decode as standard, instead of selling the latteras an optional extra. Well done Yaesu!

Spectrascope Feature

The Yaesu FT -51R also incorporates a'Spectrascope' feature. This allows you to viewactivity on the channels above or below thecurrent operating v.f.o. frequency.

With the 'Spectrascope' facility (if it's inmemory mode) the transceiver will display theactivity on the adjacent ascending anddescending memories. This could be useful ifyou're monitoring local repeaters.

Another facet of the Yaesu FT -51R design thdireally caught my eye was the fact it will receivein amplitude modulation (a.m.) mode anywherein its v.f.o. range. And although it's not unusualfor a modern hand-held to receive the 'Air Band'in a.m., that's normally as far as a.m. coverageextends.

The Yaesu FT -51R can be toggled to a.m.reception on any frequency. I liked this becausedown my way there's an increasing number ofpeople going back to a.m. on 144MHz due tothe cheaply available second-hand equipment.It's terrific to be able to receive them, and if theyhave receive on 433MHz it's great fun to have across band, cross mode QSO!

The Yaesu FT -51R also has a full or semiduplex facility. When in full duplex, the radioautomatically adjusts the received audio level.

The microphone is also well situated forhand portable and duplex operation in mind. It'sright at the bottom of the radio, thus cuttingdown on feedback and making the transceivereasier to operate, as it can be held like atelephone.

On Board Help

One thing that is worth a mention is the YaesuFT -51R on board help facility. When you selecta function the radio automatically starts scrollinga user help message across the screen tellingyou what you should be doing. This can bedisabled when you have mastered the radio or ifyou just like giving yourself a hard time!

Many of the functions on the Yaesu FT -51Rcan be customised by the user. For example,these include transmit offset, channel spacing,key bleeps, bell alerts and scan modes to namebut a few.

Transmit Output

The transmit output power is also very versatileon the Yaesu FT -51R. With the supplied batterypack it can be switched between the high power


Manufacturer's Specifications

GeneralFrequency range (RX)Frequency range (TX)Channel stepsSupply voltage:Current Consumption:

Auto Power Off:Stby (Saver on):Stby (Saver off):Tx ([email protected]):Antenna (BNC):Case size (WHD):Weight (approx.):

ReceiverCircuit type:Intermediate Frequency:

12 -dB SINAD Sensitivity:Adjacent channel selectivityIntermodulationAF output:

TransmitterRF output:EL:

11:L2:L3:HI:Frequency Stability:Modulation system:Maximum deviation:FM noise (0 1 kHz):Spurious emissions:Microphone type:

Yaes110-180MHz 420-470 MHz144-146 and 430-450 MHz5, 10, 12.5, 15, 20, 25, and 50kHz4.0-12V d.c.

v.h.f u.h.f.200uA 200uA25mA 23mA (34mA dual-rx)52mA 49mA (85ma dual-rx)<1.6A <1.9A500 - YHA -55 helical supplied57 x 123 x 26.5 mm330 grams with battery pack FNB-31 and antenn.

Double -conversion superheterodyne45.05MHz and 455kHz (v.h.f)58.525MHz and 455kHz (u.h.f)< 0.158 uV (v.h.f) and < 0.180 uV (u.h.f)> 65 dB (v.h.f) and > 60 dB (u.h.f)> 65 dB (v.h.f) and > 60dB (u.h.f)0.2 W @ 8 Ohms for 10% THD

With supplied battery pack.20mW0.5W1.5W2.0W (1.5W on u.h.f.)2.0W (1.5W on u.h.f.)Better than ± 5 ppmVariable reactance±5kHzbetter than -40dB 1 kHz> 60 dB below carrier2k12 condenser

setting of 2W (1.5W on u.h.f.) through 1.5W,500mW and down to an extra low of 20mW.

It would seem that there's no provision forthe Yaesu FT -51R to be operated from anexternal power supply. This surprised me.

You can however purchase a mobile chargerthat doubles as a d.c. supply and mountingcradle. Using this will give 5W out on highpower. There are also different battery packsavailable, one of which will allow 5W output.

Liked The Transceiver

I must say that I liked the Yaesu FT -51Rtransceiver! I must confess however, the bigselling points did not impress me that much, butthe small attentions to detail did.

The small attention to details whichimpressed me included: The facility that can beset to enable the display light to automaticallycome on when a station is found in scanningmode. I also liked the neat and tidy way the

cover for the speaker/microphone folds over andthe large well labelled and thoughtfully situatedcontrols. They are all features that endear thislittle radio to me.

I must also congratulate Yaesu on designing aradio with a 'wide' front-end that seems to rejectinterference well! The supplied helical antennaalso gets my vote. Although it may well be oneand half times the length of the radio, it'scertainly not like the 'dummy load' you often getwith some radios!

The Yaesu FT -51R is a small, well built anddespite its handbook, an easy to use hand-held.Its advanced features can be used or ignoreddepending on what your needs are.

Whatever you use the Yaesu FT -51 R for, I'msure you will not be disappointed. My thanks forthe loan of the transceiver go to Barry Cooperof Yaesu UK Ltd., Unit 2, Maple Grove BusinessCentre, Lawrence Road, Hounslow, Middlesex1W4 6DR. The FT -51R is available fromapproved Yaesu dealers for £499.

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After seeing a copy of the GORSN reviewBarry Cooper of Yaesu UK Ltd., sent us thefollowing comments:

When given the chance to comment on areview, it is difficult not to become overprotective of your 'new baby'. Any parentwill know how quickly the hackles riseshould anybody dare to criticise anoffspring, whether or not criticism isjustified! I guess this is what makesequipment reviews so popular. I digress ...

I am pleased that Richard GORSNfound so much to like about Yaesu's newdual -band paging transceiver. He states thathe found the handbook confusing, poorlywritten and too complicated. Whilst Irespect the reviewer's opinion, I must takeissue with it.

The handbook is comprehensive, wellillustrated and detailed. It is well written inconcise English, pleasingly devoid ofAmerican spellings and transliterationsfrom the Japanese prevalent not so manyyears ago. The FT -51 R has myriad offeatures and to do these the injustice of lessthan a full explanation would be adisservice to a very complex product.

Richard comments that the majorfeatures did not impress him but the smallattentions to detail did. This is surely how itshould be - something in the product foreverybody.

Barry Cooper G4RKO


Ar2121.1.1.21

As this is our`Computing InRadio' special,Mike RichardsG4WNC hasdevoted hiscolumn to areview of aspecialisedamateur radiocomputer fromFuture BusinessSystems Ltd. AndMike says "Ifyou're thinkingof getting acomputer forradio work butnot sure whereto start, readthis first"!

lot

Fig. 1: The heavily populated but clearlylabelled back panel of the PBS PC.

If you've ever looked throughthe numerous computermagazines trying to find acomputer for radio work you

could be forgiven for beingconfused. The IBM PC clonemarket is still thriving andresults in a mass of glossyadverts all claiming theirmachines are the best.

Even if you read the reviewsto find the best machine, will itbe any good for the specialisedapplications used by radioamateurs? Once you've got pastthis stage and bought the idealcomputer you still have a lot ofwork to do before you can use iton air.

Is this story soundingfamiliar or perhaps daunting?Well. Martin Rhodes G3XZOManaging Director of FutureBusiness Systems decided todo something about theproblem.

As a keen DX enthusiastMartin is well placed tounderstand the needs of a radioamateur. Put this together withthe fact that his company havebeen building IBM clones since1988 and you have a potentially

.5+

winningcombination.The computerI've reviewedhere is one ofa range ofcustom unitsavailable fromhis company.

ReviewModel

The reviewmodel wasbasically a486DX2/66multi -media PCwith CD-ROM.4Mb RAM andsound boardwith internalspeakers.Whilst that'sfine if you'reinto computersit doesn't helpthe newcomer -so what does itall mean?

The 486DX2/66 means thatthe PC uses an Intel 486processor device which runs atdouble the normal (33MHz)clock rate, e.g. 66MHz. The 486processor used represents oneof the fastest processorsavailable, so the computer isvery up-to-date.

The 4Mb of RAM (RandomAccess Memory) is about thelowest you should run with thistype of processor and you maybe well advised to buy an 8Mbversion if funds allow. Theinclusion of a CD-ROM drive letsyou take advantage of all thenew CD-ROM based softwarethat's available, while the soundboard lets you use the computerto both record and playbackhigh quality audio.

The built-in sound boardalso has the benefit of givingyou great sound with any gamesyou might use. So, you can see.this basic computer set-up isup-to-date and is likely to serveyou well for non -radio uses aswell.

Special HardwareIn addition to the basic featuresI've mentioned so far, the

computer is fitted with somespecial hardware and softwareto customise it for amateurradio use. At the heart of this isthe ShackMaster unit which isbuilt into one of the disk drivebays on the computer frontpanel.

The custom made unitprovided control of a wide rangeof radio related functions. Oneof the objectives of creating thespecialised radio computer wasto try and get rid of the 'rat'snest' of wires and boxes thatyou often find at the back ofmany radio set-ups.

The front panel of theShackmaster unit is quite busyand packed with a host offeatures. The main elementsare a 1200baud v.h.f. PacketTNC, audio switching betweentwo rigs, Serial port levelconverter, c.w. rig keying, banddata import plus a voice keyingsystem.

All the connections to theShackMaster were handled viathe appropriate interface cardsat the rear of the computer. Theonly exception to this was themicrophone in and out socketsthat were mounted on the frontpanel.

While the 'mic in' was fine I


:s121:1_14 L'ILIJALLILT21 JJ EL,1211-2J

Manufacturer's SpecificationsHardwareProcessor 80486DX2/66 cpu with 256kb cache

RAM Memory4Mb RAM expandable to 48Mb

Disk drives

Extensions

Hard Disk 420MbFloppy 1.44Mb 3.5inDual speed CD-ROM drive

1Mb SVGA video boardSoundBlaster stereo sound card2 x parallel ports4 x serial ports

Video 14in SVGA low radiation colour monitor

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Shackmaster 1200 baud TNC-2 type Packet controller with mailboxVoice keyer for digital recording playbackRS -232 - TTL level convertor for rig controlAudio monitoring/analyser switching for two transceiversc.w. rig keying via LPT portBand data import

Software DOS and Windows installedVoicekeyer control software

Fig. 2 (above): Screen grab fromthe Turbolog system (see text).

Fig. 3 (top right): A Packet DXcluster screen grab (see text).

Fig. 4 (right): The Rig-EQF program gaveG4WNC comprehensive control of the

Kenwood TS -850 (see text).

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felt the 'mic out' socket wouldbe better placed somewhere onthe rear panel. However, Isuspect the decision to placeboth sockets on the front panelwas done in the interests ofkeeping computer noise wellaway from the sensitivemicrophone signals.

The ConnectionsBefore I go on to cover thevarious features in detail, let'sjust run through theconnections that need to bemade to get the systemrunning. In this section I'massuming you have an h.f. rigthat includes remote controlfeatures and a v.h.f. rig forpacket operation.

On the front panel the onlyconnections are the microphoneinput and output as I describedearlier. The remainingconnections were all neatlylabelled on the rear panel.

Anyone with experience incomputers will appreciate thisas all too often you have tomake an educated guess as tothe purpose of the varioussockets! The main remotecontrol link to the h.f.transceiver is the only speciallead required and this isordered to suit the transceiver.

In my case I was using aKenwood TS -850S h.f.transceiver. The lead I usedcomprised a 15 -way Dconnector at the computer anda DIN and standard jack plug forthe CAT and keying connectionto the transceiver.

A standard lead with a3.5mm jack at each end is also


needed to provide a receiveaudio feed to the computer.Connecting the v.h.f. transceiverwas also very straightforwardand used just three single leadsfor receive audio, transmit audioand the p.t.t. line respectively.

With the essentialconnections completed, the endresult was certainly very muchneater than the usual 'ratsnest' associated with anadvanced station set-up. Inaddition to the radioconnections on the rear panel,there were the usual input andoutput ports for printer andserial data.

The serial output could beset to COM3: or 4 with COM3:being the preferred option. Oneof the great advantages of acomprehensive set-up such asthis is the ease of installation.Anyone who's tried to get allfour COM: ports working todifferent applications will knowwhat I mean!

One final optionalconnection was a power feed tothe Packet TNC. This was usefulfor those that want to keep theTNC running when the PC isturned off.

The TNC required just 6 to12V d.c. connected via a3.5mm jack on the rear of thePC. Just a word of warning here- there are six of these jacks ina neat line on the rear panel sobe very careful to make sureyou pick the right one! They areall sign written so there's noexcuses'

Audio MonitoringThe routing of all the audio

signals through the computerenables simple monitoring ofthe transmit and receive signalsfrom both transceivers. Thismonitoring was controlled bytwo toggle switches on theShackMaster unit.

The first switch was used toselect either rig 1 or 2, whilstthe second selected betweentransmit or receive monitoring.In later versions this set-up willbe changed to include a centreoff position to facilitate non -radio use of the internal soundboard.

Depending on the setting ofthe Sound/CD switch on thefront panel the audio is passedthrough the internal amplifierdirect or via the sound board.Although not yet implemented,the routing of the signal via thesound board gives anopportunity to add somesophisticated signal processingas the sound board containsdigital signal processingcircuitry.

In addition to providing asubstitute for an externalspeaker, diverting the audio viathe computer gives a muchhigher output power which couldbe great for special eventstations.

The ability to monitor the

transmit signal, whilst not reallyrelevant for microphoneoperation, was very useful fordata work. At the flick of aswitch you could quickly checkthe quality of the audio feed tothe transceiver.

Recording AndPlaybackBy comoining the audiomonitoring, sound board andthe computer's large memoryShackMaster includes a digitalrecording and playback system.The software for this in thereview model was calledVoiceBlaster, but FutureBusiness Systems are currentlydeveloping their own system toprovide similar facilities.

The supplied VoiceBlastersystem operated in thebackground and was activatedusing the Fl - F7 keys. Thebasic record and playbackfeature provided was verysimple but alsoextremely useful.

Pressing the shiftkey followed by afunction key put thesystem into recordmode with the sourceof the recording beingdetermined by the

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SECOND-HAND EQUIPMENTStandard C78 70cms FM portable/mobiletransceiver, c/w matching 10w linear andmobile mount. £249.00

Yaesu FT -102100w+ HF Transceiver, c/wmic, manual and mains lead £499.00

Tokyo HL66V 60w 6 metre linear. £75.00

Icom IC -251E 2m Multimode Base Station.(Excellent radio) £499.00

Alinco DJ -180 2m handheld c/w box.manual. charger. nicad pack and aerial £149.00

Daiwa LA2035 30w 2m linear. £51.63

PK-88 Packet TNC.. £119.00

Daiwa PS -30X1130 amp power supply,variable voltage. (As New) £119.00

Kenwood TS-450SAT HF transceiver,general coverage receive, fitted with autoATU. (THIS UNIT IS UNDER 12 MONTHS

OLD AND IS AS NEW. COMPLETE WITHBOX AND MANUALS) £1135.00Yaesu FT -1000 HF transceiver, generalcoverage receive. (THIS UNIT IS INMINT CONDITION. RADIO IS COMPLETEWITH BOX AND MANUALS AND HAS HADTHE SMC IMPROVEMENT MODS FITTED.THIS UNIT HAS TO BE SEEN TO BEBELIEVED, A REAL BARGAIN) £2499.00

YAESU SP -5 Matching external speakerfor the FT -1000. Speaker has audio filtersand would be a worthwhile accessoryfor any HF station. £80.00

Icom IC -73080 -10m amateur band HFtransceiver 100w output, this rig is idealfor someone new to the hobby £399.00Yaesu FT -1 HF transceiver, generalcoverage recieve.100w output, all modeswith built in power supply, these are stilla superb radio to use £799.00

MFJ-941D 160-10m amateur band 300wantenna tuner £90.00

Kenwood TS -680S HF transceiver, generalcoverage receive with 6 meters. 100woutput on HF,10w output on 6 meters £699.00

Shure 444D Desk mic. (Fit this to your rigand see how your tx audio improves) £79.00

Kenwood PS -30 power supply. Will powerany Kenwood HF rig. £90.00Kenpro KP-100 Auto CW keyer withbuilt-in key £49.00

Yaesu YS -60 HF SWR/Power meter. £49.00

Icom IC -505 6 meter multimodetransceiver, 10w output £390.00Trio TS -430S HF transceiver, generalcoverage receive, all mode, 100w outputcomplete with matching PS -430power supply £585.00MFJ-948 1.6-30Mhz amateur band 300want tuner (Shop demo model full wananly). 1129.00Yaesu FT-209RH 2m handheld c/w nicadpack and charger £145.00

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1.9_11.142_111J14121 J21 21a121121

Sits & Bytesetting of the audio monitorcontrols described earlier. Therecording was started with apress of the Enter key andthere was a handy on -screenbargraph showing the progressof the recording. The recordingwas finished by pressing theESC key.

The flexibility of themonitoring controls meant thatyou could record your ownmessages for later transmissionor even record transmissionsoff -air. Once a recording hadbeen made playback could bestarted by just pressing theappropriate function key. Thisvery simple to use system wasextremely useful in practice.

The most obvious use is topre -record your CQ call so youcan call at the press of a key! Italso effectively replaced theshack tape recorder for shortduration recordings. In my teststhe basic memory configurationprovided enough room foraround two minutes ofrecording.

Rig ControlNext in the armoury of controlfeatures was the built-in rigcontrol circuitry. The circuitrywas directly associated withcommunications port COM4:and included TTL levelconversion for some of thecontrol lines.

The conversion is requiredto change the higher RS -232voltages down to the 5V limitsrequired by the CAT inputs ofmost transceivers. The modifiedoutput from the level converterwas wired to a D -typemiscellaneous connector on therear panel. To link thisconnector to your transceiveryou could either wire your own

or purchase a ready made leadfrom Future Business Systems.

To make use of the controllink you will also need somespecial software designed foryour transceiver. The reviewcomputer was supplied with acopy of the shareware programRig-EQF (Fig. 4) for controllingKenwood transceivers.

The straight forward DOSprogram providedcomprehensive control of theTS -850S from the computerkeyboard. In addition to offeringfull control it also polled thetransceiver every second or soto check for any changes. Thismeant that you could operatethe rig either from the keyboardor directly and the computerwould keep in step.

Just to complete the rigcontrol facilities the computeralso included a level converterfor c.w. keying. There are alsoconnections for downloadingband data from manytransceivers.

Packet Terminal

Just to complete the picture,

After seeing a copy of the G4WNCsent us the following comments:

the ShackMaster included a fullfeatured Packet TNC.The TNCwas permanently connected tocommunications port COM2:with the audio being wired tothe Radio 2 connections on therear panel.

The TNC was a TNC-2compatible unit featuringPacComm firmware with a built-in mailbox. There is little reallyto add, except that it workedfine and was a very neat way tobuild a TNC into your set-up.

Radio Software

You've probably gathered bynow that the computer comeswith very little in the way ofradio software. This is noaccident as the choice ofsoftware package is very muchdown to personal preference.

There are so many goodpackages around that you needto carefully consider which isthe right one for you. Oneexample of a well thought outsystem is TurboLog (Fig. 2) thatwas supplied loaded onto thereview computer. This is

review Martin Rhodes G3XZO

In response to Mike G4WNC 's comment about the position of the 'mic out'socket, I share his view that this would be better placed at the rear of thePC. If this can be achieved without introducing computer noise into the miccircuitry (and if we can find somewhere to put it on an already heavilypopulated back -panel) then this will be implemented.

The ShackMaster unit is available separately - subject to model andspecification of the existing computer. We will also be including free with thePC (subject to normal registration/update charges) the following software:

Super -Duper h.f Contest Logging Programme; Super -Duper IOTA ContestLogging Programme; Super -Duper IOTA for Listeners by kind permission ofEI5DI. RigMaster for Windows - combined TNC and rig control for DXClustermonitoring by both operators and listeners by kind permission of GOCDO.

Finally a full -function combined station and contest logging programmefor Windows is currently under further development which will fully exploit thefeatures of the PC and ShackMaster - watch this space!

Martin Rhodes G3X20

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particularly suited to the DXenthusiast and could drive theTNC while connected to a DXcluster and be used to provide avery effective logging system(Fig. 3).

Well Designed

The FBS computer system wascertainly well designed and is amuch easier option than tryingto make all the connectionsyourself. As it's supplied withonly the basic software whichgives the buyer the freedom tochoose the best system, Isuspect those that go for thistype of presentation may alsoneed help with the selection ofsoftware.

It may therefore be helpful ifthe manual included a sectionon recommended software. Thedocumentation supplied withthe review model was only indraft form, so I've not been ableto comment on it's quality.

However, a machinedesigned for those unfamiliarwith computing deserves goodquality documentation. Overallthe computer worked very welland provides the basis of a verycomprehensive radio station.

The configuration describedhere is available at the speciallaunch price of £1095excluding VAT from FutureBusiness Systems Ltd.. 21Halford Road, Ettington.Warwickshire CV37 7TH. Tel:(01789) 740073. My thanks toMartin Rhodes G3XZO for theloan of the review model. Alsothanks go to Trio-Kenwood UKLtd.. Kenwood House, DwightRoad, Watford, Herts WD1 8EBfor the loan of the KenwoodTS -850S used in this review.

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_J _J _J LrJ __J _1 JJ.J __J _I _I _I

For many radioamateurs, decidingwhat computer tobuy is one thehardest decisions ofall. Wherever youlook you'll findadvertisers claimingthat their computeris best. With this inmind, the Editorialteam pass on a fewtips to help youmake your choice.

Even if you ask other radioamateurs for advice,you'll soon find thatpeople tend to fall into

camps with equally compelling(and conflicting!) argumentsregarding the best computer. Sowhere do you start?

While it's very easy to getcarried away with the hardwarefeatures of the variouscomputers, the only thing thatreally counts is the softwarethat's available. There's littlepoint in buying a super -fastcomputer if there are noprograms available that do whatyou want!

Over the years there havebeen many computers that have

found favour withamateurs. All ofthese machinestherefore tend tohave good softwaresupport, often with aplentiful supply ofshareware programs.

Examples of thosefalling into good

28

Choosing &Usin

60(Aaret

software support category are:Commodore C64, Atari and theBBCB. So, if you're looking for asecond-hand computer, theseolder machines can be a verygood buy, providing you checkout the software first.

Good places to look for thesoftware are J & P Electronicsand Grosvenor Software, etc.

Moving more up-to-date, thenumber of different computersavailable has diminished. Thefocus is now around the Amiga,Archimedes. Apple Macintosh(Mac) and IBM PC orcompatible.

Desktop PublishingAlthough the Mac is anexcellent computer, here in theUK it's only really taken -off inthe desktop publishing world(PW is produced usingMacintosh machines). As aresult, there's not muchamateur radio software around.

In the United States, thesituation is different as the

Macintosh has a much greaterfollowing there. So, if youdecide on a Macintosh. you willneed to check-out Americansuppliers to find the bestamateur radio software.

The Archimedes, rather likethe Mac. has had limitedmarket success and is largelylimited to educationalestablishments. If your interestlies with weather satellites,contact Spacetech, who offer arange of very good products.

The Amiga is anothercomputer that's received onlylimited acceptance in theamateur radio market althoughit is technically a verycompetent computer. And, bynow you've probably gatheredthat we're homing in on the IBMPC and its clones as the bestchoice for amateur radio use!

Although many would arguethat there are other computersthat are both cheaper and morepowerful, none of these canmatch the PC for software andhardware support. For thatreason we have covered thechoice of PC in a little moreextra detail.

What's A Clone?One of the first questions

facing someone new tocomputers is what's an IBM PCclone? The answer is it's simplya computer that's built with allthe essential features of an IBM

PC so that it can use the samesoftware and accept the sameplug-in expansion cards.

Although the original IBM PCstarted with the market lead inthe desk -top PC, this haschanged over the years. Andnowadays there are a number ofdifferent manufacturers sharingthe PC market.

Another important pointabout most PCs is that they aresimply a collection of parts froman assortment of third partymanufacturers. This mix andmatch approach makes it verydifficult to make comparisonsbetween differentmanufacturers.

When you come to choosingyour first PC there are manypoints you need to appreciate.The first is to note that PCshave been built with a numberof different central processorunits.

As the name implies, thecentral processor is the mainchip or device that controls theoperation of the computer. Andincidentally, the very first IBMPC computers used an Intel8088 chip.

The 8088s were supersededby the 80286, 80386, 80486and currently the Pentiumprocessors. There aresimilarities between all thesedevices, but the later versionsare both faster and morepowerful.

Along with the processordevelopments, the rest of thecomputer has undergoneconsiderable change. Forexample, the video systemshave gone from the old ColourGraphics Adapter (CGA) throughthe Versatile Graphics Array(VGA) to super VGA (SVGA). Ineach case the change hasbrought about higher definition.

One of the problems with thefaster processor is the need tomove data around within thecomputer at higher speeds. Themost important development onthis front is the VESA Local Bus.This provides a connectionsystem that lets peripheral


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systems like the video and harddisk systems talk to theprocessor at around 33MHz asopposed to the 8MHz used byolder systems.

Finally, to help you chooseyour first PC, here are a fewpointers. Although you may betempted to go for a cheap PClike early Amstrad 1640 series,you are advised against it asthese offer very limitedperformance.

You need to start with thefastest processor you can

afford. If you want to operatewith modern Windows basedsoftware you will need at least a386 processor and a minimumof 4Mb of RAM.

If you can afford a 486based machine then make sureyou buy the 486DX rather thanthe slower 486SX. While thePentium chip is the fastestcurrently available, thedifference between a 486 andthe Pentium only really shows ifyour software is specially writtento take advantage of the

Pentium.As there is little or no

amateur software speciallywritten for the 486 or thePentium 586, it's probably notworth spending the extra moneydemanded by a Pentium basedsystem. But, if you're reallyuncertain about choosing a PCfor radio use, you would be welladvised to go for a radio -readyPC such as those supplied byMartin Lynch or Future BusinessSystems.

Data ModesMike RichardsG4WNC providessome advice to helpyou to start usingdata modes,without spending allyour pocket money!

With so many amateurs nowusing computers in the shack.there's an opportunity to utilisethe expensive and powerfulequipment for more than justkeeping the log book. To findout how...just read on!

In this feature I'll attempt toshow you how you can try outthe data modes without firstneeding an overdraft! Thesecret lies in the use of thesoftware distribution systemknown as Shareware.

Shareware is a systemwhere by a version of thesoftware is made freelyavailable to everyone at nocharge. However, althoughsome suppliers provide the fullpackage (but with a time limit).others supply a limited or earlierversion of the software.

With both Sharewaresystems you are expected tomake a voluntary contribution tothe author after the trial period.In return, you'll either receivethe full package or you becomeentitled to a free upgrade.

The Shareware system hasbecome well established in thecomputer world. And I think it'sparticularly appropriate for the


author who wants to make asmall profit on a system that'sessentially been produced forhis or her own use.

In this example, I'veconcentrated on software that'savailable for the IBM PC andcompatible computers. This hasbeen because not only is the PCmore widespread than any othersystem, but the softwaresupport is also verycomprehensive.

For those with other systemsI know this can be veryfrustrating. However, if you havedeveloped your own software fora non -PC system why not usethe shareware system to makeit available to others. If youneed help with this, contact mevia my 'Bits & Bytes' column.

Package To StartPersonally, I think by far thebest software package to startwith is HAMCOMM 3.0 byWilhelm Schroeder DL5YEC.Wilhelm released the firstversion of this program back in1990. but since then it's gonefrom strength to strength.

The latest version ofHAMCOMM 3.0 features manysophisticated extras and cansend and receive c.w.. RTTY andAMTOR. Another good pointabout this particular system isits modest demands on thecomputer hardware.

Although Wilhelm's programcertainly works best with amodern 486 machine, it will stillwork quite comfortably on anold 8086 based system. Youjust lose some of the fancytuning aids!

Contact AddressesBadger Boards.80 Clarence Road.Erdington,Birmingham B23 6AR.Tel: 0121-384 2473

Future Business SystemsLtd..21 Halford Road.Ettington.Warwickshire CV37 7TH.Tel: (01789) 740073.

Grosvenor Software(G4BMK).2 Beacon Close.Seaford Close,East Sussex BN25 2JZ.Tel: (01323) 893378.

J & P Electronics Ltd..Unit 45 Meadowmill Estate.Dixon Street,Kidderminster.Worcestershire DY10 1HH.Tel: (01562) 753893.

Martin Lynch G4HKSThe Amateur RadioExchange Centre.140 -142 Northfield Avenue.Ealing. London. W13 9SB.Tel: 0181-566 1120.

Pervisell Ltd.. 8 Temple End.High Wycombe,Buckinghamshire HP13 5DR.Tel: (01494) 443033.FAX: (01494) 448236.

Spacetech.21 West Wools.Portland, Dorset DT5 2EA.Tel: (01305) 822753

Venus Electronics.26 Pevensey Way.Frimley Green,Camberley.Surrey GU16 5YD.Tel: (01252) 837860.

In addition to the softwareand a suitable computer, you'llalso need a simple interface tolink the computer to yourtransceiver. The full circuitdetails are given in the disk -based manual, but it comprisesa simple Op -Amp limiter toprocess the audio from thereceiver and a low pass filter forthe transmit tones.

The filter is very necessary!It's used to convert the verycoarse square wave output fromthe computer into a low levelsine wave that can be fed intothe microphone socket of yourtransceiver.

The only other electronicsrequired is a simple transistorbuffer. This connects betweenthe computer serial port andthe p.t.t. line of yourtransceiver.

If you would rather buy aready -built interface. BadgerBoards sell a kit at around £25.Alternatively Venus Electronicscan supply a very neat ready -built unit for approximately £50.And should you only want toreceive data modes then theinterface produced by Pervisellis excellent value at just£16.99 ready -built.

J_9121 2_11 JJJJJ

Data Modvit,:4444sote

Software InstalledOnce the software has beeninstalled into a suitable sub -directory on your hard disk(C:\hamcomm) the program andsupporting files occupy just over1Mb of disk space. But beforeyou start using the programseriously it's as well to print-outthe manual using the disk filehc.doc.

The best way to print out isto set your printer font for 12characters per inch and fromthe Hamcomm sub -directorytype COPY HC.DOC LPT1.

Once you have the programrunning and you've taken timeto explore some of its features,take a look at the HC.CFG filewith a simple text editor. Thesample file is very welldocumented and it's anexcellent way to set theprogram up to suit your ownpersonal preferences

As the HAMCOMM 3.0program is so well developedand easy to use it makes a verygood starting point for anyonethinking about experimentingwith the data modes. However,because it's unfamiliar groundfor many people, some havetrouble mastering the tuningtechnique.

The best way to learn thetuning technique is with a goodreliable commercial station. Agood example of this is theBracknell Meteorological RTTYtransmission that's to be foundon 4.489MHz.

To receive the Bracknelltransmission, set the mode toBaudot (F3), speed to 75 baud(C) and keying to 425Hz. Next

set the mode to tuneand adjust yourtransceiver's tuninguntil the flashingwhite squaresstraddle the centrepoint of the display.

If you now pressALT M - Baudot, youshould find groups of

Filo Nods Speed Keying Port Text 0th Info HelpTune -----1Tue Her 14 1995 21:47:09

Slynel frequency 80419Hz

0 580 1000 1588 2000 2500

11111111, i1lii.1,1111

I1 1ll''''Ill11 11111I

0 500 1000 1580 2000 2500

Center frequency 81200Hz

Colouor> <rooet) :higher+,

FleNtelp> (FIB.Monu> <OLT. .Command> <ALT+X.Exit) HamComm 3.0 by DLSYEC

HAMCOMM tuning Indicator.

five figure numbers beingdisplayed on the screen. If youwant to turn this into somethingmore interesting you canactivate HAMCOMM's SYNOPdecoder.

All you do is select the textmenu and select FORCE SHIP orFORCE SYNOP. You'll then bepresented with plain texttranslations of the codedweather data.

Having completed somereceive practice you only needto set your transmit power leveland you're ready to starttransmitting. However, beforeyou do Please spend some timelistening to familiarise yourselfwith the operating practice.

FAX And SSTVIf you're now 'hooked' by thefascinating aspects ofcomputing in amateur radio,you're probably ready to moveinto the more complex modes ofFAX and SSTV. Fortunately, thisis actually very easy, thanks tothe hard work and dedication ofthe shareware authors.

In this particular case I'llconcentrate on the JVFAX 7.0

program written by EberhardBackeshoff. This verycomprehensive program usesthe same interface as Idescribed earlier for HAMCOMMand provides facilities for thesending and reception of bothFAX and SSTV signals.

As you might expect fromthese highly graphical modes,JVFAX makes much higherdemands on the computerhardware. Especially so if you'reusing the simple interface.

For best performance you'llneed at least an IBM PC orcompatible computer with a 386or better processor, 4Mb RAMand a SVGA display. Theprogram has been designed tosupport most modern videosystems and includes drivers forVESA based systems.

If you want to use theprogram with a slower machineyou will have to compromise theperformance by reducing thehorizontal resolution.

An alternative is to obtainone of the complex interfacessuch as that produced byMartelec. These units have theirown processor built-in thatrelieves the processing load onthe main computer.

Installation of JVFAX is verysimple. This is because the set-up program (INSJV70)automatically unpacks all theprogram and support files andcreates the appropriate sub -directories.

In addition to providingsupport for the amateur FAXmodes, JVFAX includes facilitiesfor all common types of I.f., h.f.and satellite FAX systems.

Included in this armoury is fullyautomatic reception of APTweather images.

Now it's time to look at TV -slowly! Slow Scan Television(SSTV) remains a populartransmission system for manyamateurs and can usually befound on the 14MHz band ataround 14.215MHz.

The JVFAX program isequipped with just about everySSTV mode including themodern colour systems. Theprogram is extremely easy touse and includes facilities forsuperimposing your callsign onthe transmitted image.

Packet RadioPacket radio is one of theliveliest of the data modes andas such attracts a lot ofinterest. There are various waysto get started, but if you'reusing a PC you might like to trya receive only system just tosee what goes on.

Like the other programs inthis section. PKTMON12 isshareware and is readilyavailable from most goodshareware suppliers. Althoughthe program is very compactand basic, it demands a lot ofprocessor time, so you'll need a386 or better processor in yourPC.

The user interface toPKTMON12 is rather crude andcan confuse new users so I'llquickly run through it here.When you start the program youwill be asked to select a COMport which can be either COM 1or 2.

Next, you need to choose toreceive h.f. or v.h.f. packet, thedifference is 300 baud 200Hzshift on h.f. and 1200baud1000Hz on v.h.f. You also needto provide a file name for thereceived data.

Instead of displaying all thereceived data just to the screen.PKTMON logs all the data to aseparate file for eachconnection it identifies. Onceyou've started the program, youjust leave it to gather all thecurrent QS0s on that frequency.

At the end of the monitoringperiod you just press enter tofinish the session. You then usea simple text editor such asMSDOS EDIT to look throughthe received files. Clearly, thissystem is only really suitable for


JJJJJJJJJ 2_11 11 LLI

An SSTV picture received by G4WNC while using NFAX.

those that want to take a lookat the mode with minimum cashoutlay.

Another less obvious benefitof PKTMON is that is has beenwritten in Turbo Pascal with allthe source code supplied. Thisis very useful for those whowould like to write their ownsoftware as all the basicroutines for converting audio todigital are ready -built.

Terminal NodeControllerIf you're more seriouslyinterested in Packet radio thenyou need to get yourself aTerminal Node Controller (TNC).A TNC is a processor controlledinterface that handles theconversion of simple text to andfrom the computer into audiosignals to link with yourtransceiver.

As you would expect, it alsoprovides all the control facilitiesto link with the Packet network.Fortunately, one of the

advantages to come from thepopularity of packet radio is aplentiful supply of second-handTNCs.

The TNC can be used withthe simplest of communicationsprograms. Despite this, adedicated packet driver makesthe system much easier to use.

If you're a PC user runningWindows 3.1, one of the bestprograms around at the momentis UltraPak 2.0 by Tim KearsleyG4WFT. A demo version of thisimpressive software is currentlybeing distributed as sharewareso it's a great way to start onPacket.

The only difference betweenthe shareware and full versionis a 30 minute continuoususage limit. You can, of course,start the program again foranother 30 minute session.

The program is supplied on a1.44Mb floppy disk andincludes a complete installationroutine. This moves all the filesto their correct directories onyour hard drive and creates theusual program group and

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The UltraPak main logging screen.


associated icons.The Windows screen layout

is really good. It has beenarranged to give the operatorrapid access to all theprogram's facilities.

One aspect that was handledparticularly well was the facilityto shell out to otherapplications. Included here werethree push buttons set up sothat a single press took youstraight to print manager,program manager or a basicDOS shell.

UltraPak version 2 also

Shareware Reminder

includes full support for multipleconnects with the data for eachconnect confined to its ownwindow. You can even select asplit screen display so you canview two connections at thesame time.

At present, UltraPak isconfigured to work with TNC-2type TNCs but Tim has reportedthat he's currently working toextend the compatibility to workwith other systems. He's alsoworking on a script languageand PMS facility.

Now for a Shareware reminder! For many people the cost ofmodern commercial software can be a deterrent to even startingdown the road of home computing.

The solution for most is to take advantage of the wide rangeof 'free' programs that are readily available. For the radioamateur this is a particularly good option as there's plenty ofvery good quality software available for most radio relatedapplications.

The software is usually distributed in one of two basic formatsshareware or freeware. Shareware is by far the most common,but sadly often abused.

The whole principle of shareware operates on the basis oftrust. The program author releases the program onto the marketplace, but asks the user to pay a nominal sum to the author ifyou find the program useful. While some authors give theprogram a mild handicap such as a delayed start-up with ashareware prompt, others release the software with nooperational restrictions.

The typical registration fee requested by most authors isaround £20 to £30. In exchange for this payment you willnormally receive a full version of the program and some form ofsupport.

Another important condition about shareware programs is thatall the files must be distributed without alteration. If you want tocopy the program to friends this is usually acceptable practice,but check the conditions before you do.

The sad fact about shareware is that very few people actuallybother to register with the author. Not only does registration giveyou access to support but it gives the author someencouragement to develop the program further. So pleaseregister your shareware.

Finally, a quick word about Freeware. This operates invirtually the same way as shareware except there's noregistration fee to be paid.

There's a whole new world of computing in radio foryou to explore. So, why don't you join me every monthin 'Bits & Bytes' - The Computer In Your Shack? Don'tforget you can write to me at anytime and I'll bepleased to hear from you.

pS,M,C, & RIG WARD

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press the letter 'P' whenviewing the main menu(pressing 'S' stops thisaction). Should yourprinter not be connectedor isn't 'on line' then theprogramme willautomatically indicatethis on screen.

Using A HardDiskThe program can becopied onto thecomputer's 'Hard Disk'(Drive 'C'). At the end ofthe 'Transmitting Period',the data must betransferred to a floppydisk. It should beremembered that thefloppy disk used mustonly contain the logbookdata.

Editorial Note: If youwould like a copy of thePW Logbook -95, writedirect to John Beaumontat 28 Barton Road,Davyhulme, Urmston,Manchester M41 7WAenclosing payment of £6with your request. Anddon't forget your addressof course!

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John Beaumont G3NGD has written a basiccomputer logbook program especially forreaders of PW, which he describes here.

0n purchasing a newcomputer, I decided towrite a simpledatabase program to

be my logbook. The object ofthe exercise was to enable meto speedily identify if I'dpreviously worked the station.The Amateur Radio LicenceTerms. Provisions andLimitations Booklet BR68states that a log should bewritten in a book or may bekept on a computer disk ortape.

All records shall be kept forinspection by a personauthorised by the Secretary ofState for at least six monthsfrom the date of the last entry.Furthermore, the tape or diskmust only be used to keep thelog on.

For speed of operation,both the program and datafiles are kept on a hard disk.But you must remember tocopy the data file(s) to floppydisk at the end of the session.

Design IdeasWhen operating on repeaters,many operators don't wantsignal reports, so I omittedthese columns. You can alwaysinclude signal reports in thecomments column anyway.

You can print out a logbook,or sections of a logbook ontopaper. There is also a meansof correcting data errors savedon the disk. But to meet theregulations, it's not possible toinsert entries at a later date.

The time and date must beset correctly before you start,(don't forget to set thecomputer clock to GMT/UTC).

A clock with date isdisplayed, in real time, on thescreen. This will enable you toenter the correct time.

A complete entry is only 80characters (one screen line),so many entries can be storedon even a low density disk.

In ActionLet's look at the program inaction. When the opening titleappears on the screen, youmay open a new file. This will


always be the case when theprogram is initially used.

In normal use, the file ofdata is updated only, so caremust be taken to ensure thatthe new file option is notselected.

To ensure that an originalfile is not erased when creatinga new data file, a warning isgiven. Then before possibledestruction of data, a finalreminder is given. You shouldmake a backup copy of thelogbook data/disk after eachsession, in case of datacorruption at a later time.

Logbook UpdateFrom the main menu, thelogbook can be updated. Thefrequency band entry must notcontain more than threenumbers.

The remarks column maycontain any information, but islimited to a maximum of 35characters.

Each contact is given aunique record number, and thisrecord number is used toidentify the section of data tobe edited. The data isamended like the original entrymethod.

A search can be made forany data contained in theremarks column. Callsignsearches can be made evenrequesting, for example, /P, or/MM stations.

You can make frequencyband searches for contacts.The program lists all contactsrecorded on a particular band,e.g. 1.8, 3.5, 144MHz. Note:That if 14MHz is requested, itshould be entered as 14<space> RETURN, or 144MHzwill be printed. (The search canbe made on any particularsingle number).

You can list all the contactsmade in any particular year. Forinstance, enter '94' for 1994('92' for 1992, etc.). Note:Pressing the pause key willstop the screen scrolling. Thiscan be cancelled by pressingthe ENTER key.

If a printer is available, thenthe lists may be sent to theprinter. To initiate this facility

"11'21-201A-21Iljj-21 JJ .21-a1-21-_,IsJ

AmateurR9019Mike Richards G4WNC casts his experienced eyefar and wide to gather all the up-to-dateinformation on the latest computer associated event to attract attention - the Internet -from the amateur radio viewpoint. Mike then rounds off with a look at CompuServe.

170 LIM YliNJ (in 13g)06Innrk, OptIo4, Dire. loryWelcome To Ihe Amateur Radio WO Server

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Welcome to the World of Internet AmateurRadio

Am:

%Vei....sr. Youre inunber 8211 01 thr people u1.ive \13rcit I I. . . .

Anyone with even apassing interest incommunications orcomputing can hardly

have missed the enormoushype associated with themedia's discovery of theInternet!

I say discovery because youcould be forgiven for mistakenlythinking the Internet is a newproduct that's just beenlaunched. If so you'd be wrongon two counts as it's neithernew or a product that you canbuy! So just what is it?

In reality, the Internet is justa collection of computersystems and networks that havebeen connected together. Themost significant point is that nosingle body either owns orcontrols the Internet.

The interconnectionsbetween the computer systemsare provided on an individualbasis. This is done without anyconsideration for the overallnetwork.

I shan't bore you with lots ofhistory, but one of the maindriving forces behind the

creation of the Internet hasalways been the

educational andresearchestablishments.They have a need tocommunicate withother academicsaround the worldand have developed

the Internet to provide thatservice.

The provision of linksbetween these establishmentsformed the start of the Internetas we know it. This process ofgradually interconnectingcomputer networks hascontinued over many years andthe present Internet providesaccess to thousands ofnetworks with an estimated 30million users.

Because nobody owns orcontrols the Internet, it'simpossible to be precise aboutits real size. That's enoughhistory so, let's now see howyou get connected and what's init for the radio amateur.

Needs And BudgetNot surprisingly there are lots ofways to get connected to theInternet...depending on yourneeds and budget. If you're auniversity student you may wellbe able to get connected simplyby using the university's owncampus network.

With the popularity of Packetradio you may be wondering ifthere's a packet gateway youcan use. And unfortunately,there are a couple of problemsthat currently make thisimpractical.

The first is the regulatoryissue regarding the handling ofinformation from unlicensedsources. Although it would be

comparatively easy to provide alink between the packet networkand the Internet, there's noeasy way to ensure that onlymessages and traffic fromlicensed amateurs escape fromthe Internet into the packetnetwork.

The other limitation is that ofdata throughput. Whilst mostamateur links operate at1200baud, many Internetfacilities require 9600baud asan absolute minimum with14400baud being the acceptedstandard. If you think about thebaud rate in terms ofdownloading, some simplemathematics soon puts thedata throughput problem intoperspective.

Most of the softwarearchives on the Internet storetheir data in compressed format(usually 'zip' format for PCs).Even with this compression,files are often 300k bytes plusin size. This means that some(300,000 x 8) 2,400,000 databits need to be sent to -

complete the transaction.At a constant 1200 bits/s

this would give a transfer timeof 33 minutes. However, thisfigure makes no allowance forthe error correction processwhich divides the informationinto packets withacknowledgements sent aftereach packet to confirmreception. This would reducethe throughput by around 25%so increasing the transfer timeto about 41 minutes.

However, you would only seethis level of performance if youhad exclusive use of the linkfrom your computer through tothe distant host and yousuffered no interference hits.As this rarely happens you canexpect further slowing of thetransfer due to wait periods andrepeated packets.

The end result would

probably give a transfer timecloser to an hour for the 300kprogram. If very many peoplewere doing this you can seethat the system would quicklygrind to a halt!

For most people then theonly practical way to join theInternet is via a modem anddial -up line. This will connectyou to what's become a growthindustry - the service provider.

Service ProviderThere are a host of companiesacross the land that offer theservice provider function. Theycan be divided into two maincategories - bulletin boardaccess (BBS) or full InternetProtocol (IP) connection.

While the BBS connection isusually the cheapest option, thedown side is limited access tothe Internet's range of facilities.But before I go into some detailon how to choose a serviceprovider, let's take a look atsome of the available servicesand how they can be used bythe amateur.

Universally UsedProbably the most universallyused Internet feature is that ofElectronic mail or E-mail This isa very fast and effective way ofcommunicating globally.

If you join a service providerwith just BBS access you willoften find that E-mail is the onlyaccess you have to the Internet.When you connect to theInternet, your service providerwill allocate you an E-mailaddress which is exclusive toyou.

There are a number ofdifferent formats for theaddress for E-mail. So, I'll usemine as an example:[email protected] the first part is


S121 ,A111111 .2J4 .sJ JJ JJJJJ

tk Sochtlyd IVO~ Nana Aalrernwrars,,

'the Societe of Amateur Radio Astronomers (SARA)

The &very of .v114r.o N t S.'.RA) 1. 4 d4dIC4.4d grn.4' .fP4C4,14rowed an Ine Ertl/1101.1 I et, 11 Iron tr,k ttChrieLal tIktolnmtion end AI.. theiroN.N

exclusive to me whilst the @points to the domain I'm usingwhich in this case is the BBCNetworking Club (bbcnc).

The next part shows that theservice is provided by anOrganisation (org). The finalsection the country of origin(uk).

An alternative examplewould be my CompuServeaddress which is100411,[email protected]

The breakdown here is thesame as before except that thecorn suffix indicates that theservice provider or domain is acompany.

You'll also note that there isno country identifier. This isbecause CompuServe is a USbased company and, as theyinvented the Internet, they claimthe right not to use a countrysuffix!

In addition to providing thefacility for sending simplemessages, most E-mailapplications allow data files tobe attached to messages.There are a number of ways ofdoing this but one of the mostpopular is called UUENCODING.

In the UUENCODING systemthe file to be sent is convertedinto ASCII characters. This is soit can be transported in thesame way as message text. Atthe distant end a decodingprogram reverses the process.

In addition, E-mail can alsobe used to subscribe to mailinglists. Mailing lists are availablefor a very wide range ofsubjects and one goodparticularly good service foramateurs is that provided by theAmerican Radio Relay League(ARRL).

To subscribe to the ARRL listall you do is send an E-mailmessage to [email protected] withthe word help in the main textof the message. Once joined,you will automatically be sentcopies of all the informationpassing through the mailing list.

It's also possible to use E-mail to retrieve files fromremote computers. But the

All aspects of Amateur Radioare available on the Internet.

Screen grab showingCompuServe's HamNet

forum.

process tends to be rathercumbersome and slow.

Usenet GroupIf you have a full IP connection abetter way of receivinginformation from specialinterest groups is to join theappropriate Usenet group. Thereare literally thousands of thesearound covering just aboutevery subject you can imagine.

In order to access thesegroups you will also need aspecial newsreader program foryour computer. However, thisshouldn't be a problem as mostservice providers include arange of suitable software whenyou join -up.

If you have the choice youshould use what's known as anoff-line reader. This willautomatically download all theunread news items and storethem on your hard disk so youcan read them after you'vehung -up the phone connection.

Amateur interests areserved by the following popularUsenet groups:

rec.radio.amateur.antennarec.radio.amateur.digital.miscrec.radio.amateur.equipmentrec.radio.amateur.homebrewrec.radio.amateur.miscrec.radio.amateur.packetrec.radio.amateur.policyrec.radio.amateur.spaceuk.radio.amateur

Abundance OfSharewareOne of the great things aboutthe Internet is the abundance ofgood quality shareware or freesoftware for a wide range ofcomputer systems.

You'll find excellent supportfor IBM PCs, Macintosh, UNIX,Archimedes and Amigamachines. The most commonway to acquire the software isto use the Internet's FileTransfer Protocol or ftp.

By far the best method touse the ftp is via what's known

oriliE7rErila7 mrA

HamNet <Ham Radio>+ Forum

Last amt.: COM% 7711

sr

FRrnrgarFlr

as a client program. This is asoftware package that providesan easy to use interface to,what can be, a clumsycommand line method oftransferring files.

With most client programsyou can select the destinationsite and transfer the files simplyby using the mouse pointer.

Favourite ftp sites foramateurs are:

ftp.ucsd.eduftp.cs.buffalo.edu/pub/harn-radioftp.wustl.edu/pub/hamradio

Search SystemThe vast size and rapidlychanging nature of the Internetmeans that you will inevitablyhave to use some form ofsearch system to find what youwant. Fortunately, most of theftp sites use a standard systemfor arranging their sub -directories so you can find mostthings using a simple manualsearch.

By way of an example,Windows software will normallybe found in the directory pathpub/ibm/windows. If you doneed to use an automatedsearch one of the most popularand easiest to use is calledArchie and is available at anumber of key sites across theInternet.

The principle of Archieoperation is very simple. Itrelies on the Archie serversholding a database of the filesavailable across a wide range ofsites.

By using Archie clientsoftware you can search thedatabase to find the file youwant and then automaticallytransfer the file to yourcomputer. Although a long wayfrom being perfect, it doesseem to be an effective way tofind files.

World Wide WebNow if you really want to

impress your friends, the WorldWide Web is the service for you!The WWW is the user friendlyface of the Internet and I'msure it represents the wayforward.

The WWW system useshypertext links and extensivegraphics to create a simple touse yet very powerful way tonavigate the Internet. There area number of client programsavailable, but for PC users thebest by far is Netscape v1.0(available from most ftp sites inthe www section).

The Netscape has beendesigned specifically to operatewith dial -up links and isoptimised for use with 14.4kmodems. Not only can theprogram display all the graphicsand make best use of thesystem but it will handle Usenetnews, mail and file transfers.

One of the best startingpoints for UK amateurs ishttp://www.mcc.ac.uk/OtherPages/AmateurRadio.html. If youwant to just 'surf' the Net,another good starter ishttp:/akebono.stanford.edu/yahoo/

Get ConnectedHaving whetted your appetite I'lltry to give you some guidanceon how best to get connected. Ifyou're happy with just E-mailaccess your best bet is to useone of the many serviceproviders that give just BBSaccess as this is by far thecheapest.

It's as well to make surethat the provider you choose isas close as possible to yourhome and preferable with thelocal call charge area. This willkeep your telephone bill undercontrol!

If you need to buy a newmodem I would stronglyrecommend getting the fastestyou can afford. The best valueat the moment lies with 14.4kbmodems, though no doubt28.8kb units will be dropping inprice soon.


.FAA'211.21

Amateur RadioIf you're going for full IP

access you again need to picksomeone close to home anduse the fastest modem you can.If you want to use WWW ortransfer a lot of files, a 14.4kbmodem should be consideredthe absolute minimum.

When you start looking atservice providers you will seethat they operate Points ofPresence or PoPs locatedaround the country. The PoPsare just dial -up nodes that arespread around the country tohelp minimise telephonecharges.

Ideally you should choose asupplier with a PoP within yourlocal call area. This is because(as you'll find!) that of all thecosts of getting on the Internet.telephone charges take thelions share.

Of the suppliers I have used,I found Demon to be thecheapest (£10 a month), butwith some network congestiondue to their fast growth rate.

The Pipex Solo network (£15a month) has by far the bestinterface software and offersexcellent data transfer ratesand reliable access.

After sampling several full IPsuppliers, my final choice has

,i7 l'Acterocebeen to go for the BBCNetworking Club which at £12per month offers reasonablecosts plus excellent access andtransfer rates through their useof the Pipex network.

As an added bonus, the £25start-up fee includes a full setof software. There's alsoprinted manual and access tothe BBC's Auntie Bulletin Boardsystem.

CompuServe forAmateursWhilst you can hardly open amagazine without somereference to the Internet thereare alternative networks aroundthat can offer the amateur a lotof support. One of the bestestablished of these is theAmerican CompuServe network.

Although CompuServe'sorigins lay firmly in the USA,they have extensive links toEurope and in particular the UK.The system is basically a verylarge bulletin board network.

CompuServe's attraction liesin its acceptance by industry asan effective electroniccommunications supplier. Justto take the E-mail facilities asan example. CompuServe have

interfaces to a number ofexternal communicationssystems and you can use the E-mail system to send a FAX toany FAX machine world-wide.

All you have to do is insertFAX: followed by the telephonenumber in place of the E-mailaddress. For the amateur one ofthe main reasons forconsidering joining CompuServeis the extensive product supportthat's available.

All the major hardware andsoftware houses have their ownforums on CompuServe. Youcan join these for technicalsupport or maybe to get thelatest software drivers or fixfiles.

For dedicated amateursupport there is a specialistHamNet forum. This specialarea of CompuServe is packedwith software and advice for allaspects of our hobby. It's in thissection that you will find all thesatellite orbital data plus all thelatest news and views.

You can also join on-linechats with other amateurs. Forthose of you already involvedwith data modes there's even adedicated section for AEAproducts such as the PK-232.

Having used this system for

some time, I think there's nodoubt it's one of the mosteffective and reliable ways toget up-to-date information.However, if you can't decidebetween CompuServe and theInternet you'll be pleased tohear that CompuServe have anInternet gateway that enablesyou to send e-mail, join Usenetgroups and download software.

The other important point isthat the CompuServe network isextremely easy to use. This isthanks to their excellentInformation Manager softwarethat's supplied as part of thestart- up kit.

With this software you cannavigate your way around all thefacilities at the stroke of a key(or mouse). In addition to thesoftware all you need is asuitable modem that can befrom 2400 baud to 14.4kb.

CompuServe's pricingstructure has recently beensimplified and you can expect topay around £6.50 per monthsubscription plus up to £3.14per hour for downloads. Formore information onCompuServe just contact theirSales line on (0800) 289378.

PW

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111'21A1I1j1IJA'SJ

Jim Butler GM3ZMA shows you how to get a computer to do all the hard work,calculating potentiometer ratios.

Given the input voltageand the required outputvoltage, it is well knownhow to calculate the

values of resistors to use in asimple voltage divider network,such as the one shown in Fig.1. First, select a value for R2and then calculate the value ofR1 using the equation:

V.R I] R21` '

out

It's quite straightforward so far,but what value do you select forR2? It would be very nice if youcould select a preferred value forR2, do the calculations and endup with a preferred value for R1.

But in practice, you usuallyfind that Ri turns out to be avery odd value indeed. Yes, youcan always make it up from twoor more preferred values,however, it would be much nicerif you could use preferred valueresistors for R1 and R2. Thefollowing computer programmehelps you to do just that.

The ProgramThe program was written in Basicto run on a BBC 'B'microcomputer. I've kept theprogram to a bare minimum,avoiding the use of featuressuch as screen formatting whichwould be particular to BBCBasic. This means that theprogramme may be easilymodified to other dialects ofBasic used by any of the otherpopular home computers.

The program operates asfollows: Lines 30 and 40 promptfor the input and output voltages.Lines 70 to 110 form a loopwhich reads the value forresistor R2 from the data

fl

Flg. 1: Such a simple circuit,but that doesn't meanfinding the correct values ofR1 and R2 is easy!


statement in line 180, calculatesthe corresponding value for R1(held in the Data statements inline 90) and then displays onscreen the values of R1 and R2(line 100).

The loop is run 12 times forthe step values of the E12series of resistors. The programthen prompts and waits for a keyto be pressed (lines 130 and140), before repeating thecalculation using the 12 extravalues of the E24 series ofresistors, (line 190). Lines 20.120 and 150 ensure that theprogramme ends after the E24series calculation.

Input VoltageOn running the program you willbe asked for the input voltage tothe divider, and the desiredoutput voltage. After these havebeen entered, the computer willprint the two columns of values,R2 on the left and R1 on theright.

You must now visually inspectthe right hand column for a valuewhich is suitably close to apreferred value for the desiredapplication. If no preferredvalues are seen, press any keyand a new set of values will bedisplayed, again, visually inspectfor a preferred value in the righthand column.

If none are found, then onemust revert to using tworesistors to make up therequired value. All that remainsto be done now is to scale theresistor values to an appropriatedecade.

An Example

As always an example is worth athousand words. So let'ssuppose you have a 12V supplyand require 7.5V. After runningthe programme you see thatsuitable values are 3.36 for R1and 5.6 for R2.

If the current drain from thedivider output is low, say 1mA,the real values would be 3300for R1 and 5600 for R2. Thiswould give a standing current inthe divider resistors ofapproximately 13mA, which issufficiently large to swamp anyvoltage pulling effects due tochanges in the output current.

Preferred ValuesLike most analogue things,resistors are rarely of the exactpreferred values with whichthey're marked. How close aresistor will be to its nominalvalue will depend on thetolerance of how much errorwas allowed in the selection ofthe resistor during manufacture.Also, resistor values will varywith temperature and age. Italso depends on the materialfrom which the resistor is made.

So, when you buy say a100f/ resistor with a toleranceon 10%, the actual value maybe anywhere between 90 and1100. Similarly, a 1000resistor with a 5% tolerancemay be between 95 and 1050.

To save producing an infinitenumber of resistor values withvery close tolerance whichwould make them veryexpensive, manufacturersproduce resistors in series ofpredefined values. Thus for 10%tolerance resistors, the 'E12'series is used, and each valuein the series is 1.2 times(approx) the value of itspredecessor. The 12 in E12comes from the fact that thereare 12 values in each decade.

So, the step values for theE12 series are: 1.0, 1.2, 1.5,1.8, 2.2, 2.7, 3.3, 3.9, 4.7,5.6, 6.8 and 8.2. These stepshold true for all decade ranges,i.e. 10 to 820, 100 to 82012,1000 to 82005, etc.

When closer tolerancevalues (5%) are required, thegaps in the series are filled inby additional values in the so-called the E24 series. In thisrange each larger value is 1.1.times the value of itspredecessor.

In addition to the all the stepvalues of the E12 range, theE24 series also includes the

following values: 1.1, 1.3, 1.6.2.0. 2.4, 3.0, 3.6, 4.3. 5.1,6.2, 7.5 and 9.1.

The ComputerI realise that not everyone willbe using the same computer asI use. So, for those of you notusing BBC Basic, and I supposethat means most PC users, thevariables (VIN, VOUT and FLAG)can be reduced to only the firsttwo characters.

So now you know how to getthe computer to take the strain,there's no reason not to getcalculating those potentiomete'values. Pw

10 CLS20 FUW = 030 INPUT 'Divider input volts', VIN40 INPUT 'Divider output volts',

VOUT50 PRINT 'E12 SERIES'60 PRINT 'R2. R1'70 FOR N = 1 -1280 READ R290 R1=(VIN/VOUT -1)*R2100 PRINT R2. Ftl110 NEXT120 IF FLAG>0 THEN END130 PRINT 'PRESS ANY KEY FOR

E24 SERIES'140 DELAY = GET150 FLAG = 1160 PRINT 'E24 SERIES'170 GOTO 60180 DATA 1.0, 1.2. 1.5, 1.8, 2.2.

2.7. 3.3. 3.9, 4.6, 5.6. 6.8.8.2: REM E12 SERIES

190 DATA 1.1. 1.3, 1.6, 2.0, 2.4,3.0. 3.6, 4.3, 5.1, 6.2. 7.5.9.1: REM E24 SERIES

Listing: This is thesimple program todo all the hardwork. Make it asfancy as you wish ifyou find it useful.

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AVAAPTINI iL1/21CHSAM WARIRAN I

THEORY

Around The LoopRichard Q. Marris G2BZQ discusses variants of the loop antenna

Loop antennas are with us in manyforms and variations of those forms.They produce a certain amount ofconfusion!

The fact is that a loop antenna is one, ormore, turns of wire (or tubing) which resonates,or is resonated, to a required frequency in thev.l.f., II., m.f., v.h.f. and u.h.f. bands.Furthermore, with correct design, the loop,irrespective of type, can be matched into themodern communications receiver and loaded, inmany cases with a transmitter. Loop antennasare bi-directional.

Loops also appear in several basic types, andeach type incorporates many variations. Thistherefore adds to the apparent confusion.

Basic Full Wave

The basic full wave, or quad, loop has acircumference equal to one wavelength (or amultiple) at one frequency. Because on h.f. theremay be large dimensions involved, this loop ismore usually considered ideal for u.h.f., v.h.f.and the higher h.f. bands. Those lucky amateurswith a large area of real estate, can use them on7 and 3.5MHz or even 1.8MHz.

The basic configuration of a quad loop isshown in Fig. 1. Here you will see that if theloop is split, and fed with a transmission line(not just coaxial feed). In this way it can be usedfor both transmission and reception at theresonant frequency.

Although Fig. 1 shows the square full -waveloop, it may be built in rectangular, triangular(then called a delta loop), diamond and othershapes. The loop can be mounted vertically,horizontally or even sloping, because of itsversatility. The quad loop is well documented inthe many antenna books.

Half -Wave Loop

1 he next smaller version I'll consider is the half -wave loop antenna. This antenna has acircumference equal to a half -wavelength. It canalso be mounted horizontally or vertically.

The loop may he fed ac shown in Fig. 2.

with a coaxial feedline, although a balancedfeed would be better. An insulator placeddiametrically opposite, holds the loop in tension.

The operation of the half wave loop is similarto a dipole. And there are those who contendthat it's not a loop, but a dipole folded back untilthe ends nearly meet.

Whatever the action of the half waveantenna - it looks like a loop! As with the full -wave loop antenna, half -wave loops may becircular, square, rectangular and diamond inshape, as long as they are symmetrical.

Good results have been achieved with thehalf wave loop antenna on 144MHz, usingtubing for the conductor. An excellent 144MHzdesign has been described by F. C. JuddG2BCXt.

Small HF Loop

The small h.f. loop antenna is often used forreception on the lower h.f. bands, e.g. 3.5 and1.8MHz. It may be built in both the screenedand unscreened style. With care, and ingenuity,it's possible to load a transmitter into it, giving acompact table -top antenna.

The diagram Fig. 3 shows the basic small h.f.loop. The circumference of the outer, tuned loopcan be between 0.1 and 0.3% of a wavelength.It can be made with one, or more turns andbrought to resonance with a variable capacitor.

The physical signal null on this type of loopantenna is quite sharply defined, and this helpsin QRM reduction. It also makes a convenientform of a small size indoor receiving antenna.

Look now at the drawing of Fig. 4, whichshows a screened loop antenna. This type ofantenna is often used on the low frequencyamateur bands. It's made of a circle of coaxialfeedline (or tubing), resonated with a variablecapacitor, with the outer braid screening split atthe top, as shown.

The outer braiding acts an electrostaticscreen. It can be between 0.1 and 0.3%wavelength long in circumference. It is highlydirectional with excellent nulling to reduceQRM and the shielding reduces/eliminatesQRN.

Various coupling methods can be used - the

simplest being shown in here. This type of loopis only really suitable for receiver use.

Medium Wave

Physically small loops are often used by mediumwave DXers because of their excellent anti-QRMnulling capability. These small loop antennasnormally consist of a number of turns of wire,wound on a frame, or box, about a metre square(40in x 401n). This winding is normallyresonated to the receive frequency with avariable capacitor.

A single low impedance coupling turn isadded to enable attachment to the receiver'sinput. Many articles have been written aboutm.w. loops, but one of the best, and clearest, isby Charles Molloy G8BUS.

The G8BUS m.w. loops were described inhis article in PVV back in November 1979. Therehave been designs without the coupling coil.The coil is replaced by directly coupling theloop to an f.e.t. or transistor pre -amplifier. Somearticles have appeared in our sister publicationShort Wave Magazine over the past few years.

Long Wave

It's possible to use loop antennas on long wave,and these antennas are ideal for those interestedin long wave DX reception. Few designs haveappeared in print. But one method oftensuggested is to take a m.w. loop, as above, andinsert a 3 or 4mH r.f. choke in series with thewinding.

Insertion of a choke does work, but it's notefficient enough for real I.w. DX reception. I'vedesigned and made several I.w. loops. It's aformidable task, involving winding three to fourtimes as much wire, as for a m.w. loop.

Tests I've carried out, have indicated that aspiral loop gives better nulling and sensitivitythan a box type loop. My best design achievedhas been written up under the title 'The LongWaver'.

I hope this article has given you a thirst to getout and try a loop antenna on your band ofinterest, whatever it is. So get looping! P1N

Fig. 1: The basic fullwave loop antenna.Note the completeconnection.

44

5012

44

Fig. 2: A smaller half -wave loop antenna. Isthis really a folded 1/2dipole?

8

A8

Fig. 3: A physically smallloop with an inductivelycoupled tuning loop.

r Fig. 4: Ashieldedsmall tunedloop antenna.


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CONSTRUCTION

_77y i7Jr FottuThe PW Martlet 70MHzFM Transceiver Part 3

As I've already mentioned, Idesigned the PIN Martlet with asynthesiser to get away from the,,,Kmal 'rock bound' crystaluntrolled approach normally

adopted for simple (usually surplus p.m.r.)rigs. And I chose the diode matrix systembecause it's a cheaper and simpler approachto programming a synthesiser than anEPROM.

To help, I'll describe what goes on in thesynthesiser, starting off with the divisiontechniques used. The programmable divider inthe MC145152 has internal pull-up resistorsbuilt in to all the programming lines, i.e. if noaction is taken, all the lines will be at logic 1.

Divide Ratio

working out the divide ratio. The select lineson the 145152 i.c. are arranged to give thefollowing frequency steps:

AO 6.25kHz NO 250kHzAl 12.5kHz N1 500kHzA2 25kHz N2 1MHzA3 50kHz N3 2MHzA4 100kHz N4 4MHzA5 200kHz N5 8MHz

N6 16MHzN7 32MHzN8 64MHzN9 128MHz

And, as one example is worth a thousandwords, let's now work out the two synthesisernumerical codes for the transmit and receivefrequencies for operation on 70.25MHz. Forthis you need two codes because there are twofrequencies to create - the direct transmitfrequency at 70.250MHz, and the localoscillator (10.7MHz above) at 80.95MHz.

In the table I've provided you will see wehave N values, i.e. NO - N9, as well as Avalues AO - A5. Coupled to these values arevarious frequencies associated with eachvalue. So N3 has 2MHz associated with it. TheA2 value has 25kHz alongside it and so on.

Technique Used

The technique used is to start at the biggeststep end of the table of frequency codes. Youthen successively subtract an 'N' frequency

In part three of his 70MHz QRP fm. transceiver project MikeRowe G8JVE describes the diode matrix programming systemused, and provides the main p.c.b. designs and associatedcomponent overlays.

(then 'A' frequencies) to leave a remainder of 0(zero) or a positive value at each step.

To begin, you take the actual frequencyyou are to create (say 70.25MHz) and carryout an easy series of steps. These steps arelogically the same each time, but just usingdifferent numbers.

Beginning from N9, you compare an Nfrequency with the desired frequency. And, ifthe N frequency is greater than the desiredfrequency, you write down a logical 0 againstthe N value. You then take the next lower Nvalue's frequency and continue with the

If however, the N frequency is smaller, orthe same as the desired frequency thensubtract the N frequency from the desired oneand write down a logic 1 against the N value.The resulting frequency difference between thedesired and the N frequency becomes the newdesired frequency.

It may seem pretty complicated but in thefollowing description I'll call the frequency tobe compared - Fl. So, at the start Fl is the fullfrequency of 70.25MHz.

Step one is to take the biggest N frequencyfrom the table, that's smaller than F1. So, N9'sassociated frequency of 128MHz is too big.But N8's frequency, at 64MHz is smaller thanFl. This means N9 is a logical 0, N8 is activeor a logic 1.

You now subtract N8's frequency (64MHz)from this stage's Fl, and the result, 6.25MHz,becomes the new Fl for the next stage. Takingthe new value of Fl (6.25MHz) we comparethat with the next lower N value's frequency.

The frequency associated with N7 is32MHz, which is bigger than the new Fl, soN7 is not needed and becomes a logic 0. Thepresent value of Fl passes on unchanged tothe following stage, using the frequencyassociated with N6. The frequency for N6(16MHz), is also bigger than Fl so N6 is also0, and Fl passes on again unchanged.

So, I'll start with the transmit frequency of70.25MHz.The N9 frequency (128MHz) is too great soN9 is 070.25 - 64MHz = 6.25MHz so N8=1

N7, 6 and 5 are all bigger so N7, N6 and N5are 06.25 - 4MHz = 2.25MHz so N4 = 12.25 - 2MHz = 0.25MHz so N3 =1N2 frequency, 1MHz, is too big so N2=0NI frequency , 500kHz, is too big so N1=0250kHz - 250kHz leaves no remainder soNO = 1 and lines A5 to AO are all 0.

Synthesised Frequency

To obtain a synthesised frequency ofN4, N3 and

N1 floating (at logic 1 remember) and put indiodes to pull all other lines down to logic 0.Now let's go onto finding the values for thelocal oscillator frequency at 80.95MHz.

Again N9 is 080.95- 64MHz = 16.95MHz so N8 is = 1Again N7 frequency is too big so N7 = 016.95 - 16MHz = 0.95MHz so N6 = 1N5, 4, 3 and 2 frequencies are to big, so N5,N4, N3, and N2 are 0950 - 500kHz = 450kHz so N1 = 1450 - 250kHz = 200kHz so NO = 1200 - 200kHz leaves no remainder, so A5 = 1As there was no remainder to process, A4, A3,A2, Al and AO are all 0.

So, lines N9, N7, N5, N4, N3, N2, A4, A3,A2, and Al all require diodes to pull them tologic 0. Lines N8, N6, N1, NO and A5 are allleft floating at logic 1.

It's not difficult is it? And now that youknow the method you can go ahead andcalculate the other frequencies needed for theparticular channels you require on 70MHz. Asan aid, I've reproduced the diode requirementsfor the popular f.m. channels in the chart.

Enjoy Four Metres

I hope you enjoy building the Martlet andusing 'four metres'. It's a great band and oftenneglected.

So, get busy and show everyone thatthere's more to 70MHz than packet radio! Letfly on four!


Fig. 1: The mainp.c.b. andassociatedcomponent overlay(note that thecapacitors C8 andC12 shown in thecircuit diagram, arein fact integral to T1and T2respectively). Themethod used forpreparing the mainand front panelp.c.b.s plug andsocket arrangementis described in the'Errors & Updateand Shopping ListExtra' panel onpage 44.

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CONSTRUCTION

WR340 (Mantel Front Panel) ©PW Publishing Ltd 1995

S Meter

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Fig. 2: The PW Martlet front panel p.c.b. and associated componentoverlay. The special technique needed for installation of thechannel selector switch is described in the 'Errors & Updates andShopping List Extra' panel.

Clive Hardy G4SLU reports on the PW Martlet project: At the timeof writing, I've built the main board of the PW Martlet using a pre-production version of the p.c.b. As can be seen in the photographs(page 35 March, page 36 April PW issues), there is a lot of inter -board wiring on the original pre -publication design. However, fromthe experience I gained from building the prototypes, changes havenow been made to the Martlet design so that the matrix and mainboards now plug directly together. This greatly reduces the amountof wiring, which has to be good news! The 'S' meter has also beenadded since the original design.

I obtained all the components by mail order, although not froma single source. Construction of the main board was quitestraightforward. However, I did make one change. Instead of thetwisted wires in the receiver front end I used a 3.3pF capacitor.Initial checks on the board are done before the i.c.s are fitted.Without making any adjustments, the test results were extremelyclose to the values required. To complete the testing, the board wasconnected to the original p.a. and matrix boards. With the i.c.sfitted both v.c.o.s locked up straight away. As soon as an antennawas connected packet signals were heard on 70MHz. Theadjustment needed to optimise the receiver tuning was almost nil.On transmit, 10W was easily obtained. The transmitted audio wasreported to be a little quiet, which could have been themicrophone. However, more than enough audio was obtained bychanging R32 from 221(11 to 2.2ki2. So far, the Martlet has proved adelight to build. G4SLU

Errors & Updates And Shopping ListExtras

Coils L7, 8 in the original circuit diagram (page 33 Marchissue) should be S18 Blue, not S18 Green as shown.

Pin headers on main p.c.b. These are made up fromone 36 -way single row p.c.b. plug (Cirkit stock No. 10-70173). Break it up into two 12 -way and three 4 -waysections. Also needed- p.c.b. sockets. (Cirkit stock 10-70123 (6 -way) x 4, and Cirkit stock No. 10-70121 (4 -way)x 2.

For the audio and squelch: you will need two cableshells - Cirkit stock No. 10-0495 (5 -way) x two. Alsoneeded are crimp terminals Cirkit No. 10-04077 (10 off).

There is a special technique for mounting the channelchange switch on the matrix p.c.b. The switch has the twocommon contacts inside a ring of made of the othercontacts.

This outer ring makes it difficult to get a soldering ironin to solder the common contacts to the p.c.b. So cut thecommon contacts short and solder a 50mm length ofinsulated wire onto each contact.

Then solder the other ends of the leads onto thecorrect pads on the p.c.b. Gently bend out the ends of theconnections on the switch and place the switch, correctlyorientated of course, against the p.c.b. and solder eachcontact in place.

The switch should now be firmly held against thep.c.b. For the inter-p.c.b. connections for the volume andsquelch controls a short 5 -way lead has to be made upwith the two 5 -way cable shells and contacts. Use fivelengths of insulated wire (but preferably short lengths ofminiature audio coaxial cable) about 60-70mm long.Although the terminals are really 'crimp' types you cansolder them quite easily instead.


PTTO

13.8'RX

13.1-8V0

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Diode Matrix Programming Chart

Frequency

MHz

70.250070.262570.275070.282570.300070.312570.325070.337570.355070.362570.375070.387570.400070.412570.425070.437570.450070.462570.475070.487570.5000

Receiver

NNNAA A A A N

Transmitter

N A A A A A2 1 0 5 4 3 2 1 2 1 0 5 4 3 2 1

*

rt

= fit diode, i.e set to logic "0"

*

*


THEORY

Examining AnImage ProblemMurray Ward G3KZB opens his RAE notebook again and, looks further into theproblems of image interference.

In the first part of this article that appearedin the February 1995 issue of PW, Iexplained what second channelinterference is. I showed that it happensin the mixer stage of a superhet receiver. I

also showed that the image (or secondchannel) frequency is always separated fromthe wanted frequency (the one we are tryingto listen to) by twice the i.f.

This time, I'll show how designers reduce(hopefully they prevent) the problem fromhappening. To avoid second channelinterference, we must stop the imagefrequency getting into the mixer. Thediagram, Fig. 1, shows how designers try toachieve this.

Some methods used include a band-passfilter (called a preselector on some olderreceivers) at the antenna input. This filteringmay involve a stage of r.f. amplification. Theyalso add good screening so that the imagefrequency does not 'leak' in via the wiring.

The diagram of Fig. 1 shows the layout ofa 'typical' receiver, with only a single,unspecified, i.f. Many designs use a high i.f.because the wider apart, in frequency, thewanted and image frequencies are, the easierit is to separate them.

A modern communications receiver islikely to be a double superhet. But it couldbe a triple conversion, but let's not get toocomplicated.

A double superhet has two i.f.s. and inthis case, selectivity (the ability of the circuitto respond to the frequency we want and

reject all others) is provided by the second i.f.which is usually low in frequency comparedwith the first i.f.

In fact, using a high first i.f. has twoadvantages: it minimises the risk of second

channel interference; and the designer canprovide continuous coverage over a widefrequency range more easily. Amateur bandsonly receivers are a dying breed.

PW

QuestionsThe following multiple choice questions are similar to those that you will find in the RAE.

Answers at Bottom of the page.But... no cheating!

Q1 a superhet is tuned toWen

3.5MHz, its local oscillator is running

at 4.0MHz.The second channel frequency is:

(a) 500kHz(b) 1.0MHz(c)(d) 4.5MHz h

Q2 Image interference in a superhetcan be minimised with:

(a) a narrow 1.1. bandwidth(b) a stable local oscillator(c) a high i.f.(d) a wide dynamic range

Q3 A superhet has an i.f. of 10.0MHz.When receiving a signal on 29.0MHz,the frequency of the local oscillator is39.0MHz.The image or second channel frequencyis:

(a) 49.0MHz(b) 58.OMHz(c) 68.0MHz(d) 87.0MHz

Q4 Second channel (image)interference is caused by:

(a) abnormal propagationconditions

(b) overdriving the transmitterpower amplifier

(c) deficiencies in the receiver(d) strong transmissions on

adjacent frequencies

V

Fsig

Fimage

Band-passFilter

RF stages

ig

These stages increase front-endselectivity and so reduce the

image signal reaching the mixer

The whole front end (as shown here)should be well screened from the

rest of the system

Mixer

Localoscillator

(First)IF stages

A high if makes iteasier to separate

the image andwanted signals

Demodulatorstage

of

AF (audio/stages

Fig. 1.

Again no cheating please, here are the answers. (3) tij (el Eb (if zb (p) to


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FEATURE

se

The Eddystone EC10 and associatedmains power supply unit.

The EC10 communication receiverwas produced by the Eddystonecompany from the early 1960sonwards. It's a 10 transistor, five bandreceiver covering 550kHz to 30MHz.

Capable of a.m., c.w. and s.s.b. reception,the EC10 can be powered from either internalbatteries or an external supply. The batteries aresix size D (the old U2) 1.5V cells, held in acarrier at the rear of the set or via the mainsadapter that replaces the battery carrier.

Lightweight Receiver

The EC10 is lightweight and quite modern in itsstyling. With its blue -grey all metal case andchassis along with a cast front panel andchromium plated 'grab handles' mean the sethas excellent rigidity and a solid feel to it.That's something often lacking in many modernplastics cased receivers!

Weighing in some 6.3kg (141b) withbatteries, with dimensions a fraction over 152 x304 x 203mm (6 x 12 x 8in). The scaleprovides 228mm (9in) of tuning span which,combined with the slow motion drivearrangement, gives a very easy tuning rate onall but the highest range.

SKI Ll

III II IICl20 350p

Longwireantenna

C220 350p

Ground

Fig. 1: Circuit of simple antenna tuningunit la.t.u.) suitable for EC10 (see text).

Fig. 2: Method used to allow negativeearthed equipment to be used withEC10 receiver (see text).

IPositive

GP....... -iw signal

+` i 1-1111-:

neg. ground

1 Negative

oi It's a Classic...The EddystoneEC10 Receiver

Ben Nock G4BXD looks at another 'classic'. This timeit's the Eddystone EC10, a transistorised receiver, a

pioneer in its day which is still in use in many shacks, includingthe PW offices where you'll find no less than five EC10 owners!

The tuning coverage on the EC10 is brokeninto the following ranges: Band 1 covers 18 to30MHz. Band 2 covers 8.5 to 18MHz. Band 3covers 3.5 to 8.5MHz. Band 4 covers 1.5 to3.5MHz. Band 5 covers 550kHz to 1.5MHz.

Circuit Design

The circuit used in the EC10 receiver is asingle conversion design. Working with anintermediate frequency (i.f.) of 465kHz, itemploys six 0C171, an 0071, three 0083transistors and three diodes.

The r.f. amplifier, an 0C171, operates ingrounded base configuration. The designallows automatic gain control (a.g.c.) to beapplied to the r.f. amplifier and the first i.f.amplifier. The r.f. gain is adjusted from thefront panel mounted control, which also variesthe a.g.c. characteristics.

The ECIO's local oscillator, an 0C171,operates on the high side of the signalfrequency on all bands. The I.o. signal is fed tothe emitter of the mixer transistor, an 0C171,with the r.f. signal being applied to the base ofthat device.

Two stages of i.f. amplification areemployed in the EC10. The i.f. stage uses0C171 transistors with the a.g.c. and r.f. gaincontrol affecting only the first stage. A diode(0A70) is used in the primary of the first i.f.transformer to help the receiver under strongsignal conditions.

The output of the beat frequency oscillator(b.f.o.) when it's in use, is fed to the outputtransformer of the first i.f. stage. Because ofthis, the b.f.o. signal is amplified by the secondstage along with the signal being received.

A diode detector, an 0A90, is used with therecovered audio passing to the audiofrequency (a.f.) gain control. The a.f. signal isthen fed to the audio stages.

In the audio stage an 0071 preamplifier isused to feed a driver transistor. This drives twoOC83s in a push-pull configuration.

An audio filter is capable of being switchedin circuit on the receiver. This has a peak ataround 1 kHz and is useful for c.w. reception innoisy band conditions.

The ECIO's audio output is quoted asexceeding 1W and a small loudspeaker isenclosed in the case and there's a jack socket

for low impedance headphones. Usingheadphones automatically mutes theloudspeaker when the jack plug is inserted

A further diode, an OAZ203, provides aregulated supply from the main supply line.This feeds the r.f., mixer, oscillator and b.f.o.circuits with 6.5V. The remaining circuits in theEC10 are supplied with the 9V from the batterypack or mains unit.

As it's an older receiver, the EC10 has a'positive' earth. But, when it's powered byeither the internal batteries or the mains unit,the positive earth won't cause problems if theset is used with other equipment as the supplyis self-contained.

However, if you intend to use the EC10mobile, it's a different matter. The receiver willthen need to be powered from a separatesupply and not from the car battery (as modernvehicles are of course negative ground).

Antenna And Earth

Antenna and earth sockets are provided on theEC10's rear panel. They're marked Al, A2, AE,and Earth, for either balanced or unbalancedantennas.

Short or long wires can be connected to theEC10, along with a balanced fed antenna. Ifyou intend using a single long wire end fedantenna, then this should be connected to Alwith a shorting link between AE and Earth.

A coaxial cable feed from a suitableantenna also uses the combination of socketsI've just described. In this case the braid goesto Earth, with the inner core going to Al.

However, if you decide to use a balancedfeeder, then it should be connected to Al andAE. And in this case the shorting link must beremoved.

The popular type of short rod antenna canbe used with the EC10. You should connectthem to the A2 terminal and again the AEsocket is shorted to the Earth socket.Incidentally, some useful reduction in thelocal noise received may be gained if youcan provide a good earth connection for theEC10.

Finally, as with all random length long wireantennas, some form of antenna tuning unit(a.t.u.) is advisable. I've suggested a suitablesimple circuit in Fig. 1.


Servicing The Receiver

The EC10's circuitry is a very straightforwarddesign. So there should be very little problemin servicing the receiver should it be required.

The front end, r.f., oscillator and mixertogether with the coils are contained on oneboard. The remainder of the EC10's circuitry ison a second p.c.b.

I've provided some typical voltagereadings, which are given in Table 1. Theyshould be taken with a meter of at least2042/volt sensitivity, measured negative withrespect to the set case and ground. Controlsare set to: Range 1, 20MHz, r.f. and a.f.controls at maximum, the a.g.c. off and b.f.o.on.

Receiver Alignment

If your receiver requires alignment, Table 2will help. It provides the location referencesfor the core/trimmer associated with eachalignment frequency.

Alignment is carried out by selecting thecorrect high frequency tuning point and theninjecting a modulated signal from an accuratesignal generator. You then adjust theappropriate trimmer, select the associated lowfrequency point, then adjust the appropriateinductor.

The procedure is repeated, reducing theoutput of the signal generator to preventoverloading. You should continue until theECI 0 is correctly aligned and no furtherimprovement can be gained.

A good enough 'tool' for measuring thereceiver is the old human ear! But, if higheraccuracy is required then some form ofvoltage measurement of the audio output canbe used. (One method uses a resistor acrossthe speaker terminals and a voltmeterconnected across it, with a modulated signalbeing supplied from the generator).

After alignment, set the generator to465kHz, with the receiver to 560kHz andincrease generator output until a signal isheard. Then Adjust LI for minimum output, re-checking L6 at 560kHz afterwards.

Possible Modifications

Although there are several possiblemodifications for the ECI 0, I haven't tried any

Table 1: Voltage measurements

Fig. 3: Annotated photograph showing location of inductors and trimmers foralignment purposes (see text and Table 1).

on my set. However, one modification thatmight be considered is the addition of aproduct detector to improve s.s.b. reception.

There are a few product detector kitsaround. But you must remember though thatany new devices fitted are going to be of thewrong polarity.

Don't forget that a negative ground unitcannot be connected directly to a positivegrounded set. In other words you could notconnect the 'grounded' section of the newp.c.b. to the chassis of the ECI O.

The EC10's earthing problem can beovercome though if the unit is isolated fromthe set ground. With the method I suggest, Fig.1, the supply adequately decoupled withcapacitors between both negative and positiveof the unit and set. It permits the a.c. signalsinvolved to pass through, while preventingshort circuiting of the d.s. supply.

If you do modify your ECI 0, the feed fromthe b.f.o. to the first i.f. transformer wouldneed removing and taking to the new productdetector. The received signal could then betaken either from the transformer side of thedetector diode or the collector of the secondi.f. amplifier via a blocking capacitor.

Device Collector Bank EmitterTable 2: Alignment

r.f. amp. Tr1 6.35 1.0 0.68mixer Tr2 6.5 1.2 1.1 Range Freq.local osc. Tr3 6.3 1.35 1.2 Osc.1st i.f. Tr4 5.6 1.15 0.87 Mixer2nd. i.f. Tr5 7.5 0.7 0.4b.f.o. Tr6 6.3 0.75 0.6 1 29.0 C39a.f. amp. Tr7 4.0 0.97 0.9 2 18.0 C40driver Tr8 8.9 1.5 1.5 3 7.5 C41a.f. output Tr9 9.1 0.15 0.07 4 3.5 C42a.f. output Trl 0 9.1 0.15 0.07 1400 C43

The al. gain potentiometer could beswitched between the output of the diodedetector or the product detector. But a ADresistor would need switching in place of thea.f. gain potentiometer when you're receivings.s.b., to maintain the a.g.c. load.

Fortunately, the EC10's original b.f.o. push -to -make switch has spare contacts. Thesecould be used to re-route the audio from eitherthe diode detector or the new productdetector.

Useful Receiver

All things considered I think that the ECI 0 is auseful receiver. However, it does have slightdrawbacks for the shortwave listener.

For example, the receiver has a crampedbandscale on the highest range. Additionally,there's no antenna 'peaking' control and fixedselectivity.

Despite my reservations, considering itssize and weight the EC10 proves a very usefulreceiver for those with either a limited budgetor limited space in which to pursue the hobby.Many enthusiasts would be well advised toseek out one of these sets at the next rally andhave a good old play with it. I'm sure it will bemost rewarding. PW

Trimmer Freq. CoreAntenna Mixer Osc. Antenna

C3 C21 18.0 L12 L2 L7

C4 C22 8.5 L13 L3 L8C5 C23 3.5 L14 L4 L9

C6 C24 1.5 L15 L5 LIOC7 C25 560 L16 L6 L11


FEATURE

John Hines GOPNX shares hissailor's story of how he puthis newly acquired radioskills to the test on a cruisearound Spain and Portugal.

Yacht Pushpa atanchor in

Munros, north-west Spain.

As my callsign GOPNX shows, I amfairly new to amateur radio.However, I have discovered thatalthough there are plenty oflicensees who are also yachtsmen,

the combination is still comparitively rare. So,I'm going to share with you some of the joysand problems of operating Maritime Mobile(MM), or Mickey Mouse as some people say.

It was sailing that got me involved withradio in the first place. In 1990, my wifeMargaret and I were at anchor in our yacht,Pushpa, in Finisterre in Spain. We got talking tothe people in the only other boat in theanchorage.

There was a licensee aboard the other boatand he passed a weather forecast to us,including a gale warning. This was a helpbecause we had been unable to receive Radio 4in Northern Spain for some weeks.

The anchorage was less than ideal forletting a gale pass through, so both yachtsmoved up to Corcubion. The gale duly arrived,and I learned enough about the value ofamateur radio to yachtsmen from the amateurTrevor Liberson GOMKO to convince me that Ishould learn more.

Within a month, I was wishing that I hadalready learnt about radio. I thought this waybecause I fell between two pontoons inCorunna, broke a leg and had to fly home whileMargaret brought Pushpa home.

The complications of arranging things withfriends in Britain would have been reduced ifwe could have talked from the boat rather thanfrom coin box 'phones, especially as many ofthe calls were to Ian Brotherton G2BDV, asailing friend.

Joined Class

That winter I joined an RAE class, wrote acomputer program to teach myself Morse andreceived help and encouragement from severallicensees that I already knew. By the end of July1991, I had an Icom IC -720A, a manual a.t.u., athird battery in the boat and my own licence.

I had a month to practice at home, shoved a

bag of plugs and wire into a bilge locker beforeit was off to Lymington to cross to the Bay ofBiscay. We intended to spend the wintersomewhere in the sun!

My yacht Pushpa is only 32ft long. Fittingan antenna into such a limited space is not easy.

Sure, we have a mast 43k high and lots ofsea water all round to provide a good earth. Butthe mast is used to support sails and I wasinclined to give these priority, after all, I havebeen sailing for over 40 years and had not hadmy licence for 40 days!

I made two dipoles for the 14MHz band,one ordinary and one using the CFR designcalled a 'Cobra' from the Orr -Cowan book onwire antennas. I hoped that the second wouldevade the impossibility of providing a route totake the feeder away at right angles to theantenna itself.

I'd fitted a second burgee halyard but hadbeen warned to keep the antenna away fromthe mast and rigging, (not easy while sailing). AG -whip mobile antenna had been part of thedeal with IC -720A so I'd bought a bracket for itand fitted that to the self steering gear which isout of the way at the stern, intending to keep thedipole for when at anchor.

I had already been told about the UKMaritime Mobile Net. I'd been listening to itduring the preparation stages, had identified oneof the Net controllers and written to him to feedbasic information on the boat and crew to himso that my arrival on the net would not come asa surprise. And, as you will see, I still had a lotto learn.

Corunna Contact

A week later, we were in Corunna. I soonhauled up an antenna and made contact withthe morning controller of the UK MM Net BillHall G4FRN.

I must acknowledge the amount I learnedby listening to him and to Bruce G4YZH, theevening controller. Both were so efficient,organised and calm that I shall always think ofthem as admirable examples to try to follow.

I'd arranged a morning schedule with the

Lymington members. Frequent contacts weremade on 14MHz as we moved along theSpanish coast. When looking for a collectiveterm to call them, it became natural to refer tothem as 'The Friends of Pushpa'.

One Lymington member spends severalmonths a year near Bordeaux. While there, hehas regular contacts with Lymington on 7MHzand I found myself included. These contactswere made using the Cobra (although it had notbeen cut for this band), usually while not underway, because it tended to get very close eitherto the sails or the wire rigging.

I was keen to get the G -whip workingbecause it was easy to have in place whilemoving. I also regarded it as my emergencysystem. Then, in our first Portuguese port, Vianado Castelo, I met Geoff GOOHE.

Geoff dismissed all my attempts to have atuned antenna strung around the rigging, "justuse your a.t.u. to match the rigging" was hisadvice. So, I connected a bit of coaxial cable tothe backstay with a hose clip, ran a connectionfrom the outer to the lifelines and tried the idea.

Bingo! I could get an s.w.r. below 1.2 acrossthe 14 and 21MHz bands and below 1.5 on7MHz. This lash-up became the routine systemand the tuned wires went into the bilge.Contacts with the Lymington group and the MMNet continued as we worked our way South.

I had taken several radio books, whichbecame regular reading, even on some of thelonger and uneventful passages. We had aportable multi -standard TV on board and hadkidded ourselves that it was for weatherforecasts, but found that the MM Net, plusNavtex, met those needs so effectively that theTV was used more to watch entertainmentprogrammes.

The antenna studies produced anunexpected benefit because we were sometimesin places where TV coverage was pretty poor,such as a deep dock alongside a steel fishingboat. In any case, the cabin table is barelyabove sea level, so putting the set there meantthat the TV antenna was having a struggle tofind a signal.

I bought a length of fencing wire, salvageda bit of wood from a skip and made a Yagi for


the I V. This could be propped on the boom andsometimes made a worthwhile difference.

The TV antenna experiments really paid offwhen we reached Gibraltar. The owner of anearby yacht found that he couldn't get apicture although he had just paid a boatyardf200 to install an omni-directional antenna atthe masthead. I fetched my fencing wire, foldedit into a quad and attached it to his feed linewith insulating tape, not even soldering it.

The picture was perfect and he got hismoney back! It was also in Gibraltar that wemet George, a Slovenian radio amateur whowas just beginning a world cruise in a tiny boat.

George was having problems ontransmission but I found that I knew enough todiagnose them and provide a solution. Maybeeven the RAE is a bit tougher than the formerYugoslavian equivalent examination?

Winter Quarters

By late November we had settled in Puerto dela Duquesa, 20 miles north east of Gibraltar,which was to provide our winter quarters. Aroutine developed, whereby we would listen tothe evening MM Net while having supper, notoften joining in.

We usually just learned how things weredone, by listening. But we also got a lot ofentertainment for hearing what people used theNet for.

The Net provided a record of where boatsat sea were so that the controllers were ready tocope with any emergencies. The variety of othertopics was interesting and we heard peopleasking about resources of various ports aroundthe Mediterranean, including FAX numbers, theavailability of shot blasting and also makingarrangements to return the ship's papers wherethey had been left behind.

We heard reports of a yacht which hadbeen stolen, and of the yacht and thief beingfound. One of the most dramatic items waswhen we heard a man whose mast had fallendown when he was two days out from theCanaries, injuring his wife.

Within 20 minutes there was a doctor onthe frequency, giving advice. A few days later,the casualty was in the Cap Verdec, where

people were ready to repair both wife and boat.A couple of weeks later, we heard him

restart his trans -Atlantic passage. We couldalmost hear the sigh of relief from severalhundred members of the Net when heeventually arrived in the West Indies.

I then decided to re -build the connectionsto the backstay, to tidy up the lash-up that hadbeen built in Viana. The test on the re -build wasinteresting.

I broke into a contact, just requesting acheck -on signal, to ensure that the system wasworking. "Good signal" said one man inEdinburgh, "but let's see what the man I'mtalking to says". "No problem here inTasmania", said the other.

There were several other live-abroads in thePort who were also licensees. There was anAmerican lady who had crossed the Atlanticwith only her dog for crew had a regular c.w.schedule with her father in Indiana.

We also had Bob G4VUF who was a greathelp and who introduced us to Bruce G4YZH,the evening Net controller, who had becomesuch a part of our lives. Bruce's wife, SueGOOEP also provided advice on places whichwe ought to visit.

Resumed Travels

When the spring came and we resumed ourtravels, we sailed right along the SpanishMediterranean coast. We avoided longpassages, in fact, doing no overnight passagesbecause one of the objects was to see thecountry.

One evening, I was just setting up the set forthe evening Net, without paying much attention .

to what was being said, but Margaret heard amagic phrase from Bruce. I checked in and wastold that daughter Jan had passed some exams.

If there had been any doubt before,Margaret was now convinced about the meritsof amateur radio. So, that night I began apreparatory course in radio theory with a classof one.

In France, we lowered the mast, re -installedthe G -whip and entered the canal system. I hadto remember that I was now F-GOPNX, notGOPNX/MM, which had become so much of a

The Pushpa in a lock in the French canThe G -whip is the black line against t

centre support for the mast at the ste

1.

reflex that it was difficult to shake off the suffixeven when we got home.

It was a new kind of sailing, but we foundthe benefits of radio continued. An antenna Isaw on a French lock -keeper's house led to aquery to the lock -keeper who rushed off to get aQSL card to give to me.

A earlier discussion in Duquesa with BobG4IHH who keeps a boat on the Canal du Midisent us looking for a restaurant where we hadall we could eat and as much wine as we coulddrink, for 38 Francs each, about f4. Althoughnear the canal, we wouldn't have found itwithout his advice.

We had been wondering about where tohave the mast raised. The first possible placeafter the last low bridge was in Bordeaux, butthe reference books were discouraging, more asa result of what they left unsaid than of whatthey said.

It would be possible in Royan, but that wasabout 100 miles beyond, with a fair amount ofpotentially rough water in between. The idea ofgoing there with the mast on deck and unableto set sail felt risky.

In between was Pauillac, the right side ofthe more open water, where mast installationmight be possible, but our books were vague.One of the 'Friends of Pushpa' was in hisholiday home nearby. He had the opportunityto visit the yard, obtained the information andfed it back to us on one of our morningschedules, yet another practical benefit of radio.

However, the mast actually went up againin Bordeaux, after we had surveyed thearrangements for ourselves. We felt more likebeing abroad a sea -going vessel, and couldrevert to the back -stay antenna system.

Once Home

It was interesting that, once home, we found along forgotten lightning protection strap, whichhad been making a capacitative connectionfrom the mast base to the sea via a keel bolt.The antenna had not been working in the way Ihad thought, but as I said I am a 'new boy'.

However, the length of back -stay plus mastplus earthing strap is over 100ft, around oneand a half wavelengths at 14.3MHz. In anycase, it had worked, the basic requirement forany antenna.

Bearing in the mind the value of amateurradio to yachtsmen, especially for emergencycommunications, some things we heard were abit surprising. We noted how one (?) personwould start to tune on the MM frequency, forminutes at a time, shortly after the morning Nethad begun.

It was done so often that it looked like adeliberate attempt to disrupt the Net. We notedhow a couple of German stations would start acontact 10 minutes before the evening Net, slapon 14.303MHz, apparently just for the sake ofpushing the Net somewhere else.

And since we got home? Well, Margaret isnow GOTXN. So she will be able to talk homeand we will be better equipped with operatorsnext time we leave the house to the 'children'.

PW


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1r52 Practical Wireless, May 1995

FEATURE

The Practical WirelessDatacard GuideKevin Nice G7TZC reflects on what you can and can't do withthe PW repeater Datacards for 144 and 430MHz and thepainstaking process of producing them.

you can please some of the peoplemost of the time, or most of thepeople some of the time, but youcan't please all of the people all ofthe time. So the saying goes. Well,

when I \ %as assigned the task researching andcompiling the latest Repeater Datacards forPractical Wireless I wanted to maintain thehigh standard of previous versions.

In preparing the Datacard I was keen tocheat the saying and 'please all of the people,all of the time' - or at least those who userepeaters and roam the country. It is, after all,these amateurs that the Datacards are primarilyaimed at.

Some of the telephone calls that have beenreceived at the Editorial Offices of PW, leadseveryone on the Editorial Team to think thatthe purpose of the Datacard has been missedby a few, hence these words of explanation onthe spirit of intent of these invaluable guides.And as an aside, it has led me to theconclusion that a more detailed book isrequired, watch this space for more news onthat front.

Problem Solved

Many years ago there was a difficult problemto be solved at Practical Wireless, many headswere scratched, hands wrung, and brainsLicked.

70cmRepeaters

11.1

au, d;rti5,

r

,, 1.111 110

tr.

Then out of the mists of confusion there wasa clear light of reason. The answer to theinterminable problem was nigh, and thePW Repeater Datacards were born.

There have been imitations andalternatives since the inception of oursolution. but there have been none tomatch either the simplicity or functionalityof the Datacard.

The way in which the Datacardfunctions is unique. We've copyrighted itso that it stays that way. Much care,thought and effort has gone into theproduction of the latest versions.

All you Repeater Keepers readingthis will know what follows already. But, forthe benefit of all the other repeater users, I willexplain how the data was gathered to producea most invaluable v.h.f. mobile accessory.

I was keen to ensure a highly efficientmethod of gathering the most up-to-datelocation and frequency information for the UKv.h.f./u.h.f. network. To this end at PW wereasoned that the only safe source for this datawas the Repeater Keeper, after all, they are thestation licensee and legally responsible formaintaining the station.

The most efficient way I could devise forgathering the frequency and locationinformation from the 'Keeper, was to supply amap with the information that was alreadyheld on file to the keeper. The map was then

returned with confirmation that theessential information was correct orannotated with updated details.

Once gathered, and by the way therewas a very high return rate - thank you,this information was transcribed on toboth master art work for the appropriatecard and a listing for the use on the rearof the card.

-a03

YAESU

Mobile Guide

It's worth noting several importantthings at this point. The 'Datacard isintended as a guide only, for usewhile operating mobile, thelocations of repeater sites are not toscale.

While it's quite possible toproduce a guide to scale, it wouldhave no more functionality than theDatacard, which has been producedat its current size to enable easy useand storage in the mobileenvironment. After a recent bout oflong distant travelling around our

uhalftrr r..1i,,iron :: ..,, ,T,

- -4

' \

t \4 ,7.inin

& 4 ,

fair isles, I know I wouldn't be without mine.I wish to take this opportunity of wishing

all the users of the card maximum enjoymentfrom the use of your card. If you have anysuggestions related to future cards then pleas)write to me at the Editorial Offices. I also wantto thank all the Repeater Keepers that weresurveyed for their essential co-operation.

On a final note, judging by the favourablefeed back, the Datacard has had a high level ofsuccess and we've pleased most of the peoplemost of the time! PW

If you missed the issues of PW containingthe Datacards back issues of the December'94 and March '95 issues are available forf2 each from our Post Sales Department.The 2m (144MHz) Repeater Datacardappeared in the December 1994 issue andthe 70cm (430MHz) card in the Marchissue.

If you'd like to find out more repeateroperation you may be interested to readthe previously published articles'Repeaters - What They Are And How ToUse Them' and 'Repeaters - The UHFSide'. These articles appeared in theNovember 1994 and February 1995issues of PW respectively, back copies areavailable for £2 each from our Post SalesDepartment.

To order your copies contact Ann orMichael at PW Publishing Ltd, Post SalesDepartment, Arrowsmith Court, StationApproach, Broadstone, Dorset BH18 8PW.Tel: (01202) 659930FAX: (01202) 659950.


Ron Ham invites youinto the warmconfines of the PWvintage wirelessshop...this month he'slooking at twointeresting postSecond World Warreceivers from Bush,and also commentson readers' letters.

W, 'come to the

\N. orld of 'valve &vintage'equipment. And

this month I'm looking back at thetime long before the advent offrequency modulation (f.m.)broadcasting on v.h.f.

Before Band II (nowadays 88to 108MHz) transmissions therewas a great demand for goodquality long and medium wavereceivers. Particularly so after theSecond World War whencustomers began to replace theirWartime Civilian Receivers.

To meet the demand. Bushbegan production of their popularDAC range of mains portablereceivers. The early versions. likethe DAC90, Fig. 1, used theMullard Red 'E' valves and thelater sets, like the DACIO, Fig. 2,used the smaller glass valves.which I've shown in Fig. 4.

The Bush sets were attractivein appearance and were wellmade. The large loudspeaker,inside the robust Bakelite cabinet,ensured good sound reproduction.

Domestic Use

The DACIO range were suitablefor domestic use at the bedside,

kitchen and small sitting rooms.Although similar in constructionand suitable for the generaldomestic work, the DAC10, withits push button and manual tuning.was ideal for blind people.

Blind people found theDAC10 was useful because astation could be selected bypressing a button. In fact, thisBush receiver was one of the setschosen by the Wireless For TheBlind organisation.

Frame Antenna

Both the Bush sets had a circularframe antenna fitted near the frontend valve on one side of thechassis. This can be seen on theleft of the DAC90 and DACIOchassis in Figs. 3 and 4respectively.

The receivers illustrated canoperate on a.c. and d.c. mainssupplies and consequently have alive chassis. So, be very carefulwhen you carry out any work.Incidentally, a warning notice tothis effect can be seen on thebutton tuning plate of the DACIOin the centre of Fig. 5. Editorialnote: As a.c.1d.c. receivers arestill very common. readersinterested in working and

Fig. 3: Rear view of the DAC90.

alveintage

Fig. 1: The BushDAC90 (see text.

Fig. 2: The BushDAC10 usedminiature glass -based valves(see text.

restoring them are advised toinvest in a mains isolatingtransformer. They are notparticularly cheap. hut provide anextra safeguard for all amateurradio workshop servicing.

Valve heaters on the Bushreceivers are wired in series. Thedifference between their totalvoltage and the mains voltage ismade up with a large wattageballast resistor. This is mountedon the right of Fig. 3 and betweenthe output valve and rectifier onthe centre right of Fig. 4.

The valve line up in theDAC90, Figs. 1 and 3, comprisesone each of CCH35. EF39.EBC33, CL33 and the rectifierCY3I. The DAC 10 has a UCH42,UF41, UBC4I and UL41. plusthe rectifier which I think is aUY4I.

Great care must be takenwhen removing the small glassvalves from their sockets. This isbecause they have a glass locating

'pip' on the side, just above thepins, which can snap off if forced.

Each valve -holder has a clip.see Fig. 4. around it to hold thevalve in position. It's best to easethe pressure on this clip with ascrewdriver before the valve isremoved. But don't forget todisconnect the mains supplyfirst.

The heater current for theMullard 'Red Es' valves is 20mAwhereas the miniature types usedin the DACIO, are 100mA. Therectified h.t. voltage for the valvesis supplied from the cathode ofthe CY31 in the DAC90 and theUY41 in the DACIO.

The electrolytic reservoir and'smoothing' capacitors for thereceivers are housed in one 'can',with a common earth point. Thecapacitor is mounted under thechassis, top centre of Fig. 6, ofthe DAC90 and on the top of thechassis, centre of Fig. 4. on theDACIO.


Fig. 4: Inside view of Bush DAC10. Notethe 'live chassis' warning (see text).

Dismantling TheReceivers

Let's now look at dismantling theBush receivers. The loudspeakeron the DAC90 is bolted to thechassis, top centre Fig. 6 andcomes out with it. On the DAC 10it's fixed, along with the outputtransformer, to the cabinet.

There are two holes in the baseof the DAC90's case for access tothe screws that hold the frontknobs to the shafts. The screw forthe large tuning knob is found onthe tuning capacitor's spindle justabove the chassis inside on the leftof Fig. 3.

The control knobs on each sideof the DACIO remain on theshafts, Fig. 5. when the chassis isremoved. However, before furtherdismantling there are three wiresto release from the frame antenna

Fig. 6:

Fig. 5: The receiver manufacturers tookgreat care to ensure that users wereaware of the risks involved with 'livechassis', hence the warning under thepush-button tuning plate on the DAC10.

on the DAC90 and two from theoutput -transformer on the DACIO.

The dial and press buttonescutcheon on the DAC10. Fig. 7,is secured by a screw in eachcorner. This can be removed fordial cleaning, button labelchanging and must be taken offbefore the main chassis isremoved. (Don't forget todisconnect the mains!)

However, unlike the DAC90with its orthodox back cover, thecabinet on the DACIO almostsplits in two for access. It does thiswhen the four recessed bolts on therear of the cabinet are removed.

Military Radio

Last June John Easterbrook (IsleOf Sheppey) put his extensivecollection of military radio gear on

Both the Bush DAC90 and DAC10 receiversemployed 'common can'electrolytic capacitorsfor smoothing purposes.In the DAC90, thisphotograph, thecapacitor was mountedunder the chassis (seetext.

Fig. 7: Because of itspush-button tuningfacility, the Bush DAC10was useful for blindlisteners.

display at a D -Day show for theRAF Benevolent Fund. John'sSecond World War collectionincludes such sets as the AR88,BC348, CR100, PCR, R107 (Fig.8), R1155, and WSI9, 22, 31, 38and 52 sets.

Recently John acquired a pieceof German v.h.f. gear. Fig. 9. andwould like some informationabout it. The unit has the dial onthe right and a cathode ray tubedisplay on the left.

Have you any ideas readers? Ifso. please write to John at: GlebeCottage, 2 Warden Road,Eastchurch, Isle Of Sheppey,Kent ME12 4EJ. In his letterJohn kindly said "If you knowanybody at anytime who wouldlike a good Second World Wartransmitter - receiver display, etc.,please mention my collection".So, there we are folks, if you areorganising an event for the VEand/or VJ-Day Remembrance thisyear and would like John's supportdrop him a line.

Good Idea!

What a good idea! Mr K. N.Harvison (Northwich. Cheshire)has used a number of PP9. 9Vbatteries to make up the hightension requirement for the 1936Cossor 373 battery set in hiscollection. He also has a Philips617A using side -contact valvesand a PIX indoor antenna.

When Mr Harvison purchasedthe PIX the label and instructionswere missing, but he found theinformation he needed in a 1936copy of Practical And AmateurWireless. Briefly, the PIX antennahas an aluminium strip which wasoften put around the room justbelow the picture rail to blend inwith the border.

Navy Receiver

If anyone is looking forinformation about the ex -NavyB40 communications receiver, Isuggest they write to AndyJohnston at: 2 Kentmere Close,Kempston, Bedfordshire MK428HF. Andy is the proud owner of aB40 and has kindly offered help,so. readers please enclose an s.a.e.

and be prepared to cover any of hisexpenses concerning your request.

Well, it's time to close up the'shop' once again. But I lookforward to sharing those'vintage' memories with younext month. Cheerio for now.

Editorial Note: Our apologies forthe error that crept in regardingEFSO Valves. They are !octalbases, not octal. PW

Fig. 8: An R107 receiver is featured in JohnEasterbrook's collection of Second World Wartransmitting andreceiving equipment(see text).

Fig. 9: Can you helpsolve a mystery? JohnEasterbrook wants toidentify thisinteresting item ofGerman v.h.f.equipment (see text.


SpecificationsThe Mysteries Explairkata

This month Ian Poole G3YWX takes a look at the mysteries surrounding

Dynamic range is one,i the mostiiiportant receiver

,,,irameters, which isunfortunately open

to a lot of interpretation. I say thisbecause a receiver advertisedwith a specified dynamic range of110dB may not be as good asanother with a specified range of90dB.

The reason for the confusionis that there are several ways ofmeasuring dynamic range. As aresult, a closer look must be takento see exactly what is beingmeasured.

Range Important

First it's necessary to see why thedynamic range of the receiver isimportant. It's obviouslynecessary for the receiver to beable to receive weak signals.However, this sensitivity will beof little use if any strong signalson the band degrade theperformance of the set so that theweak ones can't be heard.

When the sensitivity of areceiver is measured in thelaboratory only one signal is used.But when the receiver isconnected to an antenna, it willbe subjected to an enormousnumber of signals of varyingstrengths.

Some signals will be veryweak while others will be verystrong. It's because of this that thereceiver has to be able to pick-upthe weak signals while there arevery strong ones close by. To beable to do this, the receiver mustbe capable of operating with awide variety of signal strengths,i.e. it must have a good dynamicrange.

Unfortunately it's notalways easy for the designer toachieve a good dynamic range.Often the sensitivity can beimproved at the expense of thedynamic range and vice versa. Tobe able to balance bothrequirements is the mark of agood receiver.

the dynamic range of a receiver.

Dynamic Definition

Before progressing any further it'snecessary to look at a definition ofdynamic range. Basically thedynamic range is the differencebetween the weakest signal areceiver can hear, and thestrongest it can tolerate withoutany noticeable degradation inperformance.

As a receiver's performancecan degrade in several differentways, the way in which theperformance is degraded mustalso be specified.

The weakest signal that canbe received is governed by thesensitivity. A term called theminimum discernible signal orm.d.s. is often used.

The m.d.s. is the weakestsignal the set can receive. It'sgenerally taken as a signal equalto the noise produced by the set.

The level of the m.d.s. signalis usually measured in dBm i.e.decibels relative to a milliwatt.Typically it might be around -135dBm for a bandwidth of 3kHz.

The bandwidth has to beincluded in the measuring. This isbecause the noise level isproportional to the bandwidth,i.e. the wider the bandwidth themore noise is picked up.

Limiting Factors

At the other end of the scale thereare two main limiting factors. Oneis the generation ofintermodulation products, and theother is blocking. As the onset ofthese effects occur at differentlevels, two figures can beobtained for the dynamic range.

Even when the specificationstates that blocking is the limitingfactor the level must be closelyviewed. Often a 1dB decrease inthe sensitivity is used whereas inother cases a 3dB decrease mightbe specified.

The intermodulation limiteddynamic range is a measure of thereceiver's ability to handle strongsignals without generating others

Fig. 1: Dynamicranges of a

receiver (seetext).

Signallevel

-20dBm

-45dBm

Blocking occurs

Intermodulationoccurs

Dynamic rangelimited byintermodulation

135dBm

Level of minimaldiscernible signaland noise floor

Dynamic rangelimited by'blocking'

that might mask out the weakwanted ones. In this case the levelof the intermodulation productsmust not be any greater than them.d.s., i.e. no greater than thenoise floor of the set. But againcare should be taken to inspectexactly how the measurementsare taken.

Modern Receivers

Most modern receivers will havean intermodulation limiteddynamic range of between 80 and90dB. If the blocking range istaken instead then its range islikely to be 115dB or possiblyeven more.

My comments illustrate theimportance of looking at the fullspecification and checkingexactly what the dynamic rangerefers to. The diagram Fig. 1shows a typical example but eventhen it's necessary to make surethat the test conditions are thesame when comparing tworeceivers.

If comparisons are to be

made between two receivers it'sbest to look at reviews made bythe same reviewer. This isbecause the test methods shouldbe the same, and directcomparisons can then be made.

That's all for thismonth, next time I'llbe unravelling

themysteries ofreciprocal mixing.Don't forget I'malways pleased toreceive details of anyspecificationmysteries you'd likeexplained on thispage.


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PAUL ESSER Y GW3K F E

Down south in Antartica(VP8) seems to be where itall happens nowadays. Thenews is that the Britishresearch station, FaradayBase, in Graham Land isclosing down. I've alsoheard that negotiations arein hand for the UkrainianAntarctic Research centre totake it over.

Still in the sub-antarticregion, South Georgia wasthe subject of a DXpedition.The expedition's callsignVP8SGP made some 15 000contacts. And continuingnoises are being made abouta team to activate SouthSandwich.

Top Band

Interest in Top Band isreviving. And don't forget,that while a big antennahelps radiate a decent signalon this band, for receive it'smore important to have aseparate low -noisereceiving antenna.

Recent Top Band activityaround 0400UTC has seen9J2B011.825MHz c.w.) and9J2GA I I.847MHz s.s.b.). Amite earlier A22MN waslivening up 1.827MHz. On theother hand, VK6HD reportsvia Top Band News that hecalled G3BDQ, G3KEV andG3YRO without success.

However, there was nomention though of VK6HD inG3BDQ's letter from John's0TH in Hastings. From thislocation John has managed154 American stations in thereporting month. Theseincluded KOHA (Nebraska),three from Iowa, N8SS inArizona which takes John upto 44 states.

The other G3BDQ TopBand contacts included4U1ITU, OHO/OH1AF, SU1MT,T99W, US8ZAL, ZA1AJ. Healso had a split -frequencyeffort with JH5FXP (the JAsonly have that tiny allocationabove 1.9MHz).

Still with 1.8MHz, AL7MXreports a serious receptionproblem. His Beverages(antennas) are being eatenby moose! (Or should that be'drunk' by a moose!).

Back to a more usualproblem now! At his first

attempt on a computer witha word -processed report,Ted G2HKU in Minster, Isle ofSheppey in Kent, seems tobe holding his own.Meanwhile on air the1.8MHz score includedWOZV, OHO/OH1AF and somerare Europeans.

Nearer home, LeightonSmart GWOLBI in Trelewiskeyed at low power withDL3HWF, SM6LJP, ON4AEB,plus speech with GMOFTX.Leighton's antenna is almosta half -wave mounted at 19metres.

If you're keen on 1.8MHz,the Top Band information neton 14.339MHz is onSaturdays at 1230. You'll findthat SP5INQ and UA9CB0take the chair.

Logs Missing

Mick Holtham GOEIG haswritten in to say his VP8CONlogs went missing in themove from Mount Pleasantin the Falkland Islands.However, they have beenfound and are safely athome.

Immediately he getsback from his currentService duty aboard HMSCoventry, Mick promisesthat the cards will be sentout. Incidentally, he says hisbest contact from theFalklands was with a 2E0using a couple of watts on a'dead' 28MHz band!

SpratlyArguments

There have been pressreports that arguments onsovereignty of the Spratlygroup have come to thesurface. However, mypersonal view is that one lifelost trying to activate Spratlyis one too many!

The 28MHz Band

I've already mentionedVP8CON and his DSO with aBritish Novice on 28MHz.John G3BDQ also found abrief opening which yieldedhim KS4LC and KC4UXM onthe afternoon of January 29.

This month Paul Essery GW3KFE looksto the far south to Antartica for some

important news, provides an informationround -up and your reports.

Coming UpNow for some news ofwhat's coming up. InAugust/September KK6EKhopes to lead an expeditionto Easter Island CEO andSala y Gomez. The latter anew one for IOTA.

In late April/early May anexpedition to Navassa, KC4is on the cards too. Whilethe Big One will be VU2JPS'son Andaman.

If VU2JPS has a gooutside 7MHz s.s.b., he couldbe very busy, Andamanbeing on most people's'Wanted' list. If you get thison time you might catch theConway Reef 3D2 effort;callsign not yet known.

Silent Key

Yet another silent key I'mafraid. One of the Greats ofthe DX world, MartinHaasen 0Y7ML has diedafter a long illness. Apartfrom being a great operator,Martin was a true amateuralways ready to help andadvise anyone thinking of avisit to Faroe.

The 3.5MHz Band

The letter from G2HKUmentions VP2EWW with theOMNI-V, while the low -power IC -721S signal foundits way to severalEuropeans.

There have been someStateside openings notedfrom GW3KFE late at nightbut nothing spectacular.

The 7MHz Band

It was GRP all the way forTed G2HKU on the 3.5MHzband. The results for Tedwere c.w. contacts withS50A and ZA1AJ.

John G3BDQ gave the3.5MHz band a goodpasting on the key. Heworked several JA8s in thefar north of Japan, VKs,KC1XX, ZS6WR, HP1AC,PY1UP/2, RAOFW (SakhalinIsland), VU2RX, andSMOCNS/DU7.

The 14MHz BandOn the other hand 14MHzwasn't G3BDQ's flavour ofthe month. John only wenton to get a c.w. bite fromVP8SGP.

By contrast, the Omni -Vat G2HKU did well. Tedkeyed with VP5FOC, K6NA,N7BG, YV4NX, TI2PZ, PJ9JT,EA6ZY who used to be G3ZY,4X4NJ, VQ9TP, A71CW, a'special' ZS95WRT,VP2EWW and 9H1BM.

The 18MHz Band

For his 18MHz band reportJohn G3BDQ has a goodone this time. Johnmentions sideband contactswith 5NOPYL, CF1YX,

9G5TT, CN2GB, andGMOEKM plus c.w. to 9G1AAand J2OUFT.

Ted's IC -721S at 5W wasenough for G2HKU to dealwith 3B8CF and S51CA. Butthe 'Big Box' was needed forN6AW, TU4SR, VY2SS,ST2AA. He also workedassorted WOs, ZB2E0,A71AN, HK7AAG, andOH1NOAIOD5.

The 21MHz Band

Again on 21MHz it's TedG2HKU who has been busy.Using his Omni -V Tedworked LU4FC, 9J2B0,4X4NJ, EA8AB. He alsomanaged Z23J0 (who is theformer G2S01, TI2PZ, YV4NXand EL2NB

So that's it for thismonth. Keep writing, andenjoy yourself on the h.f.bands! Send your reports toBox 4 Newtown, PowysSY16 122.

ENDPractical Wireless, May 1995 59

Antenna WoiFor many more yearsthan I care to rememberI, like many others, hadaccepted that half -wavedipoles will have a

steady fall in their radiationresistance when they becomecloser to the ground. But onone wet afternoon last summer,when browsing through theARRL Antenna Book (15thEdition), I came across a graphthat showed that this was onlytrue for dipoles above perfectlyconducting ground.

Over what was described as'real' ground, the fall inradiation resistance doesn'thold true. However, the ARRLHandbook definition of 'real'ground is very vague, for in theUK, at least, we have a widerange of soil types.

Perfect ground must beconsidered as being anexcellent conductor in thesame way as copper mesh orsea water. Under thesecircumstances the radiationresistance of a half wave dipolewill fall from about 7052 at aheight of 0.2k down to almostzero at ground.

When 'real' ground is used,there is a remarkable rise inradiation resistance when theantenna height falls below0.05A. This is shown in Fig. 1,which indicates that theradiation resistance will liebetween 50 and 7052 when thedipole is only 0.02 to 0.05kabove real ground.

The rise in radiation

Low Sittig ../mfg7mIs100

90-

80-

70-,

60-,

50-,

40_

30-

20_

10-.

0

Over 'real' ground

Over perfect ground

0.1 0.2 0.3

Height of horizontal i../2 antenna fin wavelengths)

Fig. 1: Graph showing the radiation resistance of half -wave dipoles over a perfect conductor and real ground.The actual curve of the impedance over real ground willvary from location to location, as the soil type varies. Thecurve shown here is only as an illustration andapproximation.

resistance means that a verylow dipole (v.l.d.) for the14MHz band could match into50 or 720 feeder at heights aslow as 500-1000mm. This newinformation created achallenge.

So I set about making apractical v.l.d. for 7MHz. This

was because I thought it mightbe easier to make contacts onthat band.

Garden Canes

I used three one metre (threefoot) garden canes as 'masts'.

A centre support is needed tokeep the middle of the antennaup (against the weight ofcoaxial cable), see Fig. 2. Thininsulated wire was employedto make the dipole and it wascut to resonate on 7.050MHz.

The smallest 'egg' insulatorsI could find were used at thewire ends and a thin rectangleof plastics material served asthe centre connector block.When the coaxial cablereached the ground, it wasburied at right angles to therun of the dipole for a run ofabout five metres.

After the right angled run,the coaxial cable was led intoa boundary hedge and ranback, a distance of about 45m,to the operating position. If thefeeder is not buried (just belowthe surface will do) a balun isneeded to stop r.f. currentsrunning back along the coaxialcable shield.

Half -wave dipoles fed withcoaxial cable present abalance to unbalancesituation. One solution is toslip some 30 or so large ferritebeads over the antenna end ofthe feeder.

The ferrite beads, in effect,form an inductive choke.Suitable ferrite beads may beobtained from Messrs

9.6m for 7MHz4.8m for 14MHz

I^SWate

4

50U coaxial cable runs at rightangle to the antenna (sae text)

Dipole centre piece

Seal all joints and cableentries within this area

9.6m for 7MHz4.8m for 14MHz

Tape the coaxial cableto the support pole

Three non-conductive support poles (such as garden canes) at points A

450-760mm

Insulator

Fig. 2: Practical arrangements for very low dipoles cut for 7 or 14MHz. The three support poles can be made fromalmost any non -conducting material such as garden canes, length of wooden dowelling or plastics material.


irkshoFerromagnetics and arecatalogued as type no: FB-73-2401.

Silicone rubber sealantmust be spread over theconnection end of the coaxialcable. This is to prevent theingress of moisture penetrationand resultant corrosion.

The prototype antenna hadan s.w.r. close to unity and thiswas brought down to exactly1:1 by reducing each dipoleelement by 5%. The v.l.d. wirelengths for 7 and 14MHz areshown in Fig. 2.

First Results

The tirst results of the radiationpattern for a very low dipoleshows mainly high radiationangles. There was little of thevery low angles of radiationwhich are sought after for DXwork.

The radiation pattern maybest be described as a largesphere positioned at the centreof the antenna. There will beconsiderable ground losses(average soil is a poorconductor and a lossydielectric), so much of theradiation will be upwards athigh angles.

An unexpected bonus Ifound with the v.l.d. antenna,is its very low noise level.Signals seem to jump out froma really quiet background. Idid not expect much in theway of performance, but waspleasantly surprised!

I tried both c.w. and s.s.b.transmission in tests on 7MHzand I made many contactswith British and Europeanstations. Reports from thesestations were good, manyreporting an S9 signal. Thetransceiver output for thesetests was 80W and all thestations I worked in the testslay within a 1000km radius.

More Tests

Encouraged by the results on7MHz, I decided to try somemore tests, but this time on14MHz. The dipole wires wereshortened to two 4.8m lengths

and the antenna was loweredto just half a metre aboveground.

The new height of only500mm represents about 0.025of a wavelength. Amazingly,my first tests on 14MHzversion showed an s.w.r. ofunity over the whole of theband. And as with the 7MHztests, I was using just 80W intothe v.l.d.

My first call brought backIK4MFP who gave me a 599report. Many more stationswere worked over the next fewdays including many Russians.

When using s.s.b. modeand I got a 5 -and -9 fromCT3EE. In Uzbekstan, UN8PYLalso gave me 5 -and -9. (On thisband just about everyEuropean country was workedand logged).

In Eastbourne, Eric G3CPS,became interested in myexperiments and quickly madea 'chinese copy' of the 14MHzversion. Eric was amazed withhis results, working all overEurope. Surprisingly, he alsohad c.w. contacts with VE8RAFon Ellesmere Island andA71CW in Quatar.

Eric was as surprised, as Iwas, by the very low noiselevels present. He said that hecould hear exotic DX on theyid. more easily than on hisnormal antennas.

Other Findings

Now for some of my otherfindings .To start I found thatthe yid. antenna worked bestwhen the two dipole wires ranin a straight line.

Secondly, a slight 'dog -leg'on the antenna elements hadlittle effect. But if the anglebetween the wires wasreduced to 120°, there wassome de -tuning.

With the change of tune, Ihad to add a few centimetresto each end of the antenna torestore the antenna to tune.When the wires were broughtto 90° apart, the performancefell right off, the number ofcontacts and incoming reportsdropping.

My yid. antennas are

John Heys G3BDQ questions thesupposed fall in radiation resistance oflow slung antennas. He describes hisexperiments and results using very lowdipoles on th.e 7 and 14MHz bands.

easily and quickly set up andshould be ideal at temporarylocations where outside wiresare frowned upon. But I had tohang little plastics flags on mydipoles to prevent the XYLtripping over the wires!

As mentioned, thedefinition of 'real ground' isvery vague. For example mygarden has a clay loam soilwhereas Eric G3CPS, is onchalk.

More experimenting isneeded with the v.l.d. type ofantenna. This is because theinduction field of a v.I.d.antenna will be absorbed to agreater or lesser degree overlossy ground.

So don't position your lowantenna over your earthsystem. If you do this ofcourse, you will be gettingcloser to the 'perfect ground'of the text books.

In practice, raising orlowering the yid. antennas bysome tens of centimetres hadlittle effect on their s.w.r. Thedipole element lengthshowever, proved to be morecritical.

You can never better a goodantenna system that is half awavelength or more aboveground. But, if for somereason, putting up sky wires isnot possible, a very low dipole

can be tried. It will certainlybring you many contactswithin Europe andoccasionally with stationsfurther afield.

Even if not used fortransmitting, v.I.d.s areexcellent for low noisereception. Man-made noisefields such as those frommotors, thermostats or TV linetimebases are less intense atground level. PW

Further Reading

ARRL Antenna Book 17th Edition. Over 700 pages of manyantennas and related topics.

ARRL Antenna Compendium (Volumes one to three). Threemore ARRL books to make up your library.

HE Antenna Collection (RSGB) edited by Erwin David G4LQI.Extracted from articles previously published in RadCom.

Practical Antennas For Novices (RSGB) by John Heys G3BDQ.Especially written for Novices (or other low power users) to getthe best out of an antenna system.

Practical Wire Antennas (RSGB) by John Heys G3BDQ. Morepractical approaches to wire antennas suitable for manylocations.

All the above books are available through the PW Book Service(see those pages in this issue). In the section marked 'Antennas'(Aerials) you will find many more books that should interestyou.


DAVID BUTLER G4 ASR

I'm going to take a look at the'Propagation Year' this time.This is because I've recentlyreceived a letter asking foradvice about how torecognise when a 'lift' islikely to occur on the v.h.f.bands.

The correspondentmentioned that the only timehe had taken part in suchconditions was more by luckthan judgement. He nowwants to change the odds!

In my view, the key tocatching openings on thev.h.f. bands is based on threesimple processes. These areknowledge, prediction andtact. And now, I'll explain justwhat I mean.

Picking up knowledge ofwhen certain propagationmodes occur is no differentfrom picking up knowledgeof the weather. In the winteryou expect it to be cold andin the summer you hope itwill be hot!

You'll also be aware ofspring showers and autumnfog. And it's exactly thesame with radio propagation.

With a little help you'llsoon learn about summerSp -E, autumnaltroposphericspheric andauroral propagation duringthe equinoxes. But, to helpyou remember them all, I'vedesigned a chart, Fig. 1

The Chart

The chart in Fig. 1 showswhen certain propagationmodes are likely to occurduring the year. The yearplanner shows the fourpropagation modes that aremost common on the v.h.f.bands.

The four modes are:tropospheric enhancementItropol, auroral. Sporadic -E(Sp -E) and meteor scatter(m.s.). Other modes such astropospheric scatter,ionospheric scatter and evenmoonbounce (e.m.e.) exist,but as these require highpower and large antennasystems, I won't mentionthem further.

There are also modesthat only affect the 50MHzband and occasionally the

70MHz band These aretrans -equatorial propagationIt e p I and F2 -layerpropagation. I'll cover theseand the other esoteric modesin a later column.

TroposphericOpeningThe most common of allpropagation modes is thetroposphericsphericopening. Enhancementsoccur throughout the year,usually in the summer.

However, the bestopenings are in the autumnduring the months of Octoberand November. Openings inthe summer can occur at anytime of the day or night butare generally better in theearly morning or evening.

The reasons for betterevening and morning eventsare straightforward. It'sbecause the cause of thesurface duct, thetemperature inversion, isdestroyed to some extent bythe warming rays of the sun.

Tropo enhancement canbe found on all bands from144MHz through into themicrowave region. Althoughsmall lifts are experiencedon the 50 and 70MHz bands,they are never extensive.

Auroral Openings

Auroral openings also occurat any time of the year, butpeak around the equinoxes.So I suggest you keep aspecial watch duringFebruary -March andOctober -November.

Openings normally occurbetween 1400-1900UTC andaround local midnight. Allevents are different but thepeak times for DX is usually1500-1700UTC.

Auroral propagationworks best on the 50 and70MHz bands. However,much activity can also befound on the 144MHz bandbecause of the increasedinternational availability.Contacts on the 430MHzband are more scarce andusually limited to the largerauroral events.

This month David Butler G4ASR explainsjust how you can catch those elusive

openings on the v.h.f. and u.h.f. bands.David gives advice by looking at the

'Propagation Year' and provides a specialchart.

Sporadic -E

Openings via Sp -Epropagation occur frequentlyduring the summer months.On the lower frequency v.h.f.bands the season will start inearly May and continue intothe first week or so ofAugust.

There's also a winterpeak in activity duringDecember -January. The50MHz band can often beopen for DX at some timebetween 0600-2400UTC.

More intense openingscreate openings on the144MHz band, normallyduring June and July.

The upper frequencylimit of Sp -E propagation isaround 230MHz. The besttimes to catch openings onthis band are 1000-1400 and1600-2000UTC.

Meteor ScatterPropagation via the ionisedtrails of meteors las theyburn up in the upperatmosphere) exists everysingle day of the yearallowing contacts to bemade with stations up to2000km away. However,many m.s. enthusiasts preferto operate during majormeteor showers when thechances of making acomplete QSO are greatlyenhanced.

The principal showersoccur virtually every monthof the year. But the months ofFebruary, March andSeptember are theexception. In the northernhemisphere most showersoccur in the months May -August.

The great thing aboutm.s. is that unlike otherpropagation modes, the'opening' can be predictedwith a high degree ofconfidence. And contactswith low power and simpleantennas are very easy tomake on the 50MHz band.

You'll need about 100Wand a reasonably long Yagi tomake consistent contacts onthe 144MHz band. But onlystations with e.m.e.capability should attempt

contacts on the 430MHzband!

The Knowledge

So, the knowledge is the firstof the three essentialprocesses. It will tell you ingeneral terms whensomething is likely tohappen.

To narrow the odds stillfurther you need to have amethod of predicting theopening. This is our secondprocess and once again I'lluse the analogy of weatheras it draws a usefulcomparison.

Study of existing weatherpatterns and knowledge oftrends enables themeteorological office toissue accurate forecasts. Allyou need do then is watchthe weather report to get agood idea what will happenduring the next few days.Similarly a study of variouspropagation events(Yes...even on the h.f. bands!)will give you clues when thenext v.h.f. opening mightOccur.

UsualMechanismInterestingly, the most usualmechanism that governsday-to-day band conditionshas its origins in the weather.Tropospheric propagation islinked to the fundamentalproperties of theatmosphere.

The properties are,incidentally, the verticaldistribution of temperatureand water vapour. Thesetropospheric lifts occur mostoften in anticyclonic weathersystems. Watch out for anarea of high pressure duringthe summer when yourbarometer is reading Fair orVery Dry.

During the autumn, someexcellenttroposphericspheric DX canbe worked when the weatherconditions are misty. So,keep a look out for weatherforecasts where fog or mistis indicated and highpressure extends from the


UK deep into Europe.It's also a good idea to

watch for co -channelinterference (c.c.i.) on TVtoo. This can be a pointer toa lift' (particularly on430MHz) on v.h.f./u.h.f. Onyour TV, c.c.i. shows up aseither fine horizontal lines or(when the lift is pronounced)a complete foreign televisionpicture.

ImportantCalendarI've mentioned many times inthis column the importantneed to keep a 27 -dayauroral calendar. This issimply a chart of the year (orlonger periods) displayed in27 -day strips.

Whenever an auroralopening is observed youshould note it on the chart.As the sun takesapproximately 27 days torotate it's possible that arepeat may occur a monthlater. And although youwon't catch every repeatevent it will indicate whenspecial attention should bepaid to the band.

There are also a numberof reliable indicators whichgive a short-term indicationof auroral events. Forexample, some 20 to 40hours before a radio aurora,incoming high energyelectrons may penetratedown into the ionospheric D,E or F layer regions.

The incoming highenergy electrons can causeh.f. fade-outs. So, if yourfavourite h.f. band (or I.f.band for that matter) isacting strangely it's worthremembering that an auroramight occur within a day orso.

One of the most reliableshort-term indicators ofauroral events isdisturbances caused to theearth's magnetic field. Youcan detect them with amagnetometer using a Hall -effect sensor, which issimple to build and gives anexcellent indication ofauroral openings.

Not Restricted

The use of a 27 -day calendaris not just restricted toauroral prediction. The chartcan also show when theactive or quiet side of thesun is facing the earth.

The 'active' or 'quiet'indication is very useful asthe sun has a considerableinfluence on otherpropagation modes. This isespecially true of the 50MHzband when F2 -layerpropagation is prevalent.

Some 'experts' also

claim to be able to predictwhen Sp -E openings aremost probable. Certainly inmy experience the formationof Sp -E seems to be inhibitedduring periods of auroralactivity.

So, although many otherfactors need to be taken intoaccount, periods when thegeomagnetic K -index is 0 or1 (little or no activity) isconducive to Sp -E openings.You'll need to listen to thestandard WWV broadcastsor propagation beacons likeDKOWCY (10.144MHz) to getthis information.Alternatively the DX Clusternetwork can provide thisdata.

Regular Intervals

Earlier I mentioned thatmeteor showers occur atregular intervals. And ofcourse they do!

However, it's worthnoting that by keeping arecord of the previous year'sactivity an accurateprediction of subsequentradio peaks can be made.This is because the earthintercepts the shower orbitevery 365.25 days.

So, by simply adding sixhours to the date and time ofthe previous year's radiopeak, you can predict fairlyaccurately when the peakwill be this year. For leapyears, you must subtract oneday for all shower datesafter February 29.

For example, I noticedthat conditions during thePerseids shower last yearseemed to peak between0900-1200UTC on August 12.There was also another peakin activity between 2200-0400UTC during theevening.

Therefore, the radio peakof the Perseids meteorshower this year will bebetween 1500-1800 onSaturday August 12 andbetween 0400-1000UTC onSunday August 13. But ofcourse, these predictionswon't guarantee that anymeteors will be present atthe time!

Another way to makepredictions of meteorshower peaks is to useappropriate software and acomputer. Incidentally, aprogram by OH5IY gives thePerseids peak as 113OUTCon August 12, with anaccuracy of ±3 hours.

Yet another predictionprogram, this version is byG4PMK, gives the peak as0115UTC on August 13.However, which method youuse is your choice but I canguarantee that there will bemuch DX activity thatweekend!

MaintainingRecordsSo, the second process, thatof prediction, is simply amatter of maintainingrecords of solar or weatherdriven events. Of course it'snot quite as simple as that,but after a while you'll get anintuitive feel for yourfavourite band.

Finally I'll turn to the lastof our processes. This isprobably the most importantand deals with what'shappening right now.

Again I'll compare radioconditions with the weather.For example, if you stick yourhead out of the window andit gets wet you can say it'sraining!

Next turn the radio on.You hear lots of DX. Theband's open! Nothing can bea substitute for actuallysitting in the shack andlistening to the v.h.f. bands. Ifyou did it all day long youwouldn't miss a thing.

However, as I've justdescribed you don't actuallyneed to monitor the bands allthe time...only when it's morelikely to be open. But Irealise that not everyone canafford the time to sit in theshack tuning aimlessly upand down the frequencybands.

One method I use,

particularly for Sp -E andauroral propagation, is tomonitor activity in the 48-54MHz region This spectrumcovers not only the 50MHzamateur band but also BandI television broadcaststations.

The Band I televisiontransmitters are especiallyuseful 'indicators' as asufficient number of themstill exist throughout Europe.Additionally, radio aurorasand Sp -E are more prevalentat these low frequenciesthan the 144MHz band forexample.

By investing in a 50MHzconverter and a simpledipole you are able tomonitor Band I. You couldalso get a few hours warningof better things to come onhigher frequencies.

Good Results

Two other real-timeinformation methods alsogive good results. The first isthe use of the DX Clusternetwork.

By logging into your localcluster you are able tomonitor DX spotted by otherstations. The attraction ofthis packet radio basedsystem is that you can set upparameters to your particularliking. You could, forexample, configure the

system to alert you onlywhen DX spots areannounced for the 50 or144MHz band.

The other method is toform a telephone 'warningchain'. This is quite easy toset up but does rely on otherpeople telephoning you.More often than not theyprefer to stay on themicrophone and work theDX!

Finally, if all else fails justleave your radio tuned to28.885, 50.110, or 144.3MHz orwhatever calling frequencyyou prefer and turn thevolume up. You can then dothe washing up and monitorthe band at the same time!

Deadline Time

It's deadline time again! And,by the time you read this, thefirst signs of the summer Sp -E season should beobserved.

So, if you make anyinteresting contacts pleaselet me know about it. Asusual send your reports tome at: Yew Tree Cottage,Lower Maescoed,Herefordshire HR2 OHP or viapacket radio @ GB7MAD orthe DX Cluster system.Alternatively you cantelephone me on (01873)87679.

E N D

Fig. 1:Propagationmodes chart byG4ASR (see text).

Recommended Reading

The VHF/UHF DX Book by Ian White G3SEKt (ISBN 0-9520468-0-6).Radio Auroras by Charlie Newton G2FKZ (ISBN 1-872309-03-8).Space Radio Handbook by John Branegan GM4IHJt(ISBN 1-872309-05-4).Beyond Line of Sight by Emil Pocock W3EP (ISBN087259-402-5)

t Available from the PW Book Service


PETER SHORE

Since the beginning of April,Britain's internationalbroadcaster, BBC WorldService (WS), has beentransmitting five differentversions of its Englishlanguage output. Regionalschedules have beendevised which, according toWS Managing Director, SamYounger, "put time on thelistener's side", with thesame programmes beingbroadcast, but at moreconvenient times.

Apparently in someparts of the world, up untilnow, tuning to things likePlay of the Week meantgetting up before sunrise, orlistening in the middle of thenight. Now, wherever youmay be in the world 'yourfavourite programmes areat times to suit you'. A boldclaim from the world's mostlistened to internationalradio station, but what doesit mean in practice?

Five separate 'streams'of programmes are nowleaving Bush House on theirway to transmitting stationsin Britain and overseasrelays. One streambroadcasts to Europe, NorthAfrica and the Middle East,as well as most of thecountries that formed theSoviet Union; another goesto Africa south of theSahara; South Asia (India,Pakistan, Bangladesh,Nepal) receive another;Asia and the Pacific has itsown service; and theAmericas, from the wastesof the Canadian north tothe tip of the SouthAmerican continent hasanother.

So, if you tune in to15.07MHz, a favouriteEuropean frequency, youshould hear the WorldService's European service.Try 15.40MHz fromAscension, and you'll getthe African stream,complete with Focus onAfrica and otherprogrammes made foraudiences in the continent.And so on, all around theworld.

But what about strangefrequencies like 6.195MHz?In the European earlyevening the 6.195MHz has

often been subject to an otfputting echo as thefrequency is broadcastfrom the UK and anoverseas stationsimultaneously.

Under the newscheme, the twotransmitters might carryseparate programmes, andeffectively the BBC wouldjam itself. Apparently thenew schedule has ironedout such problems. Let meknow if you spot anystrange effects caused bythe World Service's newbroadcasting techniques.

Radio Metropolis

There's been quite a lot ofreaction to my mention lastmonth of new Czech shortwave broadcaster, RadioMetropolis. Robin Guppy inBasildon, Essex, and A. P.Oldroyd in Ossett, WestYorkshire, were among thefirst to write and say theyhad heard the station.

Robin caught thestation in February using anewly purchased KenwoodR-5000. It's connected to a25 metre long-wire antenna.

The set owned by A. P.Oldroyd is a Sony SW -55. Heuses the set's built-in whipantenna and says he alsopicked up Radio NewZealand International verywell on it. Radio Metropoliswas heard on 5.905MHz at114OUTC on February 20.

Keep writing, and don'tjust limit your news tosnippets about RadioMetropolis!

Columbia'sServiceReports have been carriedon a number of DX showson the short wave bandsabout the re-emergence ofColombia's internationalservice. Radio Nacional hasbeen logged between 2230and 0000UTC on 4.955MHz,with identification inSpanish. The station'saddress is RadiodifusoraNacional de Colombia,Radio Canal Internacional,PO Box 93994, Bogota

In this month's round -up. Peter Shore hasnews of changes to the BBC World

Service, readers' reports as well as thelatest radio programme schedules.

Latest SchedulesA new schedule has recentlyarrived from Radio Budapest.From the end of March, thestation will be on the air withEnglish to Europe at 2000until 2030 on 3.975, 6.11 and7.22MHz, and at 2200 to 2230on 3.955, 6.11 and 7.22MHz.The North America service ison the air for 30 minutes at0200 on 6.025, 9.0835 and11.91MHz and at 0330 on5.965, 9.835 and 11.91MHz.

Radio Budapest haspublished its 'Honours List'for 1994. The list containsdetails of people whoparticipated in Budapest'sprogrammes during the year,with letters quoted,questions answered, orsuggestions for broadcastfeatures sent in. There are 21listeners in the UK (includingone who slipped in althoughhis addresswho are included on the list,and 18 from the USA.

Contact the station tosee if you can make it intothe 1995 Honours List. Thestation's address is RadioBudapest, Brody Sander u. 5-7, H-1800 Budapest, Hungary,or FAX on +36 1 138 8838 or138 8517. There is also ananswering machineconnected to +36 1 138 8320.

The Voice of Greece hasEnglish for Europe at thefollowing times: 0740 on11.645, 9.935 and 9.425MHz;1335 on 17.52, 15.65MHz; 1910on 9.38, 6.26MHz

The Voice of the IslamicRepublic of Iran beamsEnglish worldwide at: 0030on 9.67, 9.022 and 7.10MHz toNorth America; 1130 on11.93, 11.79 and 11.745MHz tothe Middle East and Asia;1530 on 11.79 and 9.575MHzto Asia; 1930 on 9.022 and7.26MHz to Europe andAfrica. All programmes areone hour long.

The Iranian station hasstarted a new Swahiliservice to East Africa. It hasbeen observed on the air at1700UTC for half -an -hour on11.74 and 9.685MHz.

Vietnam has started touse transmitters in Russia tobeam into Europe. There isan English service at 0400 fortwo hours on 5.94MHz, and

at 0600UTC an hour longprogramme in Spanish istransmitted on 7.40MHz,following a Voice of Russia(formerly Radio Moscow)Spanish service programme.

Christian Science

The sale of the Scott'sCorner transmitting stationbuilt by the World Service o'the Christian ScienceMonitor has now beencompleted. The ChristianScience Monitor has sold thefully operational site to theWorld Voice of HistoricAdventism for USS5million.

The Monitor hasconcentrated its US shortwave operation to theCypress Creek site in SouthCarolina. From there it beamsto Europe and Africa using500kW transmitters.

China Messenger

The winter edition of ChinaRadio International's (CRI)The Messenger landed onmy desk just as I wasfinishing off this month'scolumn. The stationpublishes its Englishlanguage schedule as: 2000-2200 on 9.92 and 6.95MHz toEurope direct from China;2200-2230 on 3.985MHz fromSwitzerland and 2200-2300on 7.17MHz from a Russiantransmitter. Can anyoneexplain why CRI broadcaststwo distinct programmes tothe same target area at thesame time?

Broadcasts to NorthAmerica's East Coast are at0000 on 9.71 and 11.715MHzfrom Mali; 0300-0400 on 9.69from Spain; 9.71 and11.715MHz both from Mali;0400-0600 on 9.73 fromFrench Guiana.

That's all for this month. Dokeep writing to me via thePWEditorial Offices withdetails of interesting thingsyou've caught. Until nexttime, good listening.

END64 Practical Wireless, May 1995

R OGER COOK E G3LDIRoger Cooke G3LDI

brings you news of his tripto Australia, where he made a

point of meeting many amateursinterested in packet. This month Roger

introduces just a few of the more (retire stations.

During my Australian tour Istayed in Crowsnest, asuburb of Sydney with JohnBayes VK2SB and his wifeMary. John and I had planneda trip north up the coast ofAustralia, as far as Cairns, inNorthern Queensland.We had the TS -50 in the carwith a home-made whip onthe roof and also a 144MHzf.m. rig, so we were well-equipped radio -wise.Unfortunately, propagationdid not favour us too well andwe spent most of our time on144MHz or the VK travellersnet on 14.116MHz.

One of the first amateurswe spoke with was JimVK2FJM. Jim is a white stickoperator and wanted to knowif there was a method ofgetting onto packet. I thoughtI had seen a mention of thissomewhere, so if anybodycan enlighten me, I would bedelighted to pass anyinformation back to Jim.

Further north in PortMacquarie, John and I spokewith Richard VK2CHC. Wewere invited to visit PeterVK2BZA, who at 80 plus, stillworks DX regularly.

Further north still, wevisited Paul VK2BZC, who hasa superb location on a hill -topand is very active on packet.

Paul is a Doctor and isknown locally as Dr. Paul onthe air! He is featured in Fig.1. Paul is only active on thev.h.f./u.h.f. bands.

One of the more well-known Port Macquariepacket people must be TonyLonsdale VK2DHU, the authorof PAKET, the packet terminalprogram. We got lost on theway to Tony, but eventuallyfound him, and he is shown atthe terminal in Fig. 2.

Tony very kindly gave us acopy of PAKET 6 - which atthe time was the latestversion of his software. Wespent a very informativeevening with him.

No Site Clearance

One very nice thing about VKis that there is no siteclearance, no special BBSlicence, so there's no need towait. They just operate!

However, even without an

Fig. 1: (Right) PaulVK2BZC in his compact

shack.

official organisation, they stillmanage to run quite anefficient network, which mustbe extremely difficultconsidering the enormousdistances involved.

The packet 'backbone' ison u.h.f. at 1200baud,

although changing to9k6baud shortly with users on144MHz. Tony estimated thatout of 50 amateurs rn PortMaquarie, about 12 wereactive on packet.

The Australian AmateurPacket Radio Association(AAPRA) is a very active anddedicated organisation whichhas some 250 memoers. Wevisited Jo Harris VK2KAA,one of AAPRA's committeemembers on our return toSydney.

More on Jo in my nextcolumn. However, Jo waskind enough to let me have acopy of the PAKET Handbook,produced by AAPRA.

The PAKET Handbook is avery nicely produced manual,telling you just abouteverything you need to knowabout the computer programPAKET. The book, written byTony VK2DHU, is availablefrom AAPRA for S30 seamailor $35 airmail. It is wellbound, starts with an indexand is separated into 11 partsor chapters.

The handbook starts withthe history and description ofthe Australian Network,before describing startingPAKET. There are sections onREMOTE mode, SCRIPTPROCESSING and PMS

system. There's a sectiondealing with PAKETPROTOCOL and a Technicalsection which givesinformation on handshakingand TNC settings.

Written with two columnsper page, the book has a stylecatering for the raw beginner,but is still excellent for themore advanced user. Runningto around 150 pages, it's goodvalue and seems a must forthe PAKET user. It can beobtained from:

AAPRA, 59 WestbrookAvenue, Wahroonga, NSW2076, Australia.

By this time, all the talkabout packet had inspiredJohn. He was thinking howbest to get onto the modeupon our return to Sydney, sohe also took a copy of PAKETfrom Tony and made it hisproject before I left for home!

John wondered if he wasgetting too old at 64 to getinto the digital world, so wevisited Bob VK2AWA, who, at

Fig. 2: (Left)Tony LonsdaleVK2DHU theauthor of thePAKET computerprogram.

Fig. 3: (Below)John VK2AWAwho at 78 yearsyoung, showsyou're never tooold to enjoyyourself onpacket radio.

78 years young I his words!is active on packet andthoroughly enjoys it. Bob livesin Coffs Harbour and ispictured in Fig. 3 proves you'renever too old to have fun!

BBS SurvivalGuide

Finally, I would just like to saythat the BBS Survival Guide,2nd Edition, is now available.It now runs to 98 pages, butwith different livery, with alight blue cover, and loadsmore information. The cost is£6.00 post paid from G3LDI orit is available from SiskinElectronics. Profits will go tothe Amsat Phase3D fund.

Happy Packeting. Roger,G3LDI GB7LDI, or QTHR for'snailmail'. Tel: (01508) 570278

ENDPractical Wireless, May 1995

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We will always try to help readers having difficulties with Practical Wirelessprojects, 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, tocommercial radio, TV or electronic equipment.3: All letters asking for advice must be accompanied by a stamped self-addressed envelope lor envelope plus IRCs for overseas readers).4: Make sure you describe the problem adequately, with as much detail asyou can possibly supply.5: Only one problem per letter please.

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Constructional ProjectsComponents for PW projects are usually readily available from componentsuppliers. For unusual or specialised components, a source or sources willbe quoted.Each constructional project is given a rating to guide readers as to thecomplexity.Beginner: A project that can be tackled by a beginner who is able to identifycomponents and handle a soldering iron.Intermediate: A fair degree of experience of building radio or electronicprojects is assumed, but only basic test equipment will be needed tocomplete any tests and adjustments.Advanced: A project likely to appeal to the experienced constructor. Accessto workshop facilities and test equipment will often be required. Definitelynot for the beginner to attempt without assistance.

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Are you frightenedof computers andintimidated by allthe jargon? Well,

this month'sPractical WirelessSubs Club special

offer could changeall that. You canlearn to use andenjoy computer

technology to yourbest advantage and

get PW deliveredto your door into

the bargain'

&clime is

As we've got a 'Computing in Radio' theme this month, I've lookedat various books on the subject with the aim of helping readerswho (like me!) are somewhat intimidated by computer technology.And without hesitation I'm again recommending PCs Made Easy(2nd Edition), as an effective answer to all those 'computer knowails' we're surrounded with in the office and our hobby!

Armed with PC's Made Easy, you, like me, can become morefamiliar with personal computers. Remember, a computer is just asophisticated tool, it need not become a way of life for anyone, youjust use it to your advantage. Computers are there to serve you, notthe other way round and PCs Made Easy takes the mystique out ofthe subject.

With chapters entitled: Getting Started, What Can A Computer DoFor Me?, What Are All These Parts?, What's A Program, How Do IPrint?, What's A Network?, you'll soon realise PCs Made Easy isaimed at helping you. However, although the hook is aimed athelping the beginner, it also provides a good reference source forestablished users. And personally speaking, I've found the bookvery helpful in setting up my younger daughter's PC requirementsand questions for College. (The chapters Do's & Don'ts and BuyingA Computer were especially helpful here!)

I especially recommend this book. It helped me and I think itcould help you too!

G3XFD

You can get your copy of PCs Made Easy for £13.95 plus £1P&P (UK), £1.75 P&P (overseas) (normal price £15.93 plus£1 P&P UK and £1.75 P&P overseas) and get PWdeliveredto your door every month too!

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To take advantage of this offer just fill inthe details on the order form on page 68 of

this issue. Alternatively call Ann orMichael on our Credit Card Hotline on(01202) 659930 and quote SCPW5 to

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Advertisements from traders, or for equipment that is illegal to possess, use or which cannotbe licensed in the UK, will not be accepted. No responsibility will be taken for errors.

For Sale

Attention Irish readers: KenwoodTS -50, as new, £749. Alinco DJ580with accessories, £349. AlincoDR112E 144MHz mobile, £225.A0R3000 mint, £575. MFJ949E 300Wa.t.u., £129. Opto 3300 frequencycounter, £129. Everything is boxedand in as new condition. GaryEI3EUB, Ireland. Tel: 051-71278.

FT -290R plus Diawa LA2035 linearamp, s.w.r./power meter. DRAEwavemeter, mobile (car) mountingbracket, 1/2 wave whip, bits andbobs, £250 o.n.o. Geoff Munn, Essex.Tel: (01279) 861371.

FT -470 dual bander, extendedcoverage, two batteries with newcells, soft case, manual, boxed,£270. Yaesu BC29 fast charger,boxed, £40. Sony AIR 7 scanner150.2194kHz, 76-174MHz, manual,£120. Pye F412 u.h.f. base station,f70. F9U u.h.f. base station, £45 J. PHarston GW4JQP. Tel: (01269)597367.

FT -707 with c.w. filter, FP707 powersupply, FC707 a.t.u., stand, mic., mintmobile mount and manuals, £550.Geoff G4ECF, Surrey. Tel: 101483)570033.

FT -736R 144/430MHz with muTekfront end, as new, £1000. 1C726 100Wh.f. plus 10W 50MHz, as new, £650.IC211E 144MHz multi -mode basewith muTek front end, £325. FT290Mkl mag mount Heatherlite, etc.,£210. Simon G4TVR, Solihull. Tel:0121-745 8222.

High current power supply 15/30V at45A d.c. unregulated, could bemodified to give 15V at 90A, f95 orswap for AV0160 valves tester. Tel:Buckinghamshire (01494) 521531.

Icom IC -725 plus f.m., manual, £560.Midland 4001, converted 29FM, £45.Reace RC1000 transceivermonitoring system,s.w.r./p.o.w./m.o.d., 1kW rated, £45.All excellent condition, all inc.delivery. Barry GORZI, Cumbria. Tel:(01946) 812092.

!corn IC -R70, excellent conditionwith original packaging, manuals,etc., silent key sale, £325. Tel:Bracknell (01344) 426161.


Kenwood TS830M unmodified in anyway, with built-in p.s.u., full manualand circuit diagrams, £450 for quicksale. Pete, Essex. Tel: 101206) 395968evenings after 6.30pm.

KW2000E with power supply, KWEZEE match, KW s.w.r. meter 101,v.g.c. Tiny Tim QRP rigs 3.5/1.8MHz,these two need slight attention.Offers. Tel: S. Yorks (013021859451.

MFJ-207 h.f./s.w.r. analyser, 1.75-30MHz, as new, boxed withinstructions. Checks antennaresonance, adjusts antenna tuner,£75. CapCo SPC-300D a.t.u., co-ax/balanced outputs, 1kW p.e.p., 1-30MHz, as new, boxed withinstructions, £200. G2FZU,Nottinghamshire. Tel: 101636) 813847.No offers please.

Practical Wireless back issues,1949-1965, some years complete,some not. Reasonable condition,offers. Tel: Newcastle 0191-281 7995.

Practical Wireless magazines,1951-93, some complete years, alsoEveryday Electronics, PracticalElectronics, Radio ElectronicsConstructor. T. Robinson, Rugeley.Tel: (01889) 583965.

Quantity of OST, T+R, Bulletins 30-70-s, CO, SWM 1940-70s, MelodyMaker cabinet, 1930s. W1117wavemeter, Hallicrafters S2OR RX.All v.g.c., delivery Midlandspossible, sell or swap. Tel: (01938)810938.

RAE 3 hour video tape, five books,question and answer manual, mathsand physics, etc., RAE Manual andHow To Pass The RAE. I've passed!£12 plus postage. Vic, Cornwall. Tel:101579) 348127.

RU19 aircraft radio, two coil packs,2-7MHz, good condition, f25. Tel:Essex 1017021522929.

Scanner, hand-held, Maruhama RT-618 all -mode wide band scanningreceiver, 0.5 to 1300MHz, continuouscoverage f.m.w., f.m.n., a.m. ands.s.b. modes, 800 programmablememories, £230 o.n.o. Tel:Chippenham (01249) 658025.

Silent key sale: YaesuTS820 (ht.), £325. TS227R

BargainBasement

May1995

144MHz mobile, £90 with 5amppower supply, FT -411R 144MHzhand-held, £90. Kenwood antennatuner, £150. Realistic PRO -43 hand-held scanner, £150. Mr Elliott on(01222) 495477 after 6pm.

Standard C58 144MHz matching25W linear, p.s.u., mobile mount,mint condition, all manuals, £275.Wyse dumb terminal, £30. Tworotators, £50 and £30. Or the lot forgood reflector telescope. Tony,Herts. Tel: (01923) 681800 eveningsor (01956) 808391 days.

TS -430S h.f. plus FTV-250 28/144MHztransverter, £550. Linear two144MHz s.s.b., 10W, £65. Yaesu FR -5013 Ham bands receiver, £60.Belcom LS -102 28MHz multi -mode10W, £140. R1475 RX, no p.s.u., £40.Ben, Worcs. Tel: (01562) 743253.

Two Compaq XT -PCs plus wealth ofspares Iso no split), £250. Mustcollect! Yaesu FRG7700M plusFRT7700, £350. BBC/RTTY system,£160. (RTTY alone £50). Diablo p.s.u.15V -8A, £10. Tel: 0161-477 5303. Orsend an s.a.e. for full shackclearance lists to: K. Burrows, 10Basil Street, Stockport, CheshireSK4 1QL

Wendel and Golterman PS20 levelgenerator, 20Hz to 20kHz plus 10dBto 59.9dB. Separate receive andtransmit units, £150 each Tel: NorthLondon 0171-263 6068 evenings.

WWII collectors: W.T. Mkl Morsekey, dated 1940, in steel case withDLR No. 5 headphones and No. 3carbon microphone with leads andplugs, all in first class condition, £20per set. Peter, Aberdeenshire. Tel:(017711623654.

Yaesu FT -290R multi -modetransceiver, including rechargeablebatteries, charger, hands free mic.,case, carrying strap, etc., excellentcondition, £210. Charles Smart,Stourbridge. Tel: (01562) 883257.

Yaesu FT -707, extra 600Hz filter.YM36-mic., power lead, handbook,mint, £375. Trio TR2300 f.m. withmic., case/strap, NiCads (new),charger, handbook, mint, £135.Drake T4XC R4C MS4/AC4 leads,manuals, mint, £800. Tel: Dover(01304) 373101.

Exchange

AOR 3000A scanner, seven monthsold hence mint condition, boxedwith manual, offered in exchangefor Kenwood R5000 or similar.

Reason for exchange,now own two scanners.Tel: Isle of Wight 1019831756533.

Icom R7100 wanted in exchange formy 486 DX2/66 computer systemwith laser printer, may accept R7000or AOR3000A. Chris, Essex. Tel:(01376) 561670

Kenwood TM742E 50W f.m. dualband transceiver and KenwoodTM255E 40W 144MHz multimodetransceiver, both current modelswith detachable fronts, etc., willexchange both for Kenwood TS790Ebase station transceiver. B.Williams, W. Yorkshire. Tel: 1012741880895.

Wanted

Data on KW201 amateur receiver,please advise. Also really goodEddystone 830/7 receiver. JohnG3CUN, West Midlands. Tel: 0121-474 4856.

Datong converter UC1, anyinformation on Timestep frequencymeter (digital) dial DFC41 and Zetagifrequency counter C50. TonyWoodward, Worcester. Tel: (019051641759 before 2100 please.

Early Sony products like TR-55,TR-72 and TR-63 radios, TV8-301 TVset, CV -200 video recorder, TPS-C2walkman, FD -200 flat tube TV,CDP-101 CD player, BVW-IBetacam camera, BCM-100Betamovie camera, CCD-V8 8mmvideo camera, D-50 portable CDplayer. Enrico Tedeschi, 54 EasthillDrive, Portslade, Brighton BN41 2FD.Tel/FAX: (01273) 410749 or mobile(08501 104725.

Sony CRF1/2001D H.E.C. CG -R700,Panasonic RF 9000/8000/B-600.Philips AL990, Hitachi KH 3800,speaker/memory for JRC5I5. Sale oftrade. Sony 320, Philips 22RL793(broken), Somm/KP FR DX500.Please write to Sabino Fina, 83042,Atripalda (Av), Italy.

SSTV scan converter, Robot, etc.,must be functional. Tel: Liverpool0151-531 1305.

TCS-6 transmitter in clean condition.David Fletcher, Cambridge. Tel:(01223) 843408.

Vintage or modern military gearWWII/NAM, etc., receivers,transmitters, UK/USA/Europe, willcollect within reason or paypostage. Ben, Worcs. Tel: 101562)743253

Wireless World, Vol. 31 (July toDecember 1932) and Vol. 46 11940).Terry Brown G4TZB, Manchester.Tel: 0161-643 6116

69

Classified AdsTo advertise on this page see hooking form below.

Educational

COURSE FOR CITY AND GUILDS Radio AmateursExamination. Pass this important examination andobtain your licence, with an RRC Home Study Course.For details of this and other courses (GCSE, career andprofessional examinations, etcl write or phone - THERAPID RESULTS COLLEGE, DEPT JX116, TuitionHouse, London SW19 4DS. Tel: 0181-947 727219am-5pm) or use our 24hr Recordacall service0181-946 1102 quoting JX116.

HEATHKIT EDUCATIONAL PRODUCTS UKDISTRIBUTOR/SPARES AND SERVICE CENTRE.Cedar Electronics. 12 Ishourne Way, Broadway Road.Winchcombe, Cheltenham. Glos. GL54 5NS.Tel: 1012421 602402.

RAE"The Video"The definitive learning

aid for the exam! A full

three hour VHS video

based on the highly

successful training

course developed and

presented by

Chris Budd GOLOJ

This unbeatable package comes

complete with a detailed course

study booklet, packed with key

learning points, facts and

diagrams for instant reference

and easy revision. Only £22.50

plus £2 postage and pocking or

available to callers.

Send cheque or postal order to:

Tricorn Marketing ltd,31 Berkeley Square,

Bristol 858 1HPTel: 0117-921 5390

Wanted

WANTED FOR CASH Valve or solid statecommunication receivers Pre -1980. Preferably workingand in good condition. Non working sets consideredalso domestic valve radios. Items of Governmentsurplus wireless equipment and obsolete testequipment. Pre -1965 wireless and audio componentsand accessories. Pre -1975 wireless and TV books andmagazines. Also, most valves wanted for cash. Must beunused and boxed. CBS, 157 Dickson Road, Blackpool,FY1 2EU. Tel: 1012531 751858 or Fax: 101253) 302979.

WANTED FERRITE ROD AREIALS must be half inch in diameter no more or less. Must be six incheslong or more. contact Peter Tankard on Sheffield0114-234 3030 any time.

For Sale

VINTAGE SERVICE DATA, circuits & manuals - for:HiFi, Military, Radio, Television & car radio up to the1060's. Free brochure. Savoy Hill Publications, "SevenAsh Cottage", Seven Ash, Combe Martin, NorthDevon. E X34 OPA Tel: 1012711 882665.

LANDHEHR VHF/UHF masthead preamplifiers 2

metre 145MAS £147 and 70cm 435MA £152 P&P £4.Write or phone for leaflet. Ouatiles Radio 23 Dark Lane.Hollywood, Birmingham B47 5BS. Tel: 0121-430 7267.

Valves

VALVES GALORE Most valves available from stock.Otherwise obtained quickly. Please send SAE statingrequirements or telephone. VALVE & ELECTRONICSUPPUES Chevet Books, 157 Dickson Road,Blackpool FY1 2EU.Tel: 1012531751858 or Fax: 1012531 302979.

WANTED, VALVES GZ34, KT66, K688, PX4, PX25and all West European/USA manufactured audiovalves. Please post list of what you have available forprompt reply. We also wholesale audio tubes, valvesand CRTs. Mimimum order £100. Billington Export, 1EGillmans Ind Est, Billingshurst RH14 9EZ. Phone: 01403784961 Fax: 01403 783519. Callers strictly byappointment only please

SCIENTIFICSHAREWARE

Discover the true wealth of PO and shareware for the PC. Since 1982

PDSL have supplied the best and latest programs covering all

interests.

Business, Leisure, Engineering. CAD. DTP. Maths, Stats. Chemistry,

Education. Electronics, Ham Radio. Esoteric, Medical. Raytracing,

Programming & languages. Tools, Utilities, WP. Editors, Comms.

Special applications, Esoteric, Novelty, Astronomy & hundreds more.

All software can be provided on floppy disc or CD ROM

Whatever your interested in we probably have Send today for our PC

Shareware reference guide It runs to more than 250.000 words and is

probably the most comprehensive catalogue currently available

Send f250 (voucher provided refundable on first order) orF4X Access V sa kfC'n

PDSL,WinscombeHouse,BeaconRoad,Crowborough, EastSussexTN61UL.

Tel (01892)663298

FAX.1018921667413

Whilst prices of goods shown in advertisements are

correct at the time of going to press, readers are

advised to check both prices and availability of

goods with the advertiser before ordering from

non -current issues of the magazine.

DISCLAIMERSome of the products offered for sale in

advertisements in this magazine may have beenobtained from abroad or from unauthorised sources.Practical Wireless advises readers contemplatingmail order to enquire whether the products aresuitable for use in the UK and have full after -salesback-up available.The publishers of Practical Wireless wish to pointout that it is the responsibility of readers to ascertainthe legality or otherwise of items offered for sale byadvertisers in this magazine.

ComputerSoftware & Hardware

ULTIMATE MORSE TUTOR for PC's and ATARI £30rom BOSCAD Ltd, 16 Aytoun Grove, Baldridgeburn,

Dunfermline, Fife KY12 9TA or Tel: 01383 729584,evenings for detailed information.JVFAX/SSTV, Hamcomm, Pktmon. 9FD or 25FDPC Transceive Interface, Programmes, Manuals,Pictures. £25.50. G8SLB IQTHRI.Tel: 0181-595 0823.

Receivers

B.F.O. KITS Resolves single side -band on almost anyradio, £16.49. H. CORRIGAN, 7 York Street, Ayr KA8 8AR.

Miscellaneous

DIY INEXPENSIVE RADIO PROJECTS. Easy tomake, SAE, RYLANDS, 39 Parkside Avenue,Southampton S01 9AF.

VALVE ENTHUSIASTS: Capacitors and otherparts At attractive prices' Ring for free list. GeoffDavies (Radio), Tel: 1017881 574774.

TOP PRICES PAIDfor all your valves, tubes,semi -conductors and ICs.

Langrex Supplies Ltd.,1 Mayo Road, Croydon,

Surrey CR0 2RP.Tr t 0181-684 1166. FAX: 0181-684 3056.

ORDER FORM FOR CLASSIFIED ADS PLEASE WRITE IN BLOCK CAPITALSThe prepaid rate for classified advertisements is 42 pence per word (minimum 12 words), box number 70p extra. Semi -display setting £13.90 persingle column centimetre (minimum 2.5cm). Please add 17.5% VAT to the total. All cheques, postal orders, etc., to be made payable to the PWPublishing. Treasury notes should always be sent by registered post. Advertisements, together with remittance should be sent to the ClassifiedAdvertisement Dept., Practical Wireless, Arrowsmith Court, Station Approach, Broadstone, Dorset BH18 8PW. Tel: 1012021659920, Fax:(012021 659950

Please insert this advertisement in the ,,,,,,, issue of Practical Wireless (if you do not specify an issue wewill insert it in the next available issue of PW) for12 minimum, please add 17.5% VAT to total).

Name'

Address:

Telephone No

Box Number @ 70p: Tick if appropriate

Category heading:

insertion/s. I enclose Cheque/P.O. for E )42p per word,


ISSUE ONSALE

NOW

ADVERTISEMENT AGENTREQUIRED

THE RADIO SOCIETY OF GREAT BRITAIN seeks to appoint anindependent advertisement agent to handle the advertising spacein its publications, principally the magazine Radio Communication.

Radio Communication is the UK's leading title targeting thelicensed radio amateur. Published monthly and circulated to 31.000members, it is a 100 -page. A4 colour production carrying onaverage 30% of content as display and classified advertising pages.

Applications are sought solely from prospective agents withrelevant experience and capability. It will be a significant advantageto be the holder of a current amateur radio licence or to have apractical knowledge of electronics terminology. This is not anopportunity to learn on the tob!

The agency responsibilities will include:1 Marketing of the space to the trade and agencies.2 Production work, technical copy writing, layout and typography

for trade setting or with own DTP system.

3 Page make-up, proofing. classifieds and setting -house liaison.4 Administration of orders, schedules, charging out (via RSGB).5 Provision of professional advice to the Society and an impartial

complaints service to members and advertisers.The agent will act independently on all routine matters but will be

contracted as an agent in law. Remuneration will be by commissiononly. Applications will be considered from established professionalsand those with the experience who may choose to take thisopportunity to open a new and suitably financed venture.

Applications should be made in writing with an outline of relevantprofessional experience and supporting facilities. Total confidentialitywill be observed. Marking your letter 'CONFIDENTIAL' please writeto the General Manager at:

Radio Society of Great BritainLambda House, Cranborne Road, Potters Bar, Herts EN6 3JE

ELECTRONICSVALVES& SEMICONDUCTORSWe are one of the largest stockists

COLOMOR (ELECTRONICS) LTD.

Phone for amost courteous quotation

081-743 0899Fax: 081-749 3934

of valves etc, in the U.K.170 GOLDHAWK ROAL)

LONDON W12 8HJ

TRANSVERTERS, LINEAR AMPLIFIERS,PREAMPS, TRANSMIT TONES & MORE.

IN KIT OR READY BUILT FORM.Also Community Broadcast Equipment for Restricted Service Use.

SEND SAE OR 2IRC's FOR CATALOGUESPECTRUM COMMUNICATIONSUNIT 6B FOUNDBURY WEST ESTATE, DORCHESTER.

DORSET DTI 2PG Phone and FAX 01305 262250OPENING TIMES 91.2-5 TUE FRI 9-1 SAT. Cl OSED SUN d MON 10I

YAESU, ICOM, AOR etc.SALES & SERVICE Holdings of Blackburn Ltd. Inc. 1952. Yoe.) Agents

since 1972 GALL 40 -I -years in electronics. Best prices for callers (try uswith cheque or 'real money' if you want to bargain) only xyl and self to

pay so we can afford to give good prices - valves and CW filtersFor old Yoesu eg Phone, normally open Tues. Wed. Fri and SatLunch 12 00-1 -30 but phone first we enjoy a few holidays,

G3111 HOLDINGS, AMATEUR ELECTRONICS45 JOHNSTON STREET, BLACKBURN, 11B2 lEF

10254159595

- Create Your Own Circuit Diagrams !With this new Multi -Tasking PCB Editor for DOS PC's with standard Autoroutes up to

6 layers for an all -in -one excellent pica -quality offer

Build your own components. diagrams. frontplates. etc. with the professional andincredible program Lots of HAM schematics as samples available

For more information or a demo -package please contact:

FRL Electronic Systems. PO Box 37154. 1030 AD Arnsterdam.The NetherlandsTeLFax: + 31 20 6342740 or Internet FRLOinter.NLnet

THE KITS WITH ALL THE BITSSend an SAE for a comprehensive list of kits

Or call Alan on 01 I 5-938 2509

LAKE ELECTRONICS7 Middleton Close, Nuthall, Nottingham NG 16 I BX

Ir7 (Callers by appointment only)

SHORT WAVE MAGAZINEti Must for the Serious listener

CF)WIPER AIWA SPECIAL

444"444 ,ILIOE OWL WOW pf.11A

PR/L "Va"M"1110Y 11,1

el MO

Irrrr -":=.- -

VOWION

411.111,111101111

1;1.;1 'WA?

IN THIS MONTH'S BUMPERAIRBAND SPECIAL

REVIEWED: ALSO:

HOWES AB118 ANTENNA A AIRCRAFT RADIO EQUIPMENTSELDEC SELCALL DECODER ,s( THE HAMSTER - THE

ULTIMATE ACCESORY?

A A 747 FLIGHT - FROM THECOCKPIT

: CALLS SECALLS & SOAWKS: RADIO SECRETS OF THE WAR

PART 2

OFFERS:

NiCads and ChargerAirband Active Antenna

PLUS ALL OUR REGULAR FEATURES!

Coming Next Month inthe Decode Special

Reviewed - Wavecom

W4100 Data Analyser

Decoding Interfaces -

Getting Started

,` Build - A Super Regen VHF

Receiver

The Internet and the SWL

Beginners Guide to RTTY

A How to Choose a Receiver

for Data Reception

Books and CD Roms for

the Decode Listener

Sets in Conflict - VE Day

Commemoration


BOKSERI

..1 ....-1--1

- -- --

r-I

DJP2A'ilFor every book

order received betweenApril 13 1995 and May 10 1995, thename and address of the customerwill beentered into our prize draw

for this issue. OnMay 11 one name will be pulled from the sack.The luckyperson will win a £50 note (the genuinearticle!). So why not order that book or booksYou've been thinking about, you could well be ourlucky winner

next time, don't forget it's muchshorter odds than the National Lottery!

The books listed have been selected as being of special interest to our readers.They are supplied direct to your door. Many titles are overseas in origin.

TO ORDER:PLEASE USE THE ORDER FORM ON PAGE 68 OR TELEPHONE THE CREDITCARD HOTLINE ON (01202) 659930.

LISTENINGGUIDESCALLSIGN 95The Civil & Military Aviation CallsignDirectoryIntended for the aircraft and radioenthusiast to use as a stand alonereference, or as a partner to Airwaves 94.Over 5300 military and 3000 civil callsignsare covered in detail. 108 pages. E7.95

AIRWAVES 94The Complete HF/VHF/UHF AviationFrequency DirectoryMuch of the more obscure 'especiallymilitary) information is made accessible inthis volume. Not only are facilities/activitieslisted, giving their frequencies, but alsothere are reverse lists - when the frequencyis known, the allocated user can be found.Airways sectors are listed so much moreclearly than in the Supplements. The maintransponder code groups are included. Infact, the book covers all the way from h.f. upto u.h.f.88 pages. £7.95

AIR BAND RADIO HANDBOOK5th EditionDavid J. SmithAir band radio listening enables you tolisten -in on the conversations betweenaircraft and those on the ground whocontrol them, and is an increasingly popularand fascinating hobby. A new chapter onmilitary air band has been added. Theauthor, an air traffic controller, explainsmore about this listening hobby.190 pages £8.99

THE COMPLETE SHORT WAVE LISTENER'SHANDBOOK 4th EDITIONHank Bennett, Harry Helms

David HardyThis book is a comprehensive guide to thebasics of short wave listening. Everythingyou need to get started as an s.w.l. isexplained in a clear and easily understoodmanner. Receivers, antennas, frequencies.propagation, Id -codes, etc are all covered.321 pages. E17.95

FERRELUS CONFIDENTIAL FREQUENCYLIST 9th EditionCompiled by Geoff HalligeySpirally bound, this easy -to -use referencebook covers 1 6 - 28MHz in great depth, allmodes and utility services, with newreverse frequency listing showing everyknown frequency against each callsign,who's using what frequency and mode,what's that callsign?544 pages E17.95

SCANNER BUSTERSD C. PooleThis guise to the methodology of beatingthe electronic ban on Scanning, deals withthe subject of scrambling and encryptionsystems. The author explains in simpleterms how p.m.r. works, the new digitalcellular radio telephone systems, spreadspectrum, frequency hopping and

to get more from your scanner and a list offrequencies to listen to are also covered. Itis a great reference for both new scannerowners and veterans alike.64 pages. E4.95

SCANNING SECRETSMark FrancisThe miseries of monitoring explained.Advice on buying and operating yourscanner. Where to listen and how to gatherobscure frequencies. The myths and folklore exposed All the information need tounlock the potential of your scanner.280 pages. £16.95

FLIGHT ROUTINGS 1994Compiled by T.T. & S.J. WilliamsThis guide was produced with the sole aimof assisting airband listeners to quickly finddetails of a flight, once they have identifiedan aircraft's callsign. Identifies the flights ofairlines, schedule, charter, cargo and mail,to and from the UK and Eire and overflightsbetween Europe and America122 pages. 0/P

GUIDE TO FAX RADIO STATIONS14th EditionJoerg KlingenfussThe new edition of this super referencebook covers the world's facsimile stations,their frequencies and methods of working.There is a section covenng the equipmentneeded to receive FAX over the radio. Togive you an idea of what is available thereare many pages of off -air received FAXpictures 392 pages. E20.00

GUIDE TO UTILITY STATIONS13th EditionJoerg KlingenfussThis book covers the complete short waverange from 3 to 30MHz together with theadjacent frequency bands from 0 to 150kHzand from 1.6 to 3MHz. It includes details onall types of utility stations including FAX andRTTY. There are 19549 entries in thefrequency list and 3590 in the alphabeticalcallsign list plus press services andmeteorological stations. Included are RTTY

& FAX press and meteo schedules Thereare 11800 changes since the lath edition.534 pages E30.00

INTERNATIONAL RADIO STATIONS GUIDEBP355Peter ShoreAs in 'Broadcast Round -up', his column inPIN. Peter Shore has laid this book out inworld areas, providing the listener with areference work designed to guide aroundthe ever -more complex radio bands. Thereare sections covering English languagetransmissions, programmes for DXers ands.w.l.s. Along with sections on Europeanmedium wave and UK f. m stations266 pages. £5.95

POCKET GUIDE TO RTTY AND FAXSTATIONSBill Lever

FAX stations, together with modes and otheressential information The listing is inascending frequency order, from 1.6 to26.8M Hz. 57 pages £3.95

RADIO LISTENERS GUIDE 1995Clive WoodyeerThis is the third edition of this radio

listener's guide.Simple -to -usemaps and chartsshow thefrequencies forradio stations inthe UK.Organised sothat the variousstation types arelisted separately,the maps areuseful for thetravellinglistener. Articles

included in the guide discuss v.h.f. aerials,ROS, the Radio Authority and developmentsfrom Blaupunkt. 68 pages. E3.45

411i

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SHORT WAVE INTERNATIONALFREQUENCY GUIDEThis book contains a comprehensivefrequency listing covering 400kHz - 30MHzand is packed with everything from thebasics of short wave listening to explainingFAX and RTTY In this updated version thereare many new broadcast and utilitystations listed 188 pages E12.95

UK SCANNING DIRECTORY4th EditionThis spiral bound book lists over 20000 UKspot frequencies from 25MHz to 1.6GHz.Articles on scanning in the UK.335 pages. E17.50

WORLD RADIO TV HANDBOOK 1995Country -by -country listing of I.w., m w &s.w broadcast and TV stations Receivertest reports, English language broadcasts.The s.w.l.'s 'bible .

E15.95

SATELLITESNEWNES GUIDE TO SATELLITE TVDerek StephensonThis book, the 3rd edition, is a hard boundvolume, printed on high quality paper. Theauthor is a satellite repair and installationengineer and the book covers all informationneeded by the installation engineer, thehobbyist and the service engineer tounderstand the theoretical and practicalaspects of satellite reception with dishinstallation and how to trouble -shoot whenpicture quality is not up to anticipatedreception. Mathematics has been kept to aminimum.371 pages. £18.95

SATELLITE BOOK A Complete Guide toSatellite TV Theory and PracticeJohn BreedsThis book deals almost exclusively withtelevision broadcast satellites and is acomprehensive collection of chapters ontopics, each written by a expert in that field.It appears to be aimed at the professionalsatellite system installer, for whom it isinvaluable, but it will be appreciated by amuch wider audience anyone interested insatellite technology.280 pages. E32.00

SATELLITE EXPERIMENTER'S HANDBOOK2nd EditionMartin Davidoff K2UBCThe book is divided into four main sections -History. Getting Started, Technical Topics andAppendices. It provides information onspacecraft built by, and for, radio amateurs. Inaddition, it discusses weather, TV -broadcastand other satellites of interest to amateurs.313 pages E14.50

SATELLITE TELEVISIONA layman's guidePeter PearsonPictures from space, that's what satellitetelevision is all about. Orbiting satellites.35000km high, receive TV signals fromstations on the earth and re -transmit themback again This book explains all you needto know to set up your own satellite TVterminal at home, dish and accessories,cable and tuner.73 pages. £1.00

SATELLITE TELEVISION INSTALLATIONGUIDE5th EditionJohn BreedsA practical guide to satellite television.Detailed guide -lines on installing and aligningdishes based on practical experience.76 pages £15.00

WEATHER SATELLITE HANDBOOK5th EditionDr Ralph E. Taggart WB8DQTThis 000k explains all about weathersatellites, how they work and how you canreceive and decode their signals to providethe fascinating pictures of the world'sweather. Plenty of circuit diagrams andsatellite predicting programs.192 pages £14.50

WRTH SATELLITE BROADCASTING GUIDE1994 Edition. Bart KuperusThis brand new publication, written by one ofthe experts from the respected World RadioTV Handbook, will be a great help toeveryone interested in the world of satelliteradio and television. Featuring over 300pictures and graphics. All the information youneed to know about installing your ownsatellite system366 pages. E15.95


AMATEURRADIOALL ABOUT VHF AMATEUR RADIOW I. Orr W6SAIWritten in nontechnical language, this bookprovides information covering important aspectsof v h f radio and tells you where you can findadditional data. If you have a scanner, you'll find alot of interesting signals in the huge span offrequencies covered, 100300MHz & 50, 420, 902 &1250MHz bands 163 pages E9.50

AMATEUR RADIO CALLBOOK & INFORMATIONDIRECTORY IRSGBILatest EditionThe first 124 pages provide a useful informationdirectory with details of specialised clubs,county lists, repeater details, band plans andreference material Then follows the callbookitself with over 60 000 callsigns including El andNovice stations. A new section has been addedtowards the back of the book giving lists ofsurnames and initials of listed radio amteursfollowed by callsigns and the same under post-code areas508 pages 0/P

AMATEUR RADIO FOR BEGINNERS RSGBVictor Brand G3JNB

An ideal book for theabsolute beginner to theamateur radio hobby. Weliillustrated and aninteresting read65 Pages £3.50

AMATEUR RADIOLOGBOOKPublished by RSGBThis standard spirallybound amateur radio logbook has 100 pages and is

marked out with the format required in the UKThere are columns for date, time (UTC),frequency, power lin d8W), stationworked/called, reports, QSL information andremarks. 02.99

AMATEUR RADIO TECHNIQUES RSGBPat Hawker G3VAAnyone who enjoys Pat Hawker's TechnicalTopics' in Radio Communications will enjoy thisbook An amateur radio manual itself, thispaperback book, the 7th edition, can only bebettered by a new edition. A truly excellentreference source with a practical bias368 pages E1.50

ANTENNAS AND TECHNIQUES FOR LOWBAND DOING IARRLIJohn Devoldere °NOUNThis unusual book will be of particular interest to113, 3.5 and 7MHz operators as it's packed withinformation on antennas and operating tips for'Top Band to Forty' fans. There are chapters onlow band propagation, operating techniques,equipment and for the computer minded there'sa chapter on newly -available low bandsoftware393 pages E14.50

ARAL HANDBOOK FOR RADIO AMATEURS 1995This is the 72nd edition of this nandhook andcontains the best information from previousissues New for this edition is some informationon feedback -loop design for power supplies, anew gel -cell charger project, updates on antennasystems and new coverage of baluns,propagation programs are compared and colourSSTV and telephone FAX machines are alsocovered. Finally there's a new section on 'for theworkbench' with new projects for the reader tobuild7214 pages E19.95

ARAL OPERATING MANUALAnother very useful ARRL book Although writtenfor the American amateur, this book will also be ofuse and interest to the UK amateur. Topicscovered range from short wave listening throughoperating awards to repeaters, operating andsatellites684 pages E12.95

ARRL SATELLITE ANTHOLOGYThe best from the Amateur Satellite News columnand articles out of 31 issues of OSThave beengathered together in this book. The latestinformation on OSCARs 9 through 13 as well asthe RS satellites is included. Operation on Phase 3satellites (OSCAR 10 and 131 is covered in detail97 pages E5.95

ARRL UHF/MICROWAVE EXPERIMENTER'SMANUALVarious AuthorsA truly excellent manual for the keen microwaveenthusiast and for the budding 'microwaver'With contributions from over 20 specialistauthors Chapters covering techniques, theory,projects, methods and mathematics446 pages E14.50

THE BRIGHT SPARKS OF WIRELESS RSGBG. R. Jessop G6JPThis hardback book is well illustrated with someexcellent photographs. It pays tribute to and takes

a good look at the personalities behind the earlydays of amateur radio and the equipment theyused A good read 90 pages. E12.50

COMPLETE EIXERBob LocherThis book covers equipment and operatingtechniques for the DX chaser, from beginner toadvanced. Every significant aspect of OXing iscovered, from learning how to really listen, howto snatch the rare ones out of the pile-ups andhow to secure that elusive QSL card 204 pagesE7.95

HINTS AND KINKS FOR THE RADIO AMATEUREdited by CharlesL Hutchinson andDavid NewkirkA collection ofpractical ideasgleaned from thepages of (1STmagazine Plentyof protects tobuild, hints andbps oninterference, cw.and operating andsnippets ofinformation fromamateurs who'vetried and testedthe idea129 pages. E4.95

Hints * KinksWIWI TM MALMO 11.1"110

HOW TO PASS THE RADIO AMATEURS'EXAMINATION IRSGBIClive Smith G4FZH and George Benbow G3HBThe background to multiple choice exams andhow to study for them with sample RAE paper forpractice plus maths revision and how to study forthe exam. The majority of this book is given tosample examination papers so that candidatescan familiarise themselves with the examinationand assess their abilfty.88 pages E7.99

INTRODUCTION TO AMATEURCOMMUNICATIONS SATELLITESBPZ90 . A. PickardThis book describes several currently availablesystems, their connection to an appropriatecomputer and how they can be operated withsuitable software. The results of decoding signalscontaining such information as telemetry dataand weather pictures are demonstrated 102pages £3.95

INTRODUCTION TO AMATEUR RADIO BP257I. D. PooleThis book gives the newcomer a comprehensiveand easy to understand guide through amateurradio. Topics include operating procedures.organ, propagation and setting up a station. 150pages £3.50

INTRODUCTION TO RADIO WAVE PROPAGATIONBP293J.G. LeeHow does the sun and sunspots affect thepropagation of the radio waves which are thebasis of our hobby? They affect the ionosphere,but differing frequencies are treated differently.Find out how to use charts to predict frequenciesthat will be the most profitable. What effect willnoise have on the signal? Find out with this book716 pages E3.95

INTRODUCTION TO VHF/UHF FOR RADIOAMATEURS B P261I.D. PooleAn excellent book to go with the new Novice orfull callsign. Nine chapters and an appendix dealwith all aspects and frequencies from 50 to1300MHz Topics include propagation,descriptions of the bands, antennas, receivers,transmitters and a special chapter on scanners,102 pages E3.50

LOW PROFILE AMATEUR RADIO - OPERATING AHAM STATION FROM ALMOST ANYWHEREJim Kearman KRISThis book delves into to the techniques of being a'hidden Ham- There are chapters on specialisedequipment. operating techniques and antennas toname but a few. If you have a fascination for spytype radio equipment or like the idea of having acomplete h f or yhf. rig built in a suitcase, thenthis little American book is for you 124 pagesE5.95

MICROWAVE HANDBOOK RSGBVolumes 1.2 and 3Edited By M. W. Dixon G3PFRApproximately 350 pages (each volume) Vol 1

costs E9.99, Vol 2 and 3 cost E14.99 each

PRACTICAL GUIDE TO PACKET OPERATION INTHE UKMike Mansfield G6AWDIntroduces the concept of packet radio to thebeginner Problem areas are discussed andsuggestions made for solutions to minimise themDeals with the technical aspects of packet takingthe reader through setting up and provides acomprehensive guide to essential referencematerial 220 pages E9.95

QRP CLASSICSEdited by Bob SchetgenOperating GRP is fun The equipment is generally

simple and easy to build, but often performs likemore sophisticated commercial equipment.Some GRP Field Day stations operate a full 27hours on a car battery it's the perfect equipmentfor emergency communication when the powerfails Extracts from OST and the ARRL Handbook,274 pages £9.95

RADIO AMATEUR CALLBOOK INTERNATIONALUSTINGS 199573rd EditionThe only publication listing licensed radioamateurs throughout the world. Also includesDXCC Countries list, standard time chart. beaconlists and much more Over 1400 pages £20.95

RADIO AMATEUR CALLBOOK NORTH AMERICANUSTINGS 199573rd EditionListings of US amateurs lincluding Hawaii) Alsocontains standard time chart, census of amateurlicences of the world, world-wide QSL bureau.etc Over 1400 pages. E20.95

THE RADIO AMATEUR'S GUIDE TO EMC RSGBRobin Page -Jones G3JWIThis paperback book provides essentialinformation and reading for anyone who has anEMC linterferencel problem. With the help of thewell -illustrated text and techniques, much of themystery from the troublesome world ofelectromagnetic compatibility is removed177 pages. E7.99

RADIO COMMUNICATION HANDBOOK IRSGBI6th EditionDick Biddulph G8POSThis long awaited new edition has beenextensively up -dated and is full of diagrams andphotographs. This book is a completehandbook/reference work and project book allrolled into one. The final innovation is that thenecessary p c b templates for the featuredprojects are provided at the end of the bookmaking them much easier to work from whenmaking your own p c b.s. 750 pages. E20.00.

RAE MANUAL RSGBG.LBenbow G3HBThe latest edition of the standard aid to studyingfor the Radio Amateurs' Examination. Updated tocover the latest revisions to the syllabus Takesthe candidate step-by-step through the course727 pages 0799

RAE REVISION NOTESGeorge Benbow G3HBIf you're studying for the Radio Amateur's Exam -nation, this book could be useful It's a summaryof the salient points of the Radio Amateurs'Examination Manual, the standard textbook forthe exam It's A5 size and therefore can be carriedwith you wherever you go. Easy -to -read, it'sdivided into 13 chapters with topics like receivers,power supplies, measurements, operatingprocedures, licence conditions and a summary ofthe formulae all dealt with 92 pages. E4.99

REVISION QUESTIONS FORThe Novice RAE RSGBEsde Tyler GOAECIn effect Esde Tyler's book could be considered asbeing a training manual for the NRAE Answersare supplied and the book provides a usefulreference source 60 pages BOO

RECEIVING STATION LOG BOOKPublished by RSGBE3 50

SPACE RADIO HANDBOOK RSGBJohn Branegan GM4IHJ236 E12.50

THE NOVICE LICENCE STUDENT'SNOTEBOOKJohn Case GW4HWRThis is the recommended course book foranyone taking the Novice Licence. Covering allaspects of amateur radio and electronics itwould be useful to anyone starting out inamateur radio. Every left hand page is for yourown notes of explanation124 pages. E5.99

TRAINING FOR THENOVICE LICENCE RSGBJohn Case GW4HWRAimed at the Novicelicence instructor thismanual provides thesyllabus and an excellentframework textbook tohelp novice, instructor andbeginner alike Anexcellent basic referencework 101 pages E6.50

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VHF/UHF DX BOOKEdited Ian White G3SEKAn all round source o' inspiration for the

h f enthusiast. Written by acknowledgedexperts this book covers just about everything youneed to know about the technicalities ofv h.f./u h.f operating 210 pages nue

VHF UHF MANUAL RSGBG. R. Jessop G6JPThe 4th edition of this well known book is inpaperback form Packed with information for the

world of radio above 30MHz It covers everythingfrom v.h fluh f radio history and theory andpropagation to protects and techniques. Anexcellent reference source.Approximately 1000 pages E10.50

W1FIls DESIGN NOTEBOOKDoug DeMAW W1FBThis book is aimed at the non -technical amateurwho wants to build simple projects and obtain abasic understanding of amateur electronics. Yourworkshop does not need to be equipped like anengineering lab to be successful as anexperimenter Don't let a lack of test equipmentkeep you from enjoying the thrills ofexperimentation 195 pages. £8.50

WIFE'S HELP FOR NEW HAMSDoug DeMaw W1FBThis book covers everything from gettingacquainted with new equipment to constructingantennas, station layout, interference andoperating problems to on -the -air conduct andprocedures 155 pages 03.95

WIFB's ORP NOTEBOOK2nd Edition. Doug De Maw W1FBThe new improved and updated 2nd edition of thisbook, covers the introduction to GRP, constructionmethods, receivers and transmitters for CIRP. Thisworkshop -notebook style publication, which ispacked with new designs for the keen GRPoperator, also covers techniques, accessoriesand has a small technical reference section175 pages E7.95

WORLD AT THEIR FINGERTIPS RSGBJohn Clarncoats G6CL 307 pages E6.00

YOUR GATEWAY TO PACKET RADIOStan Homes WA1LOUWhat is packet radio good for and what uses doesit have for the average' amateur? What areprotocols? where, why, when? Lots of the mostasked questions are answered in this useful book.It included details of networking and spaceCommunications using packet 218 pages E8.95

YOUR PACKET COMPANIONSteve Ford WBBIMYThis American book goes to considerable lengthsto explain in simple terms how the radio amateurcan get going on packet, how it works and whatthe various systems are There are chaptersdealing with assembling a packet station, sendingand receiving packet mail and exploringadvanced networking systems. Your PackerCompanion goes a long way to explain some ofthe mysteries of packet radio. 170 pages E5.95

DATAREFERENCENEWNES AUDIO & HI-FI ENGINEER'S POCKETBOOKVivian CapelMows Hardback E10.95

NEWNES COMPUTER ENGINEER'S POCKETBOOK255 pages. Hardback. E12.95

POWER SELECTOR GUIDE BP235J. C. J. Van de Ven160 pages 14 95

NEWNES ELECTRONICS ENGINEERSPOCKET BOOK1st EditionKeith BrindleyThis fact -filled pocket book will prove useful forany electronics engineer. Its comprehensivecoverage includes literally everything fromelectronic physics to abbreviations, informationon integrated circuits, applications. componentdata, circuits and systems In effect this bookprovides a very useful portable electronicsreference source 305 pages. E12.95

A REFERENCE GUIDE TO BASIC ELECTRONICSTERMS BP286F. A. WilsonCovering everything from Amplitude Modulationto Zener Diodes, this excellent guide is a manual,dictionary and revrsion book all rolled into one.With concise explanations, clear diagrams andeasy to follow examples, this is an essentialaddition to the library of anyone contemplatingtaking the RAE 414 pages. E5.95

A REFERENCE GUIDE TO PRACTICALELECTRONICS TERMS BP2B7F. A. WilsonThis is a well written clearly illustrated referenceguide which. when used on its own, is perhaps ofmore use to those interested in the contructionalside of amateur radio However, it is of particularbenefit to those taking the RAE especially d usedin conjunction with A Reference Guide to BasicElectronics Terms 442 pages f5.95

INTERNATIONAL TRANSISTOREQUIVALENTS GUIDE BP85Adrian Michaels300 pages 13.95


CONSTRUCTIONCIRCUIT SOURCE BOOK 2 BP322R. A Penfold 214 pages £4.95

COIL DESIGN AND CONTRUCTION MANUALBPI60

Babani ?ribcages £2.50

G-ORP CLUB CIRCUIT HANDBOOKEdited by Rev. G. Dobbs G3RJVThis paperback book has been compiled fromcircuits published in the G-ORP Club puma!Sprat from the years 1974 to 1982. Essentially it'sa collection of circuits and projects coveringeverything from receivers, transmitters,antennas and accessories together with sedORP test equipment. This book is aimed at thekeen constructor and provides all theinformation required to build the host of proiactsdescribed.96 pages 0.50

HOW TO DESIGN AND MAKE YOUR OWN PCBsBPIZI R. A. PenfoldThe purpose of this book is to familiarise thereader with both simple end more sophisticatedmethods of producing p.c.b.s. The emphasis ofthe book is very much on the practical aspectsof p.c.b design and construction 66 pages.E2_50

MORE ADVANCED POWER SUPPLY PROJECTSBMW R. A. PenfoldThe practical and theoretical aspects of thecircuits are covered in some detail Topicsinclude switched mode power supplies,precision regulators, dual tracking regulatorsand computer controlled power supplies. etc. 92pages. £2.95

PROJECTS FOR RADIO AMATEURS AND SWLSBP304 R. A. PenfoldThis small book covers the construction and useof radio frequency and intermediate frequency

projects, and audio frequency projects. Underthe first heading ideas include a crystalcalibrator, an antenna tuning unit. a wave trap, ab.f o. and other useful projects. On the audioside projects include a bandpess filter, a by-passswitch, a c.w./RTTY decoder and many otherpractical ideas and suggestions for the homeconstructor.92 pages. 0.95

POWER SUPPLY PROJECTS BP76R. A. PenfoldThis book gives a number of power supplydesigns including simple unstabilised types,fixed voltage regulated types and variablevoltage stabilised designs.89 pages. E2.50

SHORT WAVE SUPERHET RECEIVERCONSTRUCTION BP276R.A. PenfoldA general purpose receiver to build, fromantenna to audio. described in understandableEnglish. 80 pages £2.95

TEST EQUIPMENT CONSTRUCTIONBP248. R.A.PenfoldDescribes, vi detail, how to construct somesimple and inexpensive, but extremely useful,pieces of test equipment. Shipboard layouts areprovided far ell designs, together with wiringdiagrams where appropriate, plus notes on theirconstruction and use 104 pages 0.95

50 (HT) FIELD EFFECT TRANSISTOR PROJECTSBP39F.G.Rayer50 circuits for the s w I., radio amateur,experimenter or audio enthusiast using Lets.Projects include r.f. amplifiers and converters,test equipment and receiver aids, tuners,receivers, mixers and tone controls.104 pages. E2.95

BEGINNERSELECTRONICS SIMPUFIED - CRYSTAL SET CONSTRUCTIONBP92 F. A. WilsonEspecially written for those who wish to take part in basic radio building. All the sets in the book are olddesigns updated with modern components. It is designed for all ages upwards from the day when onecan read intelligently and handle simple tools72 pages. 0.75

RADIOTHE WORLDWIDE AERONAUTICALCOMMUNICATIONS FREQUENCY DIRECTORY 2ndEditionRobert E. EvansThis book covers aeronautical radiocommunications, voice and digital, within therange of h.f. and v.h frequency bands.Commercial, military and pare -military operationsare included. Divided into logical sections, itprovides useful infomation and frequencies onalmost anything and everything airband.260 pages 0955

UNDERSTANDING ACARS 2nd EditionAircraft Communications Addressing andReporting SystemEd FlynnHere is tiro intormation you need to understandand decode the Aircraft CommunicationsAddressing and Reporting System, otherwiseknown as ACARS. Deals with the equipmentneeded as well as message format and type80 pages 0.95

AIR II METEO CODE MANUAL 14th Edition.Joerg KlingentussDetailed descriptions of the World MeteorologicalOrganisation Global Telecommunication Systemoperating FAX and RTTY meteo stations, and itsmessage format with decoding examples Alsodetailed description of the Aeronautical FixedTelecommunication Network amongst others.358 pages £20.00

HIGH POWER WIRELESS EQUIPMENTArticles from Practical Electricity 1910 -1911Edited by Henry Walter Young305 pages 17 70

MARINE SSB OPERATIONJ. Michael GaleHow do you stay in touch when you sail off overthe horizon and into the blue? What you need is asingle sideband radio, a marine ss.b. This bookexplains how the system works. how to chooseand install your set and how to get the best out ofit. There is also a chapter on amateur radio withthe emphasis on the increasingly importantmaritime mobile nets. %pages £10.95

MARINE VHF OPERATIONJ. Michael GaleA v.h.f radiotelephone is essential equipment forany seagoing boat, but what can you do withWho can you call, and how do you make contact?Which channel do you use, and why? What is theprocedure for calling another boat, calling thefamily through the telephone system. or making adistress call' This book will tell you.47 pages. £7.95

PASSPORT TO WORLD BAND RADIO 1995This book gives you the information to explore andenvoy the world of broadcast band listening It

includes features on different international radio

stations. receiver reviews and advice as well asthe hours and language of oroadcast stations byfrequency. The 'blue pages' provide a channel -to.channel guide to world bard schedules.416 pages £14.50

RADIOTELETYPE CODE MANUAL 13th EditionJoerg KlingenfussThis book gives detailed descriptions of thecharacteristics of telegraph transmission on shortwaves, with all commercial modulation typesincluding voice frequency telegraphy andcomprehensive information on all RTTY systemsand cw. alphabets. 96 pages £14.00

AN INTRODUCTION TO SCANNERS ANDSCANNING BP311L D. PooleThis boos is ideal for anyone wanting to knowwhat scanning is, and how it works. There are alsochapters on radio in general, covering antennas,radio waves and how they travel, types oftransmissions, broadcasting and amateur radio. Allin all a superb starter book. 152 pages. £4.95

SCANNERS 2Peter Rouse GUlDKOThe companion to Scanners, this provides evenmore information on the use of the v.h.f. and u.h.fcommunications band and gives constructionaldetails for accessories to improve the perform-ance of scanning equipment 261 pages E10.95

SCANNERS 3 PUTTING SCANNERS INTOPRACTICE. New Edition 4th RevisionPeter RouseThe title Scanners 3has been chosen to avoidconfusion, as the book has undergone a virtualrewrite since Scanners 3rd Edition was published.Although written by the late Peter Rouse. ChrisLorek G4HCL has edited and 'finished off' this. thelatest in the Scanners series. Including frequencylists, and for the first time, a section on the h.f.bands. Also listed are full British bandplans from 25to 2000MHz, as well as a section on scanner andaccessory dealers 271 pages £9.95

SHORT WAVE COMMUNICATIONSPeter Rouse G U 1 OKOCovers a very wide area and so provides an idealintroduction to the hobby of radio commsInternational frequency listings for aviation,marine, military. space launches, search andrescue, etc. Chapters on basic radio propagation,how to work your radio and what the controls do,antennas and band plans. 187 pages £1.95

WORLDWIDE HE RADIO HANDBOOKMartyr R Cooke 124 ;:ages E6.95

1934 OFFICIAL SHORT WAVE RADIO MANUALEdited by Hugo GernsbackA fascinating reprint from a bygone age with adirectory of all the 1934 s w receivers, servicinginformation, constructional projects, circuits andideas on building vintage radio sets with modernpens. 260 pages £11.60

COMPUTINGINTERFACING PCs AND COMPATIBLES BP212R A Penfold8e ,e44te, E3.95

ELECTRONIC PROJECTS FOR YOUR PC BP320R. A. Penfold102 pac, E3.95

INTRODUCTION TO COMPUTERCOMMUNICATIONS IAN) BPI77R. A. PenfoldDetails of various types of modem and theirapplications, plus how to interconnectcomputers, modems and the telephone system.Also networking systems and RTTY72 pages. £2.95

NEWNES AMATEUR RADIO COMPUTINGHAND BOOKJoe Pritchard G1UOWShows how radio amateurs and listeners Can'listen' to signals by reading text on acomputer screen. This book also covers theapplication of computers to radic'housekeeping such as log -keeping. OSL cards,satellite predictions and antenna design as wellas showing how to control a radio with acomputer 363 pages 0/P

PCs MADE EASY. Second EditionJames L TurleyA friendly. comprehensive memo action toevery personal computer including Macs! Thisbook is pecked with valuable tips on everyaspect of computer technology available todayand will help you to get comfortable with yourcomputer - fast. 438 pages £15.95

MORSEINTRODUCING MORSECollected Articles from PW 1382-198548pageN E1.25

SECRET OF LEARNING MORSE CODEMark FrancisUpdates for the Novice Licence. Designed tomake you proficient in Morse code in the shortestpossible time. this book points out many of thepitfalls that beset the student 84 pages £4.95

THEORYCIRCUIT SOURCE BOOK 1 BP321N.A. PenfoldWritten to help you create and experiment withyour own electronic designs by combining andusing the various standard 'building block'circuits provided. Deals with fitters. amplifiers,voltage comparators, etc182 pages £4.95

CIRCUIT SOURCE BOOK 2 - BP322R.A. PenfoldComplimentary to Circuit Source Book I. helpsyou create and expenment with your ownelectronic designs by combining and using thevarious standard 'building block' circuitsprovided. Covers signal generation, powersupplies and digital electronics, etc.214 pages £4.95

ARRL ELECTRONICS DATA BOOKDoug DeMaw W1FBBack by popular demand, completely revisedand expanded, this is a handy reference bookfor the r f designer, technician, amateur andexperimenter. Topics include components andmaterials, inductors and transformers. networks& filters, digital basics and antennas andtransmission lines 260 pages. 015

AUDIOElements of Electronics - Book 6 BPII1F. A. WilsonThis book studies sound and hearing, andexamines the operation of microphones,loudspeakers. amplifiers, oscillators, and bothdisk and magnetic recording. Intended to givethe reader a good understanding of the subjectwithout getting involved in the morecomplicated theory and mathematics.308 pages. E3.95

BEGINNERS GUIDE TO MODERN ELECTRONICCOMPONENTS BP285 R A PenfoldThis book covers a wide range of moderncomponents. The basic functions of thecomponents are described. but this is not a bookon electronic theory and does not assume thereader has an in-depth knowledge ofelectronics. It is concerned with practicalitiessuch as colour codes, deciphering codenumbers and suitability166 pages 03.95

EVERYDAY ELECTRONICS DATA BOOKMike Tooley BA. 250 pages £1.95

FILTER HANDBOOKA Practical Design GuideStefan NiewiadomskiA practical book, describing the design processas applied to filters of all types. Includespractical examples and BASIC programs. Topicsinclude passive and active filters, workedexamples of filter design, switched capacitorand switched resistor filters and includes acomprehensive catalogue of pre -calculatedtables 195 pages. 00.00

GUIDE TO CREATIVE CIRCUIT DESIGNRobert GrossblettA book that takes you through all stages ofdesign and building of (mainly) digital circuits,though many of the wimples apply to all forms ofdesign and building. One nugget from the book,'if you can't replace it don't use it'.235 pages. E17.95

FURTHER PRACTICAL ELECTRONICSCALCULATIONS & FORMULAE BP144F A Wilson. J50 firnii, f4.95

AN INTRODUCTION TO THEELECTROMAGNETIC WAVE BP315F. A WilsonThis Imtle Dock deals effectively with a difficultabstract subject - the invisible electromagneticwave. Aimed at the beginner. the book with itsbasic approach to electromagnetics, antennas,waves, propagation and constraints is a goodstarting point, complete very simple but clear

diagrams and the minimum of mathematics.122 pages £4.95

NEWNES PRACTICAL RF HANDBOOKlee HickmanThis book provides an easy -to -read introductionto modern r f circuit design. It's aimed at thoselearning to design r f circuitry and users of r 1.equipment such as signal generators andsweepers, spectrum and network analysers320 pages. E16.95

THE ARRL SPREAD SPECTRUM SOURCEBOOKMany readers thought an article about spreadspectrum communications in the April 1993 PW aspoof, but this book shows the reality of thetecnique. The ten chapters contain descriptionsof the basic theory. the designs, and thetechniques involved. and there are basictransceiver building blocks for yourexperimentation 360. pages. 0450

PRACTICAL ELECTRONICS CALCULATIONS ANDFORMULAERPM. F. A. WilsonWritten as a workshop manual for theelectronics enthusiast. there is a strongpractical bias and higher mathematics havebeen avoided where possible.249 pages 0.95

REFLECTIONSTransmission Lines & AntennasM. Walter Maxwell %WUThis will help dispel the half-truths and outrightmyths that many people believe are true abouttransmission lines, standing waves, antennamatching, reflected power arid antenna tuners.323 pages £14.50

SOLID STATE DESIGN FOR THE RADIOAMATEURLes Hayward W72018Doug DeMew W1FBBack in print by popular demand! A revised andcorrected edition of this useful reference bookcovering all aspects of solid-state design.Topics include transmitter design, poweramplifiers and matching networks, receiverdesign. test equipment and portable gear256 pages £10.95

TRANSMISSION LINE TRANSFORMERSJerry Sevick W2FMIThis is tne second edition of this book, whichcovers a most intriguing and confusing area ofthe hobby. It should enable anyone with amodicum of skill to make a balun, etc. Topicsinclude analysis. characterisation, transformerparameters, baluns, multimatch transformersand simple test equipment.270 pages £13.50

TRANSMISSION LINE

TRANSFORMERS


ANTENNAS (AERIALS)FAULTFINDING

AERIAL PROJECTS EIP105Practical designs including active, loopand ferrite antennas plus accessory units.96 pages f2.50

ALL ABOUT VERTCAL ANTENNASW. I. Orr W6SAI & S. D. Cowan W2LXCovers the theory, design and constructionoperation of vertical antennas. How to useyour tower as a vertical antenna andcompact vertical designs for restrictedlocations. All about loading coils anda.t.u.s.192 pages £7.50

ANTENNA EXPERIMENTER'S GUIDEPeter Dodd G3LDOAlthough written for radio amateurs, thisbook will be of interest to anyone whoenjoys experimenting with antennas Youonly need a very basic knowledge of radio& electronics to get the most from thisbook. Chapters include details onmeasuring resonance, impedance, fieldstrength and performance, mats andmaterials and experimental antennas.200 pages. f8.90

ANTENNA IMPEDANCEMATCHINGWilfred N. CaronProper impedance matching of an antennato a transmission line is of concern toantenna engineers and to every radioamateur. A properly matched antenna asthe termination for a line minimises feed -line losses. Power can be fed to such a linewithout the need for a matching network atthe line input. There is no mystiqueinvolved in designing even the mostcomplex multi -element networks forbroadband coverage.195 pages. f14 50

ANTENNAS FOR VHF AND UHF BP301I. 0. PooleAntennas are a very important part of anyreceiver or transmitter and in this book theauthor gives a general background toantenna operation as well as describingantennas that are suitable for vhf. andu.h.f. operation. Chapters include BasicConcepts, Feeders, The Dipole, AerialMeasurements and Practical Aspects.There is something of use for everyone withan interest in antennas in this book104 pages f4.95

ARRL ANTENNA BOOK17th EditionThis volume now in its 17th edition containsessential information regardingpropagation and constructional details ofjust about every type of antenna known toman. Included is a 3.5" diskette contain inPC programs for Yagi analysis, propagationforecasting, transmission line analysis andother. A definite must732 pages £19.95

ARRL ANTENNA COMPENDIUMVolume OneFascinating and nitherto unpublishedmaterial. Among the topics discussed arequads and loops, log periodic arrays, beamand multi -band antennas, verticals andreduced size antennas.175 pages. f9.50

ARRL ANTENNA COMPENDIUMVolume TwoBecause antennas are a topic of greatinterest among radio amateurs, ARRL HGcontinues to receive many more papers onthe subject than can possibly be publishedin OSI Those papers are collected in thisvolume. 208 pages. £9.50

ARRL ANTENNA COMPENDIUMVolume ThreeEdited by Jerry Hell K1TDAs the title suggests, this book is thethird in the continuing series on practicalantennas, theory and accessoriesproduced by the ARRL. The bookreflects the tremendous interest andactivity in antenna work, and provides afurther selection of antennas and relatedprojects you can build.236 pages. £9.50

BEAM ANTENNA HANDBOOKW. I . Orr W6SAI & S. D. Cowan W2LXDesign, construction, adjustment and

installation of h.f. beam antennas. Theinformation this book contains has beencomplied from the data obtained inexperiments conducted by the authors, andfrom information provided by scientists andengineers working on commercial andmilitary antenna ranges.268 pages. £7.50

HF ANTENNA COLLECTION IRSGBIEdited by Erwin David G4101This book contains a collection of useful,and interesting h.f. antenna articles, firstpublished in the RSGB's RadioCommunication magazine, between 1968and 1989, along with other usefulinformation on ancillary topics such asfeeders, tuners, baluns, testing andmechanics for the antenna builder233 pages 00.99

HF ANTENNAS FOR ALL LOCATIONS RSGBLes Moxon G6XN

NF ANTENNAS 1IORILLI woman

ideas 322 pages. El3 99

This bookprovides areferencesource for allh.f. antennawork, whetherit be for fixed,mobile or usingtest equipment.In effect it is amanual onantenna work,with useful tips,projects and

INTRODUCTION TO ANTENNA THEORYBP198H. C. WrightThis book deals with the basic conceptsrelevant to receiving and transmittingantennas, with emphasis on themechanics and minimal use ofmathematics. Lots of diagrams help withthe understanding of the subjects dealtwith. Chapters include information onefficiency, impedance, parasitic elementsand a variety of different antennas. 86pages f2.95

PRACTICAL ANTENNAS FOR NOVICESJohn Heys G3BDQIn this guide, written especially for newlyqualified holders of the UK novice Licence,John Heys describes in detail how to buildsimple but efficient antennas for each ofthe Novice bands up to 434MHz, as well asuseful ancillary equipment to ensure thatthey are working correctly. A completechapter is devoted to the safety andcommon-sense aspects of installing andusing a transmitting antenna.

This book will be invaluable not only toNovices, but also to any beginning amateurlooking for easy -to -build antenna systemsthat really work52 pages. £5.99

PRACTICAL ANTENNA HANDBOOK2nd EditionJoseph J. CarrAs the name suggests, this book offers apractical guide at everything to do withantennas, from h.f. to microwaves. It alsohas sections on propagation, transmissionlines, antenna fundamentals and a helpfulintroduction to radio broadcasting andcommunication. The book neatly balancesa practical approach with the minimum ofmathematics, good diagrams and a livelytext. 437 pages. £23.95

PRACTICAL WIRE ANTENNAS RSGBJohn Heys G3BDQMany radio enthusiasts have to be contentwith wire antennas. John Heys' practicalapproach to wire antennas provides plentyof ideas and projects to help get the bestout of a simple system. A helpful book, andgood reference source.100 pages. f8.50

G-ORP CLUB ANTENNA HANDBOOKCompiled and edited by P. Linsley G3PDL &T. Nicholson KA9WRI/GWOLN11.This book is a collection of antenna andrelated circuits taken from Sprat. the G-QRP Club's journal. Although most of thecircuits are aimed at the low -powerfraternity, many of the interesting projects

are also useful for general use. Notintended as a text book, but offers practicaland proven circuits. 155 pages. f5.00

RADIO AMATEUR ANTENNAHANDBOOKW. I. Orr W6SAI & S. D. Cowan W2LXYogi, Quad, Quagi and LPY beam antennasas well as vertical, horizontal and sloperantennas are covered in this useful book.How to judge the best location, DX antennaneight, ground loss and radials.188 pages f7.50

RECEIVING ANTENNA HANDBOOKJoe CarrYour receiver is only as good as yourantenna. This book is a complete guide tohigh performance receiving antennas. It isa comprehensive examination of antennasintended specifically for receivingpurposes. An essential addition to yourtechnical library, the listeners antennabible. 189 Pages f17.50

SIMPLE, LOW-COST WIRE ANTENNAS FORRADIO AMATEURSW.I.Orr W6SAI & S. D. Cowan W2LXEfficient antennas for Top Band to 2m,including 'invisible' antennas for difficultstation locations. Clear explanations ofresonance, radiation resistance,impedance, s.w.r., balanced andunbalanced antennas are also included.188 pages f7.50

W1FB'S ANTENNA NOTEBOOKDoug DeMaw W1FBThis book provides lots of designs, insimple and easy to read terms, for simplewire and tubing antennas. All drawings arelarge and clear making construction mucheasier. There is no high-level mathematicsin this book, lust simple equations onlywhen necessary to calculate the length ofan antenna element or its matchingsection. 123 pages. £6.95

YAGI ANTENNA DESIGNDr James. L Lawson W2PVThis book is a polished and expandedversion of a series of articles first publishedin Ham Radio following on from a series oflectures by the author, who was well-known as the expert on Yagi design.Chapters include simple Yagi antennas,loop antennas, effect of ground, stackingand practical antenna design.210 pages f10.95

25 SIMPLE AMATEUR BAND AERIALSBP125E. M Noll63 pages f1.95

25 SIMPLE INDOOR AND WINDOWAERIALS BP1.36EE. M. Noll50 pages. E1.75

25 SIMPLE SHORT WAVE BROADCASTBAND AERIALS BP132E. M. Noll63 pages. f1 95

25 SIMPLE TROPICAL AND MW BANDAERIALS BP145E. M. Noll54 pages £1.75

£50 PRIZE DRAW

If you are ordering a

book don't forgetyou'll be entered

into our prize draw.See the top of page

72 for full details.

GETTING THE MOST FROM YOUR MULTIMETERBP239R. A. PanfoldThis book is primarily aimed at beginners. It coversboth analogue and digital multi -meters and theirrespective limitations. All kinds of testing isexplained too. No previous knowledge is requiredor assumed.102 pages E2.95

HOW TO USE OSCILLOSCOPES 8 OTHER TESTEQUIPMENT BP267R.A. PenfoldHints and ideas on how to use the test equipmentyou have, to check out, or fault find on electroniccircuits. Many diagrams of typical waveforms andcircuits, including descriptions of what waveformto expect wrth particular fautts, or distortion inaudio amplifiers 704 pages £3.50

MORE ADVANCED TEST EQUIPMENTCONSTRUCTION BP249R.A.PenfoldA follow on from Test Equipment Construction(BP2481this book looks at digital methods ofmeasuring resistance, voltage, current,capacitance and frequency. Also covered is testingsemi -conductors, along with test gear for generalradio related topics102 pages £3.50

TROUBLESHOOTING WITH YOUR TRIGGERED -SWEEP OSCILLOSCOPERoben L GoodmanThis book steers you through the various features -old and new - tnat scope technology provides andis an invaluable guide to getting the best out of yourscope. An overview of available scopes will helpyou choose the one that best suits your needs.Areas covered include spectrum analyst, testapplications, multiple -trace displays, waveformanalysis, triggering, magnified sweep displays,analogue and digital scopes, etc 309 pages. E17.50

MORE ADVANCED USES OF THE MULTIMETER8P2 MR.A. PenfoldThis book is primarily intended as a follow-up toBP239. Getting the most from your Multi.meter. Byusing the techniques described in this book youcan test and analyse the performance of a range ofcomponents with lust a multi -meter (plus a veryfew inexpensive components in some casesl. Thesimple add-ons described extend the capabilities ofa mule -meter to make it even more useful. 96pages 02.95

OSCILLOSCOPES. HOW TO USE THEM, HOW THEYWORK 3rd EditionIan Hickman248 pages. E15.95

TELEVISIONATV COMPENDIUMMike Wending ORIONThis book is for those interested in amateurtelevision, particularly the home constructionaspect There isn't a 70cm section as the authorfelt this was covered in other books. Other fieldssuch as 3cm TV, are covered III depth A must forthe practical ATV enthusiast 104 pages E3.00

INTERFERENCEINTERFERENCE HANDBOOK IUSA)William R. Nelson WA6FQGHow to locate & cure r f i. for radio amateurs,CBers, TV & stereo owners Types ofinterference covered are spark discharge,electrostatic, power line many 'cures' aresuggested 250 pages E9.50

MAPSNORTH ATLANTIC ROUTE CHARTThis is a five -colour chart designed for the ATCin monitoring transatlantic flights. Suppliedfolded740 x 520mmE6.513

RADIO AMATEURS MAP OF THE WORLDThis a brightly coloured map clearly showingcallsign prefixes for the world and is up-to-datewith recent European boundary changes.Supplied folded in a clear plastic wallet980 x 6110nen E5 95

0TH LOCATOR MAP OF EUROPETres& OKSPZRadio Map ServiceThis comprehensive map of the Europeancallsign area has now been updated andenhanced. This well thought out, coloured mapcovers from N Africa to Iceland and fromPortugal in the west to Iran in the east. Folds tofit into the 105 x 240mm clear envelope1080 x 580mm. £5.95


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HF 300kHz-29995 MHzAll Mode Transceiver

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