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A Guide to Ts AMTOR The Trio ITU 30SP -a goo ri ommon Man WOOD & DOUGLAS THEGAMMA TWIN We are offering 2 METRE FOLDED 1/2 WAVE ANTENNA Copyright Gamma Aerial Products 1982 Q. R. K. in our new illustrated catalogue and price list. This antenna is based on theverypopular and Q. R. K? Quality Radio Kit's of course, suitable for VH F, successful"SLIMJIM" UHF, FM or Video techniques. If you can solder you design. can assemble our products. If they don't workfirst time apart from expressing surprise we will service and check your handiwork We will also let you know where you went wrong. The GAMMA TWIN has thefollowingunique INTERESTED? Then send an A5 stamped addressed features: envelope for your copy of this new product handbook Our extensive range is held as stock whenever poss- ible for immediate dispatch against you written or credit card order. * VERY LOW ANGLE OF RADIATION. REMEMBER that apart from offering Q. R. K's we also service, back-up and believe in our products. TRY ONE * ADJUSTABLE RADIATOR. Unit 13 (140-150 MHZ) Youngs Industrial Estate BARCLAYCARD Aldermaston Access VISA Reading RG7 4PG Tel: 07356 5324Tx: 848 702Aft * COMPLETELY WEATHERPROOF CONNECTING BOX

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. nave not yet heard an FT -101 sound any better than when used with The hey

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audio equalizer Is Believing . . and 115.5 WEST MIDLANDS LYE 891132/891474 microphone TRADE ENQUIRIES WELCOME I Acting Editor VOLUME TWO NO.7 JULY '84 Steve Ireland, G3ZZD Consultant Editor Dave Bradshaw Advertisment Manager REGU AR LUMNS David Gadsden, G4NXV Classified Sales Executive LETTERS 4 Debbie Miller RADIO TODAY 6 Managing Editor Ron Harris RADIO TOMORROW 10 Chief Executive T. J. Connell RADIO YESTERDAY 32 PRACTICALITIES 58 Published by: Argus Specialist Publications Ltd., 1,Golden Square, London WI R 3AB. Telephone: 01-437 0626 A SINGLE -CHANNEL TRANSVERTER FOR 70cm 21 Distributed by: Hugh Allison, G3XSE, describes a cheap and crafty way of gettingon the band SM Distribution Ltd. PLAIN MAN'S GUIDE TO 6m RECEPTION 47 Printed by. Step-by-step construction of a 6m converter with Jack Hum, G5UM The Garden City Press Ltd. Subscription Rate: UK £14.00 0/Seas Sur: £14.45 0/Seas Air: £27.00 ANTENNA PLANNING 13 Ham Radio Today, Worried about the legalities? Steve Voy tells all Subscriptions Dept, Infonet Ltd, A GUIDE TO AMTOR 23 Times House, Resident keyboard man, Ken Michaelson, G3RDG, tellshow to do it 179 The Marlowes, Hemel Hempstead, EARTH -MOON -EARTH WORKING- SIMPLY 27 Herts HP1 1BB ABC In part III, Charles Suckling, G3WDG, describes EMEoperating procedures Tel: (0442) 48432 THIS IS PY1ZFX MOBILE Ham Radio Today is normally published on 43 thefirst Friday inthe month preceding Travel across South America with Roger Crofts,G3UPK, and Mary Carpenter cover date. The contents of this publication including all articles, designs, plans, draw- RADIO BUILDING BLOCKS 55 ings and programs and all copyright and Frank Ogden, G4JST, gets stuck into FM, in particular IFstrips other intellectual property rights therein belongtoArgus Specialist Publications Limited. All rights conferred by the Law of Copyright and other intellectual property rightsandbyvirtueof international copyrightconventionsarespecifically YAESU FT203R 2m HANDHELD TRANSCEIVER 18 reserved to Argus Specialist Publications Steve Ireland, G3ZZD, investigates the latest fist -full of 2m Limited and any reproduction requires the prior written consent of the Company. © TRIO TS530SP HF TRANSCEIVER 36 1983 Argus Specialist Publications Ltd. All Eminently practical thought Angus McKenzie, G3OSS, and HRT reasonable care is taken in the preparation of the magazine contents, but the publishers ADDENDUM cannot be held legally responsible for er- 42 rors. Where mistakes do occur, a correction will normally be published as soon as possi- NEXT MONTH IN HRT 42 ble afterwards. All prices and data contain- ed in advertisements are accepted by us in AD INDEX 59 good faith as correct at time of going to press.Neithertheadvertisersnotthe Free Readers' Ads 60 publisherscanbeheldresponsible, however, for any variation affecting price or Emporium 63 availability which may occurafterthe publication has closed for press. Classified 65

HAM RADIO TODAY JULY 1984 3 the fault myself and wish others to band generally they can contact me at COMPONENT SHORTAGES benefit from my experience. The 934 MHz Club UK, PO Box 424, If you are having the above Chelmsford, Essex CM6 3UR. Sir,I am an avid homebrewer and take symptoms, take a look at the IF PCB We have received an excellent your magazine in part for the excellent and alongside Test Point 10 which is response from the initial mailing and new construction articles. There is a on the output from T09 and feeds into applications for memberships arrive every positive approach in your magazine to the Gate of Q2010. Check if R84, a day. The Club now has a membership of encourage homebrewers. However, it 100K resistor has been installed. R84 over one hundred. should be brought to the notice of will be written on the topside of the The QSL Bureau referred to in the prospective builders of the availability board. R84 had been left out in my initial letter is now operating suc- of the parts required. My recent receiver; installation (of this) will cure cessfully. We have a reliable QSL experiences certainly damp the the overloading, improve selectivity Manager who will ensure that QSL's enthusiasm to build. The latest project and signal-to-noise ratio. received are forwarded to the had a "out of stock" label to over half The above is not an isolated members. the parts required. The previous instance as this seems to be common Lastly may I thank you in advance project held for six weeks pending in the batch of transceivers between for any support that your Magazine will supply of parts. 2M071000 and 2M071 100. give to the Club. To the already high price of Mrs Glenys Anthony, Secretary components is added not one lot of C.H. Castle, VK5KL postal charges but possible two or three. To the suppliers who can boast NOT STAND-OFFISH adequate stocks and quick Sir, As a fairly new licencee may I make a replenishment will go success and the 934 MHz CB few comments about Tom Wylies' others will drop out eventually. (GM4FDM) letter in May HRT ("Where My latest order has been sent Sir,I am pleased to inform you that The have all the Class B Licences gone"?) labelled "All parts are required. If only 934 MHz Club UK has now been First of all, up until Ilet my licence PART available, CANCEL (this order). formed. We have a strong steering run out, I was quite happy to talk to committee who have already met several anyone who happened to give out a George Clarkson, G3RHM times. general CQ call. We are, of course, aware that it is When I first appeared I was given Obtaining components for radio virtually impossible for us to contact every help and assistance and have made projects has never been easy and has everyone using the band without the many new friends. Hopefully I will be certainly got progressively more assistance of publications such as able to make some more among the G1 s difficult in recent years. In general, yourselves. I would therefore be grateful who are appearing. components for projects in HRT can if you would publish details of the Club in My temporary absence from the be obtained from Maplin, Ambit and your Magazine. Should any of your bands is due to my attempt at the morse Bi-pak - large suppliers with a readers be interested in the Club or the test and the fact that I didn't want to pay substantial turnover - without too much difficulty. However the component business is not the most profitable of businesses and as you are probably aware, profitably is all in the present economic/political climate.. . In order to circumvent this problem HRT tries to publish designs for which a kit of parts is available. When you count up the aggro, accumulated postal charges etc, the mark up on kits seems pretty reasonable - especially when the kit supplier has to cope with this aggro too!

FT102 PROBLEMS? Sir, The reason for this letter is so that perhaps somewhere in your publication you could advise owners of FT102 Transceivers who may be experiencing the same as with my new purchase, namely poor selectivity, overloading and poor signal-to-noise level on all bands. Returning the equipment to the import agent has not been successful in clearing the fault.I have finally found

4 HAM RADIO TODAY JULY 1984 £12 twice (once to renew the VHF licence and another £12 for the HF when I finally pass the morse). In doing the morse I do not want to 'escape' two metres nor do I want to attain the 'real standard', but at least when I have the HF licence I can use any mode on any band. I shall have to go back to 2m/70cm as that is allI have at the moment (I have an FT290 R and a Pye Westminster). As regards repeaters, there are several very good ones in my area and as I also do a lot of driving I tend to listen to one of them for ease of operating. This has meant that a) people know how to get hold of me, and b) there is someone to talk to the new G1 s when no one else is around. D. J.. Ackrill, ex-G6VMQ PS I am looking forward to getting back on the bands with a new callsign.

Glad to hear that you will soon be back on 2m/70cm. Recently I had contact with a new G1 on 2m SSB who complained of an absence of replies to his CQ calls despite a fairly active band. He had a good signal with me despite his relative distance. Let me re -iterate Tom Wylie's plea: c'mon lads and lasses, when you hear a new callsign give then a call. Make friends, don't just monitor.

NOVICE LICENCE

Sir,I should be grateful if you would publish this letter.I realise that you will be innundated by replies but I believe that people like Mr Compton should be put right for once and all. In reference to Mr Compton's letter, ie published in HRT May issue: obviously FOR R046.PiC)/ OB6e -7" Mr Compton is sorely deluded if he thinks qe) _ R that the amateur radio fraternity needs a Ros/27-, "O' novice licence. Our hobby has prospered kicy.1-67 F6,1 for years without a novice licence and it will continue to do so, provided people like Mr Compton are not let loose on our George Metcalfe, G6VS (Letters, April copy of relevant sections of the Signal bands. '84 HRT). Training (All Arms) 1928 manual. Mr Compton's idea does not stretch He states it was not until 1938 that a full Referring to paragraph 6 ("To obtain beyond that of a typical "CB-er". The phonetic alphabet was introduced for uniformity by users of military telephones novice licence suggested is just an Service Use. This is incorrect. a card is affixed to every field telephone excuse to legalise pirate SSB. The I am ex -army AIS County Regiment with the complete phonetic alphabet on recomendations are pathetic. 250 watts (Royal Signals trained). We were it."), the card had, some time before max at night is very ORO, considering teaching full alphabet phonetics in 1938, been replaced with a black metal QSOs are quite possible world-wide 1929/30/31 etc. plate with the full phonetics embossed using 5 or 10 watts. Besides, how many on it. people will operate after 1 am - is Mr These were: One explanation is that there may Compton nocturnal? Ack Nuts have been two training manuals, one, as If Mr Compton does not like 27 MHz CB, Beer Orange quoted by the Curator of the R. Signals we suggest he uses 934MHz and leaves Charlie Pip Museum, in G6VS's letter, and the other amateur radio alone because he is not Don Queen as mentioned above, as issued to the going to get a CB paradise through our Edward Robert Field units of the rest of the British Army. hobby. Freddie Sugar The Royal Corps of Signals were P. Juden, G6 ZBN George Toc rather more specialized than the rest and P. Williamson G4 WUU Harry Uncle did not introduce the full phonetics until Ink Victor 1938 by which time it's usefulness had I have very little to add to my remarks Johnny Willie been assessed by Regimental Signallers. after Mr Compton's letter in May HRT King X-ray M. Hughes, GW3VFZ except that I think he is being hopeful London Yorker rather than cynical. I would also like to Monkey Zebra The phonetic alphabet in the manual repeat my assertion that the RAE tests quoted is the same as the alphabet the candidates application to radio rather These come much easier to the mind above. than his or her intelligence and may be than the present day ones. passed by almost any candidate with plenty of the former. Retired these days, but still playing with Please address correspondence to: CB Ham Radio Today, PHONETIC REVELATIONS 1, Golden Square, Sir, With reference to previous LONDON W1R 3AB. Sir, reference the item on Phonetics by correspondence on Phonetics I enclose a

HAM RADIO TODAY JULY 1984 5 have recently moved from their old premises in Brentwood to a rather nice showroom in5 The Street,Hatfield Peverel, near Chelmsford. A crowd of around 50 enthusiastic amateurs, in- cluding HRT's Dave Gadsden, G4 NXV, attended the Trade/Press Party on 30th March. The Editor was unable to attend owing to an importune attack of influen- za, missing quite a good shindig... Dave was so enthusiastic that he actually made the first purchase, a 5 /8 whip... Arrow received flowers, homemade cakes and wine and many good wishes from their regulars and would like to extend a very big thank you fortheir support.Peter Clarke, Stop Press! with the UK increase of 20%.Although G3 LST, of Arrow reports over 500 the US have no equivalent to our Class customers on the first day at Hatfield B licence, they do have a novice licence Peverel! The winner of the Draw for all those (CW only), for which the annual growth who wisely bought subscriptionsto was 9 4%, and their General class, HRT from our stand atthe RSGB very similar to our Class A in terms of BARTG Go Amateur Radio Convention was Mr BL structure, was down by 0 7%, accord- Chesworth of Wrexham, Clwyd. Mr ing to Wayne. The crossover from CB to DATACOM Chesworth wins a 7 element 2m yagi Amateur Radio is undoubtedly responsi- kindly donated by MET antennas and ble for the large percentage increase in The British Amateur Radio Teleprinter Group (BARTG) recently launched their the CQ Centre. thiscountry.Some RAEInstructor friendsof theEditor report asmall newquarterlymagazinecalled percentage decrease in the popularity of DATACOM. This replaces the BARTG Examination classes for the first time in Newsletter, and is sent free of charge to Interested in the last few years. Could the boom all members of the Group. Microwaves?... perhaps have reached it's peak... DATACOM isdedicatedtoall Wayne has also recently proposed forms of data communication by con- The MICROWAVE SOCIETY looks after to the FCC, American equivalent of the ventional teleprinter and by computer, the interests of all those operating on, DTI, a change to the licence conditions including RTTY, AMTOR, Packet Radio, orinterestedin,frequencies above whereby biennial re -testing of the radio FAX and so on. The firstissue of 10 GHz. amateurs'proficiency inMorse DATACOM, dated Spring 1984, is 116 Theirwellknown DATAPACK becomes mandatory. He has also pro- pageslong,and isapparentlythe (which includes all you need to know to posed that amateurs be required to largest publication ever produced by build a complete system for under40) demonstrate a 5wpm increase in their BARTG. It contains a large number of has now been completely revised and is morse ability to an ultimate figure of technicalarticlesofinterestto now in its 5th edition. 35wpm at the end of each two year teleprinter and computer enthusiasts, The societies newsletter period. Amateurs failing the test would plus a number of special interest col- "WAVEGUIDE" keeps member up to begiven a periodof 60 days to umns on emergency communication, date with society affairs and also in- demonstrate the required rate or lose FAX, clubs, etc. cludes updates for the DATAPACK. their licence! There is a special feature on Packet This year sees the start of the societies Radio, with a tutorial article on the prin- awards and certificates scheme for ciples of Packet Radio for beginners, achievements on the frequencies above Arrow Hit The plus full details of a Packet Radio experi- 10 GHz. Some indication of the growth ment being carried out in Cambridge, of interest in microwaves is the fact Target! using BBC microcomputers. There is that nearly 200 new members joined also a full-lengtharticledescribing It has probably not escaped the notice GB3PT, the RTTY repeater at Cam- the society during 1983. of HRT readers that Arrow Electronics Thesocietylooksforwardto bridge, with information on how to use meeting as many microwaveen- Dave Gadsden,G4NXV, at Arrow it and details of plans for upgrading it to thusiasts as possible on its stand at the ASCII operation. NEC rally and at the large number of For full membership details, please club talks undertaken in the course of contact Mr. John Beedie, G6 MOK, 161 theyear.FulldetailsfromThe Tudor Road, Hayes, Middlesex UB3 MicrowaveSociety,81 Ringwood 2QG. (01-561 0010). Highway, COVENTRY CV2 2 GT. Amateur Radio Letter From And CB In America Harmony

In arecenteditorial, Wayne Green, A group of radio amateurs and keen CB publisher of 73 magazine, claimed that operatorswill be takingtothe the increase in American amateur radio Sutherland Hills on the 2nd and 3rd of licences over 1983 was 2 6% - June 1984 in aid of the Highland Scan- which contrasts somewhat markedly ner Appeal. The amateur radio group

6 HAM RADIO TODAY JULY 1984 will be operating on the 20, 40, and 80 cepted by the keeper, Bill Tuck G8 KZP, and alignment of 3 cms equipment. The metre bands SSB/CW and also on "Whalebone Cottage", Wells Next The station operates on 10 368 GHz with 144.550MHz SSB. The CB STATION Sea,Norfolk,NR12 1 EN, orthe facilities for both wide and narrow band will be using 4 watts FM and hoping to treasure Malcolm E. Amis G4VDC, "Ar- users, and is regularly heard in Suffolk work many CB enthusiastsfar and cantell", 5, Waveney Close, Wells Next and Hampshire. GB3 BH is the proposed wide. The Amateur Radio call sign will The Sea, Norfolk, NR12 1 HU. 1 3 GHz (23cms) FM Beacon/Repeat- hopefully be GB2 DOS (which stands for Therepeatersupport groupof er station, presently being constructed DUKE OF SUTHERLAND) and the loca- GB3 BP haveaskedpermissionto by members, to be located at Bushey tion will be on the summit of Beinn change the callsign to GB3 WS (West Heath. This station is unusual as it will A'Bhragaidh (XR10B) 1293 feet ASL Sussex?) and this has apparently been act both as a Beacon, and as a Repeater and 1 1/2 miles North West of Golspie. approved. Some difficulties with the re- Station. Frequencies will be 1297 0 "CB YL'S and XYL'S will be providing location of the long licensed GB3 AE MHz TX and1291 0 MHzRX. the Scottish Fare to keep 'the spirits (Skipton, Yorks R5) has meant that it Horizontal polarisation will be used. high' during the two day event, as the has not been operational. Contributions are always welcom- 'Mountain Haggis' is out of season at The South West Hertfordshire UHF ed by the Group to pay for site rental this time of year(!)" says the press Group are responsible for providing and and electricity charges and should be release. Special QSL cards will be sent maintaining three UHF/SHF stations in sent to Mr. Brian Greenaway G3THQ at fromboth CB and Amateur Radio this area. GB3HR is their 70cms FM 5 Lansdowne Grove, London NW10 Stations. Repeater Station located at Stanmore. 1 PL. Reception reports are also very Thisstation was originallysitedat welcome and should be sent to the Bushey Heath, however, due to finan- Secretary, Mr. Trevor Groves G4 KUJ, New UHF GaAs cial and coverage problems, the new 62 The Crescent, Abbots Langley, Wat- site at Stanmore was selected which ford, WD5 ODS. FET gives a worthwhile advantage on both Members of the Group are available accounts. Regrettably they have found to Clubs for talks and demonstrations, The new Mitsubishi low noise GaAs a couple of gremlins at the new site, for further information please contact FET type MGF 1404 is now available which, up untilrecently, has meant the Secretry as above. from Aspen Electronics. This is a super reduced transmitter output power and low noise GaAs FET with a N -channel reducedreceiverperformance.The schottky gate which is designed for use transmitting aerial fault has now been in S toKu bandamplifiers.The rectifiedandusersreportgood Radio Japan hermeticallysealedmetalceramic coverage to mobiles over the areas of package "assures minimum parasitic St. Albans, Edgware, Harrow and Wat- Expands Service losses and has a configuration suitable ford. They hope to have the receiver To Europe for microstrip circuits."Featuresin- problem cured within the next month. clude typical high maximum frequency GB3HR can be found on 70cms FM HRT's broadcast enthusiasts may be in- of oscillation of 90 GHz; noise figure of channel RB14 (433 350 MHz TX, terested to hear that Radio Japan has 1 6 dB at12 GHz; and againof 434 950 MHzRX). GB3SWHis expanded its overseas service to Europe 10 5 dB at 12 GHz. SWH's 10 GHz (3cms) Beacon Station and the Middle East by starting relay located at Bushey Heath. The device is broadcasts on the 2nd April, from a horizontally polarised and provides a high-powered transmittingstationin Repeater Update good source for checking propagation Africa. The new relay broadcast will -29 MHz Miss Yuka Nukina and Mr Hiroshi Shioguchi of Radio Japan, Repeaters? announcers of the 'DX Corner' programme

There seems to be a growing interest in the possibility of 29MHz FM repeaters. There are presently six proposals with the Repeater Management Group; for Leicester, Daventry, London, Barnsley, Cornwall and Blackburn. The Leicester Group have recently drafted a complete technical specification for arepeater which is awaiting agreement from the HF committee. A recent meeting was held to form a new repeater group for GB3 NN (RB2), located 3 Km south of Wells Next The Sea in Norfolk (AM095F). Site approval and a franchise has been received, also licencing procedures areinprogress within the DTI, and it is hoped to have the repeater operational at its new site by June/July 84. The repeater is a Pye 460 UHF unitconvertedto 70cm repeater use, the aerials are 4 stacked J poles for Rx and 4 stacked dipoles for Tx, the site is 77 Mts ASL, with aerials at 25m high and an ERP of 12 watts. Donations from any prospective users of GB3 NN would be gratefully ac-

HAM RADIO TODAY JULY 1984 7 provide listeners with greatly improved clarity of reception. Listeners in these areas have so far found it difficult to receive clear broad- casts direct from Japan. Since October 1979, Radio Japan has been relaying broadcasts to Europe and the Middle East for one hour daily from Radio Trans -Europe in Sines, Portugal. Now from the Moyabi station in Gabon, West Africa, Radio Japan is offering relayed broadcasts on a 500 kw transmitter for six hours a day in English, Japanese, German, French, Italian, Swedish and Russian. The programmes are being sent from Tokyo via the Intelsat com- munication satellites over the Indian and the Atlantic Ocean. The time schedule and frequencies ofrelaybroadcast from Moyabiin English are as follows: General Service 0 7 0 0 -1 800 GMT (English) 21 575 MHz,1500-1600 GMT (English) 21 550 kHz. New regular featuresinclude:ScienceToday; reports on progress in science, medicine and high technology in Japan; and DX Corner; facts and news for short wave Reg, G6XO, with the winning entry of the Chesham DARS buffs on DX broadcasts around the Construction Contest, .a 20/80m Trx by G4IWS world. The first meeting and election of committee was held on March 20th, by Walters and Stanton, Adonis, have 1984 and was well supported. just announced their accessory AP -1 to QTI Talking Meetings are to be held at The overcome this problem. This is an 8 pin Newspaper DesignBlock,EastleaSchool,Hilda microphone plug fitted with an amplifier Road, Canning Town, London E16 and and drawing power from the existing QTI Talking Newspaper for blind and will commence at 1930 hours until sighted radio amateurs has DC point on the Icom 8 pin microphone partially 2130hours.The datesforfuture transceiver socket. All that been granted full charity status by the meetings in 1984 are: Tuesday, 8th is to wire this plug onto any current Charity Commission, (No. 326454). May; Tuesday, 10th July; Tuesday, Donations and offers of financial sup- microphone, thus enabling it to be used 11th September and Tuesday, 6th with all modern Icom transceivers. The port may be directed to: Mr. J. Feeley November. price of this unit is £ 1 0.95 and they (G4 MRB), Chairman QTITNA, 79 Nar- On May 8th RAMUG will have a may be ordered direct from Waters and row Lane, North Anston, Sheffield S31 demonstrationof'Radio Contact Dawn Tel:0909 talkand Stanton at 18 /20 Main Road, Hockley, 7 BJ.or Teletype(RTTYI'byChrisFogarty Essex SS5 4QS. 566301 between 10.00 am to 4.00 (G4 KBL) and on July 10th a demonstra- pm. Monday to Thursday. tion and chat about 'Database and Log. Keeping in Amateur Radio' by John Hopkins(G60 VL)and Rob Webb Radio Amateur (G4 KCS). The cost of membership of the Micro User Group group will be £2.00 per annum and all enquiries should be sent, enclosing a (RAMUG) stamped, addressed envelope to: The Secretary, RAMUG, c/o R.A. Webb, A new group haS recently been formed 39, Aldworth Road, Stratford, London El 5 4 DN. for, astheheadingshows,radio amateurs who usetheir microcom- puters within the hobby. Itis primarily Icom Microphone for owners of the BBC MICRO, although other types of computer may be sup- Matching ported if demand is apparent. They intend to hold meetings on a One of the problems radio amateurs bi-monthly basis in East London but will have experienced with the latest Icom unfortunately Not be running a 'Postal series of transceivers is the difficulty of Club' as RAMUG feel that more can be using microphones. other than those achievedbypractical useand supplied by Icom. The reason for this is demonstrations of various peripherals, that all Icom microphones have small hardware, software and also discus- amplifiersbuiltintothe microphone sions 'on the air'. RAMUG propose to housing and thus the input sensitivity of Match your have a 'net' on 145 200 MHz (S8) on the transceiver is too low for normal mike to your Friday evenings at 1930 hours local microphone outputs. Icom! time. A company represented in the UK

8 HAM RADIO TODAY JULY 1984 81-PAK BARGAINS MINIATURE TOOLS FOR HOBBYISTS SIGNAL INJECTOR 11,1 PIEZO ®Miniature round nose side cutters insula- MiniatureroundI.e.-electronic ted handles 44inch length. Order No: Y043 buzzer. White Plastic Low consumption FLEXEY DRIVER Frequency. 4kHzapprox. CS)Miniature long nose pliers - insulated Output 70d6 IA1 @ 1, typ handles 54inch length. Order No: Y044. A flexible shaft screwdriver for those awkward Simple push button operation. Oscillates at 700 to get at screws. Overall length 8 finch. Order - 1k Hz with harmonics to 30MHz. 1.4V p/p Power 12VOL 4mA No: FS -1 Rat blade 4mm FS -2 Cross point no. 1 output. Impedance 10k11 Ideal for trouble Dims 22 Idia I 11 5mm Miniature bend nose pliers f1.75 each. shooting with audio equipment. One "AA" Fixing Centres 26 5mm insulated handles 54inch penlight battery supplied. 0/No VP96 £2.50 0/No VP 107 length. Order No: Y045. PIEZO Miniature end nippers - LOGIC PROBE Piezo buzzerWhite plastic 90mm insulated leads For use on a c mains handles 44inch length. GRIP -DRIVER Frequency 3 5kHz approx Order No: Y046. 8inch long screwdriver with spring loaded Output 85dB 141 @ lm typ Automatic levelling. White LED indication. Power 2409a c 5mA Miniature snipe nose pliers with side grip on end to hold screws in position Minimum width of measuring pulse 30 cutter and serrated jaws - insulated while reaching into those difficult places. 0/No VP 108 Dims 32 Idia It. 14mm millisecs.Maximum input frequency 10M Hz. Fixing centres 38mm handles 5inch length. Order No: Order No, SD -1Flat blade 4mm SD -2 Input impedance: 10042 Y042. ALL AT £1.25 each Cross point no.O. £95p each. Power consumption: 40mA maximum Power supply. 4.5 - 18 V d.c. ELECTRONIC 13 PIECE TOOL KIT AND CASE ORDER No VP97 £10.51 Miniature electronic buzzers Solid stateIvory plastic 150 13 -piece tool set housed in CURRENT/ C ECKER leads Frequency 500 Hz 'attractivemouldedplastic approx ,case with clear sliding cover D ms 22 16x 15mm , 1off 5" snipe nose "radio" Output 82dB 141 @ m typ pliers with side cutters 1 Fixing centres 26mm Heavy duty test prods with built-in indicators 3V 25mA 0/No VP 82 6V 25mA VP 83 off 44" side cutters 1off for testing polarity: indicates whether a.c. or 44" end cutters 2 off hex. 9V 25mA. 0/No VP 84 12V 25mA VP 86 d.c. 3.5V to 400V. 80p each "Allen" key drivers 2mm and 0/No. VP98 £2.50 2.5mm;2 offcross -point SUB -BOX 'Phillips" drivers No. 0 and TESTER "-cr--- A neat swivelling disc provides t close tolerance substitution re- No. 1 (with tommy bar) 6 offprecisionscrewdrivers. sistors of 36 preferred values J. ra I , from 5ohms to 1Kohm. Simply _ _ . Sizes from lmm to 3.5mm Universal tester with ceramic buzzer. Tests fix clips into circuit and swivel diodes, transistors, resistors, capacitors and ONLY £7.50 ORDER No. VP102 until optimum result is continuity. One "M" penlight battery included. achieved. Test current: Max 20 0/No. VP 112 f4.75 PRECISION BRAND NEW LCD Test voltage: 12V Response range: 100M11 MINIATURE VICE JEWELLERS' TOOLS DISPLAY MULTITESTER Max voltage: 500V Miniatureplasticand metal Rustproof,TemperedHandlesand Blades. RE 188m Internal resistance: 39041 vice with strong suction base Chrome Plated Handles. Swivel Heads for use LCD 10 MEGOHM INPUT IMPEDANCE Len th: 135mm 0/No VP99 for portability. Single action to secureorreleasesuction. on Precision Work. '34 digit '16 ranges plus hFE test facility for _ CIRCUIT Plastic jaws with rubber pads 5721 SCREWDRIVER SET PNP and NPN transistors 'Auto zero, auto 20mm wide,open outto polarity 'Single-handed, pushbutton operation 40mm. Dims: 85'65 x 6 precisionscrewdriversin hingedplastic 60mmapprox. case. Sizes - 0.8. 1.4, 2. 2.4, 2.9 and 3.8mm £1.75 'Over range indication '12.5mm (4 -inch) large FANTASTIC VALUE LCD readout 'Diode check 'Fast circuit D.C. contnuity tester for circuit checking on all low voltage equipment and components. Diode 0/No VP 95 ONLY f1.60 5731 NUT DRIVER SET protection 'Test leads, battery and instructions 5 precision nut drivers in hinged plastic case. checking also possible. Takes two M batteries. included. 90cm lead has crocodile clip. Body length LEARN A UNGO! With turningrod.Sizes - 3,3.5.4,4.5 and 5mm f1.75 Max indication 1999 or -1999 145mm 0/No. VP100 75. PILLOW SPEAKER Polarity indicationNegative only Slim under pillow unit. 8ohms 2"speaker.1.5mleadwith 5741 TOOL SET Positive readings appear 1 Red plastic case with adjustable fixing 3.5mm mono jack plug. Black. 5 precision instruments in hinged plastic case. without4- sign Dims: 65 (dia.) x 17mm. Crosspoint (Philips) screwdrivers - HO and HI bracket. Emits high-pitched wailing note of Input Impedance 10 Megohms O'No VP 88 E1.25 Hexkeywrenches. Sizes - 1.5. 2 and varying pitch - 100 cycles per minute. Dims - Zero adjust 2.5mm f1.75 Automatic 90mm (dia.) 60mm (depth). Power - 12v DC. METRIC & Sampling time 250 milliseconds 0/P 90dBA 1m type. BRITISH 5751 WRENCH SET Temperature range -5°C to 50°C 5 precision wrenches in hinged plastic case. Our Price: £5.50 0/No. VP79 MEASURES Power Supply 1 x PP3 or equivalent 9V Sizes - 4. 4.5.5, 5.5 and 6mm f1.75 battery TAPE RECORDER SWITCH Steel tapes in sturdy ABs Consumption 20mW Unit to control motor of tape recorder. Plastic case Silk wrist strap These Size 155x x31mm 1.8m cord and 2.5mm plug attached. yellow coated convex tapes have inch L77 On/Off switch. Dims: 55 x 20 x 20mm. MULTITESTER RANGES and metric graduations Automatic push-button return. DC Voltage 0-200mV 0/No. VP 127 £1.00 2m long x 13mm wide 0/No VP 89 £1.00 1,000 opv including test leads & rai 3m long 13mm wide 0/No VP 90 £1.50 0-2-20-200-1000V. Acc. 0.8% POWER SUPPLY OUR PRICE £4.25 5m long-16mm wide 0/No VP 91 £2.00 Battery AC Voltage 0-200-1000V Power supply fits directly into 13 amp socket AC volts - 0-15-150-500-1,000 Acc. 1.2% DC Current 0-200uA Fused for safety. Polarity reversing socket. BATTERY TESTER Testsalltypes of battery including DC volts - 0-15-150-500-1.000 0-2-20-200mA, 0-10A. Acc. 12% a Voltage switch. Lead with multi plug standard. NICAD. Alkaline etc Takes Input - 240V AC 50HZ. Output - 3. 4.5. 6, Resistance 0-2-20-200K ohms ti all standard sizes including 6V lan- DC currents - 0 1ma-150ma 7 5. 9 & 12V DC Rating - 300 ma VP109. tern batteries and watch/heanng Resistance - 0 25 K ohms 100 K 0-2 Megohms. Acc. 1% BI-PAK VERY LOWEST PRICE aidcells Alsotestsfuses and ohms RATCHET SC' EWDRIVER KIT lamps by means of internal 9V Comprises 2 standard screwdriver blades 5 & Dims - so x 61 x 30mm. £45.00 each IPP3I battery Can also be used 7mm size. 2 cross point size 4 & 6. 1 Ratchet torecharge NICAD battenes 0/No. 1322 OUR PRICE £6.50 ONLY Leather Case for 188m £2.50 EACH handle. 5 -in -1Kit. f1.45 each. 0/No 329E3 by means of external 312Vd c Power .40y trot ,ncluded1 HIGH PASS FILTER/SUPRESSOR Fullinstructionsprovided Dims 185 103 30mm SPEAKER PROTECTOR ANTENNA COUPLER 0/No VP 101 £7.00 lapprox 1. Limits voltage to speaker or CB/TV. High pass filter. Reduces Transceiver/car radio to the permissible max., by unwanted signals picked up by antenna coupler. With co -axial FM MONITOR automatically introducing a antenna. Dims: 45 x 25 x 17mm cables. One co -axial FM monitor for 2 metre band All resistor inseries with speak- 0/No. VP 115 45p terminates in antenna plug metal Attached earphone P1259/ ers. When excessive voltage is re- and the other in P1259 S0239 connectors144MHz lOW duced the unit resets itself. Electronic plug. Dims: 67 x 46 x 30mm. maximum Dims1Bodyi 55 30 23mm voltage -sensing relay circuit. Spring terminals. Cut-off 0/No. VP 117 LOW PASS FILTER £2.00 0/No VP 120 f4.20 level adjustable from 10W -120W. Full instructions includ- Designed to reduce harmonics on ed. Dims: 85 x 74 x 25mm. the VHS and N band. Cut-off DUMMY LOAD 0/No. VP 118 £9.95 frequency: 33MHz. V.S.W.R.: Less LOW-PASS FILTER 50 ohms 30W than 1.2 to 1. Insertion loss: LP -30 UHF coaxial plug ANTENNA SWITCH 2 and 3 WAY -02dB @ 27MHz. Impedance: fitting IP12591 Co -axial switch for one transceiver 50 ohms. Dims: 80 x 55 x 40mm. 0/Ne VP 121 £5 20 AEC ar to two antennae or one antenna to 0/No. VP116 £2.75 PICK-UP COIL two transceivers. Dims: 86 x 55 x Large telephone pick-up coil for high okd 32mm (Bo).dy3 DC -DC POWER SUPPLY sensitivitySuction pad tostickto 0/No. VP 1 1 £4.50 DC to DC adaptor. Plugs into car cigar lighter aperture. telephone 90cm lead to 35 lack plug As above but 3 -way. Output 3, 4.5, 6, 7.5, 9, 12V @ 800mA. Has universal output Connects direct to cassette recorder Dims 32 Idia I 17mm Ibodyl 36mm 0.No. VP 1 14 £4.75 spider plug, also 9V battery snap and polarity reversing ,dia I sucker £1.00 facility. 0/No VP 119£2.45 0/No VP 87

Use your credit card Ring us on Ware 3182 Send your orders to Dept HRT 7 BI-PAK PO BOX 6 WARE, HERTS NOW and get your order even faster Goods SHOP AT 3 BALDOCK ST. WARE, HERTS normally sent 2nd Class Mail TERMS CASH WITH ORDER, SAME DAY DESPATCH, ACCESS, Remember you must add VAT at 15% to your BARCLAYCARD ALSO ACCEPTED. TEL. 109201 3182, GIRO 388 7006 Total order ADD 15% VAT AND 75p PER ORDER POSTAGE AND PACKING BI-PAK Postage add 75p per Total order

HAM RADIO TODAY JULY 1984 9 Your at -a -glance to what's happening around the clubs, on -the -air and in general radio- wise.

West Kent ARS: Junk Sale 12 Jun Mid -Warwickshire ARS: Fox Hunt and Barbe- Axe Vale ARC: The Entertaining Electron que S. Manchester RC: Modifications to the Wakefield DRC now meet at Ossett Communi- FT221R by G4MYB ty Centre, Prospect Road. Tonight is an 'infor- Cambridge DARC: Junk Sale at Comberton mal'. Village Hall 13 Jun S. Bristol ARC: Preparations for Longleat Rally Sutton and Cheam DRS: Receiver Fareham DARC: On-air/natter night Measurements (t.b.c.) Farnborough (Hants) DRS: Racal Equipment by 2-3 Jun HF NATIONAL FIELD DAY G3 VC X Welsh Amateur Radio Rally at Barry Leisure Nene Valley RC: RTTY and AMTOR by G3NRW Centre, Greenwood Street, Barry, South 14 Jun Colchester RA: How Banks Communicate(?!) Glamorgan. Trade stands, Bring and Buy, Edgeware DARS: Electronic Music by G4BZY refreshments, bar and a swimming pool! Close Conwy Valley ARC: AGM at Green Lawns to Barry Island Pleasure Park. Free Parking. Hotel Talk -in S22. Open 11-5 pm. Info Reg Rowles 15 Jun S. Manchester RC: 160m DFing Today by 0222 565656 G3WFT RSGB 70 MHz Contest and SWL Cambridge DARC: ring PRO for details Horndean DRC: Matching Units by G3GVC Sutton and Cheam RS: Maritime Radio (t.b.c.) Leighton Linsdale RC: Quiz with Aylesbury Harrow RS: Informal Vale and Milton Keynes DRS 17 Jun RNARS Mobile Rally at HMS Mercury, near Stourbridge ARS: ring PRO for details Petersfield, Hants. Events for the whole family! Dudley ARC: Natter Night Food. Talk -in on 2m and 70cm. Fylde ARS: Top Band Fox Hunting Ar- GEt4CSW at Casteldon School Fete, Bromfords rangements Drive, Essex. Special QSL cards, operation on Chichester DARC: ring PRO HF and 2m - and all the usual fete stands! Wolverhampton ARS: Junk Sale Fylde RS: Top Band Fox Hunt Three Counties ARC: Gold and Silversmiths Wirral DARC: DF Hunt S. Bristol ARC: Radio Interference Service Denby Dale Mobile Rally at Shelley School, Fareham DARC: Discussion on PSUs Skelmanthorpe, Near Huddersfield. Opens Wirral DARC: D W at The Bassett Hound, 11am. Free parking and admission. Trade Thingwall Stands, refreshments, bar plus family entertain- Nene Valley RC: Natter Nite ment. Talk -in S22 and SU8. Details Jack Clegg Three Counties ARC: ring PRO for details 0484 862390 Preston ARS: Annual Quiz with G4DBU 18 Jun Leighton Linsdale RC: Packet Radio by G4ELA S. Manchester RC: Club Quiz Stourbridge ARS: ring PRO for details Dunstable Downs RC: Summer Barbeque at Todmorden DARS: Amateur Satellites by Old Warden G8 UVE Medway ARTS: Junk Sale 19 Jun Biggin Hill ARS: Junk Sale Cambridge DARC: Informal and Morse Class Fylde RS: Top Band Fox Hunt Post Mortem Southgate ARC: Receiver Techniques by Halifax DARS: Surplus Equipment Sale G4 AEZ Wolverhampton ARS: Electronic Music by R. Haverhill DARS: Talk on Radio 'Fox Hunts' Jeavons Harrow RS: Constructing Antennas 20 Jun Three Counties ARC: How A Broadcast Station 9 Jun RSGB 1296MHz Trophy Works 10 Jun RSGB 432MHz Trophy and SWL S. Bristol ARC: Final Preparation for Longleat Elvaston Castle Mobile Rally at Elvaston Coun- Rally ty Park (5 miles SE of Derby on B5010). Fareham DARC: 2m DXing by G3VXM Opens 10 am. Admission Free. Food. Talk -in. Wirral DARC: D Ft W at The Lighthouse, 80 Trade Stands. Bring and Buy. Flea Market. Wallasey Helicopter rides and childrens entertainments. Nene Valley RC: Natter Nite John Robson 0332 767994 21 Jun Chichester DARC: Summer Social 308 ARC: Treasure Hunt Preston ARS: Natter Night Exeter ARS: Inter Club Quiz 22 Jun S. Manchester RC: 160m DF and Barbeque Stratford Upon Avon DRC: On -air Dunstable Downs RC: VHF NFD Planning Dudley RC: Data Transmissions byG4JCP Medway ARTS: The Worked All Britian Awards

HAM RADIO TODAY JULY 1984 by Adrian Keele tection by George Jessop, G6JP Cambridge DARC: Informal and Morse Class Stourbridge ARS: A Look at the Club's Ar- Haverhill DARS: Construction of DF Antennas tifacts for Hunt on 6th July. 17 Jul Biggin Hill ARS: QRP by G4BUE Harrow RS: Special Event Stations Fylde ARS: Discussion of Blackpool Airport 23-24 JunRSGB 1.8MHz Contest visit Worked All Britain 2mr/Ocm Phone Contest 18 Jul S. Bristol ARC: Computer Night with G1 DBH 24 Jun Fareham DARC: QRP from St Kilda by G3 WL Y 1400-2200 UTC Wirral DARC: D Ft W Downstable Downs RC: Car Boot Sale Cheshunt DARC: Visit - ring PRO Longleat Mobile Rally at Longleat Park, near 20 Jul Sutton and Cheam RS: German Wartime Radio Warminster, Wilts. Trade Stands, Bring and by G3IEE Buy, Food and Drink, Camping Facilities, Talk - Haverhill DARS: Club Aerials in. Enquiries G4FRG 0272 848140. Harrow RS: Airborne Radio Capital Radio Venture Day with Amateur Radio 21 Jul Radio and Electronics Fair held by West Kent Show by Harrow RS at Battersea Park, Lon- ARS at Victoria Hall, Southborough, Kent (on don. the London Road between Tonbridge and Tun- Wordsley ARC at Wordsley Carnival bridge Wells). 40 + Trade Stands. Parking, Video games, computers and Special Event (GB2WRA). Station. Open 103D - 1700. Info Dave Green 25 Jun Stratford Upon Avon DRC: Travels In Paradise 0892 28275. by G8 KGJ 22 Jul Anglian Mobile Rally at Stanway School, Col- Dudley ARC: Radio and the Sun by D. Harris chester. Open 1000 - 1700. Talk -in on 2m. 26 Jun Mid -Warwickshire ARS: QRP Info G3YAJ 0206 393938 Wakefield DRS: ring PRO for details Home Counties Mobile Rally at McMichael Wolverhampton ARS: Informal Sports and Social Club, Sefton Park, Bells Hill, Wakefield DRS: ring PRO Stoke Poges, Bucks. Doors open 1100. Trade 27 Jun S. Bristol ARC: VHF FD Briefing Stands, flea market, demonstrations, including Fareham DARC: On-air/natter night radio controlled models, and a real ale tent! Wirral DARC: The Eileen Medley Challenge Cup Talk -in S22 and SU8 DF Hunt 23 Jul Stratford Upon Avon DRC: Constructional Nene Valley RC: Lecture by The Microwave Evening Society 24 Jul Mid -Warwickshire ARS: Fox Hunt and Barbeque Farnborough (Hants) DRS: VHF FD Preview 28 Jun Colchester RA: What Next In Space? by Frank Howe Greater Peterborough ARC: QRP by Rev. George Dobbs, G3RJV Edgeware DARS: VHF FD Briefing 29 Jun S. Manchester RC: Intro to 'Op Amps' by G4 HON Edgeware DARS: Informal and VHF FD Briefing Harrow RS: Informal 30 Jun Three Counties ARC: Barbeque 2 Jul Horndean DRC: On -the -air cheaply by G2DZT Leighton Linsdale RC: ring PRO for details Stourbridge ARS: Informal Todmorden DARS: Radio Treasure Hunt 3 Jul Bury RS: Surplus Equipment Sale 4 Jul S. Bristol ARC: Lecture by the RSGB Fareham DARC: Brewing ATUs by G4GBZ Wirral DARC: Barbeque at Heswall Fylde RS: Blackpool Airport Radio and Radar Cheshunt DARC: Equipment Evening 6 Jul Axe Vale ARC: Visit to TV Transmitter at Stockland Hill S. Manchester RC: VHF NFD Preparations Sutton and Cheam RS: ring PRO for details Haverhill DARS: 2m Foxhunt Harrow RS: Basic Microwaves 7-8 Jul VHF NFD and SWL Contest 9 Jul Exeter ARS: Film Evening Stratford Upon Avon DRS: Homebrewing Tips Leighton Linsdale RC: Quiz at Milton Keynes DRC 10 Jul Mid -Warwickshire ARS: St Johns Ambulance Wakefield DRS: 2m Foxhunt with Pontefract ARS Bury RS: Visit to Emley Moor IBA TV Transmit- ter 11 Jul S. Bristol ARC: 70cms night with G4EIA Farnborough (Hants) DRS: Talk by G3IEE Cheshunt DARC: Natter Nite 12 Jul Southgate ARC: To be arranged Edgeware DARS: Outside visit (t.b.a.) Bury RS: ring PRO 13 Jul S. Manchester RC: The Beginning of the Universe (I) by G4 ROM 14 Jul Harrow RS: Informal 15 Jul RSGB Low Power Field Day Wirral DARC: DF Hunt 16 Jul Leighton Linsdale RC: Lightning and EMP Pro-

HAM RADIO TODAY JULY 1984 11 Wakefield DRS: Pitch and Putt at Holmfield 2 7 Jul Harrow RS: Informal Park 1 Aug Wirral DARC: D Et W 2 5 Jul S. Bristol ARC: HF Night with G4TXW Fareham DARC: On-air/natter nite Will ClubSecretaries please note that the deadline for the Wirral DARC: DF Hunt for G8PMF Award Farnborough (Hants) ARS: Club Station Work-in September segment of Radio Tomorrow(covering radio ac- 2 6 Jul Edgeware DARS: Informal tivities from 3rd August - 5th October '83) is 27th June.

Contacts

Axe Vale ARC Alan Moore 0304 822738 Braintree RS Roger Jones Upottery 468 Bury RS Bryan Tydesley 0282 24254 Cambridge DARC David Wilcock 0954 50597 Chichester DARC C. Bryan 0243 789587 Conwy Valley ARC J. Wright 0492 823674 Cunningham DARC N. Brown 05055 2052 Edgeware DARS John Cobley 30 64342 Fylde RS PRO Lytham 737680 Halifax DARS D L Moss 0422 202306 Haverhill DARS Rob Proctor 0787 281359 Kent Repeater Grp M W Stoneham 02273 69828 Leighton Linsdale RC Pete Brazier 052 523 270 Medway ARTS Andy Wallis 0634 363960 Mid Ulster ARC D F Campbell 0762 42620 Preston ARS George Earnshaw 0772 718175 S. Bristol ARS Len Baker 0272 834282 S. Lakeland ARS Dave Warburton Ulverston 54982 Stourbridge ARS Malcolm Davies 038482 4019 Southdown ARS P. Henly 0323 763123 Three Counties ARC Chris Forshaw 0428 713012 Vale of White Horse ARS Ian White Abingdon 31559 Veralum ARC H.Clayton Smith St Albans 59318 West Kent ARS Peter Reeve 0892 24689 Wirral DARC Gerry Scott 051 630 1393 Worthing DARC Jim Hicks 0903 690415 308 ARC (Surbiton) Dave Hicks 01 399 5487

G3WPO HASSOCKS (07918) 6149 G4KEI 20 FARNHAM AVENUE HASSOCKS WEST SUSSEX BN6 8NS WPO COMMUNICATIONS

Home construction Is on the increase! Or so it appears judging by the punched panel plus hardware kit options. See our previous ads for more details, demand for our products. It really isn't that difficult once you have attempted or ask to be included on our unique OMEGA Mailing List (£1 in stamps). Our that first project - as long as you can solder reasonably well, you are 99% of the newsletter will be sent at intervals(5 issued to date) and keeps you fully informed way towards completing one of our projects. With comprehensive instructions (we on the project, with all known mods, hints and corrections to the published arti- believe the best on the market), clear layouts and high quality pcb's, WPO Com- cles. Some of the modules are suitable f or usewith other designs, in particularthe munications aims at taking out all the uncertainties in building your own gear. All OMEGA PLL VFO will suit 3ZVC/&CLF i.f. designs. It is low noise, highly stable components needed to complete the project are normally supplied, including and coversall Amateur bands in 1 MHz segments and is priced at£108 incall crys- pcb's, pots and wire, Our speciality is HF equipment, but we are broadening our tals (10.7MHz version). The ACTIVE FILTER can be used for any rig needing range to cover other aspects of the hobby, including some pretty unique projects more selectivity and fits in the audio line at low level- 7 switched selectivity posi- which have never been offered before. Why don't you have a goat building some- tion (£16.65). QRP PA (3W) suits 3ZVC/8,CLF I.f. strips also (£21.80). The thing - OSO's are more interesting when you say "running a home brew rig BROADBAND RF PREAMP is very popular on its own and will liven up any HF here..." Design expertise from Tony G3WPO, Chris G4KEI and Frank G4JST. receiver, or can again be used with G4CLF type bidirectional signal designs as it For HF, our most popular kits are the DSB80/160 ORP Transceivers, running 2 uses pin diode Tx/Rx switching (£13.50). watts or more on either 80 or 160M, double sideband or CW and VFO controlled. Moving to VHF, our 2 METRE TALKBOX FM TRANSCEIVER is proving another The basic kit (£37.45) only needs an antenna, PSU (12v) and speaker/mic/key to best seller kit. A cheap way to get on 2 metres, with our 6 channel receiver and get on the air, or we have a case (£23.35 inc hardware) and even a digital readout transmitter designs. Both will work independently of the other, or mate them for option (£24.10) if you want to go the whole hog! There are now over 500 of these Transceive. Rx £39.50, and Tx £32.90, or both together for £68. Crystals not sup- scattered around the world with excellent results. Or, try the UPGRADED DSB2 plied but available from any of the usual suppliers- or go VFO with the new VHF - with enhanced features such as semi -break in keying, active filter, and the Minisynth. Interested in 6 METRES? - then try our 6M to 28MHz i.f. converter ability to run on any single band from 160 through to 15M (£68 inc VFO- state design - complete pcb kit is only £14. Or, if your 2 metre rig is deaf, try our 2M band when ordering) - at the moment the most popular versions are for 80 and PREAMP (very small) at only £5, or the 70CM VERSION for £6.50. 20 metres, and for cw on 10MHz. This MKII version is driven by the MINSYNTH Have you a FREQUENCYCOUNTER- then convert it to a DIGITAL CAPACIT- PLL single band VFO, itself available separately at £29.70. It covers any one ANCE METER! Another unique kit- if you can get at the gate pulse in your coun- band from 160 through 10M, with options for i.f.'s or 9 or 10.7 MHz (state which), ter then try this design priced at £18.20, inc case. 1 pF - 1000's uFs. direct conversion, or a 5-5.5MHz version, useful for second VFO etc Get that G4CLF/3ZVC board up and running at last. Both the DSB2 and the 2 NEW ITEMS THIS MONTH!! SPEECH PROCESSOR - simple but very MINISYNTH come with a polyvaricon capacitor to keep the cost down - for efficient design by G4JST using VOGAD, variable clipping + filtering all the ultimate stability use an air spaced either from your own junk -box or add £7 to the right places. Complete kit only £13.90. +12v operation, suitable for FM/AM/ prices for a top grade Jackson version. Other options are digital displays and a SSB, amateur/CB. case - write for more details. VHF MINISYNTH- by request, our2 METRE PLL VFO KIT- 2MHz BAND Still on HF, another very popular line is our G4DHF TRANSVERTER - unique COVERAGE with options for 144, 133.3 or 1 35MHz or other outputs(up to4 kits which will put your 2 metre multimode rig on to 20/15/10 or 160/80/40 selectable 2 MHz ranges on the pcb to allow fora repeater shift on Tx and Rx). metres, both transmit and receive. You just operate the 2M rig as normal but you Works with our Talkbox for continuous 2M coverage, and should go with have HF transceive operation instead of 2 metres! 2 watts min output will give you almost any other rig that needs direct 2M injection on Tx. and either 9 or plenty of contacts on these bands, and only a 12 v supply.is needed. The kits have 10.7MHz i.f. offset on receive (or Tx). Very stable and easily buildable. Com- everything else included (except metalwork and the multimode!). Either version plete pcb kit with air spaced VFO capacitor ONLY £38.50. Crystals are not priced at £81 including the three conversion crystals needed. Cheaper than an supplied- 1 needed for each 2 M Hz range, full details on ordering rapidly are HF Rig! Hear these working at the Rallies this year. with instructions. Suitable SSB/CW/FM and can be modulated for latter. PROJECT OMEGA is now nearing completion. This is our top -of -the -line Kit More details on request for a 9 BAND HF SSB/CW Transceiver, engineered by G4JST for best perfor- All prices include VAT and post We are MAIL ORDER, or collection by arrange- mance without the frillsIt isn't cheap but does work as many people can now ment (phone Chris between 10am-1 1 am on Brighton 834478 before coming). testify. Professional appearance case available with anodised, screened and Most items ex -stock or allow up to 28 days if not Post Off ice COD over£30. Phone Mon -Fri 10-4pm. See you at the NEC (Stand E27), Woburn, Longleat and New - HF SSB Transceiver 160 or 20m -phone for details. other Rallies. Access-24hour Answering phone 07918 6149.

12 HAM RADIO TODAY JULY 1984 'HRq F \__HORgg athinking man's guide

The idea of going through the that my XYL complained of feeling fer I couldnotrefuse,which municipal bureaucracy for permis- 'caged' whenever she went out to resulted in a three section, heavy sion to erect a HF or large VHF hang up the washing! dutytowerrestingratherin- beam antennaisoff-puttingfor A few weeks later a letter arriv- congruously across my lawn.

many Amateurs. When considering ed from the local Planning Authori- I believe one of the difficulties the various forms, obscure ques- ty. Very tactfully worded.It men- when considering applying for plan- tions and obligatory drawing up of tioned (almost casually) that an ning permission is that there is real- plans, it is little wonder that many erection had been noted within my ly no certainty that you are going to get it. You may put in a lot of work Want to put up a mast but not quite got the nerve? and energy - all to no avail. You are at the mercy of a Committee Steve Voy gives some encouraging advice on coping who areunlikely to know very with the neighbours and the local authority much about Amateur Radioor antennas. I had fortunately kept an of us settle for an unobtrusive ver- grounds for which it appeared no excellent article in the Short Wave tical.Ifwe have an amenable planning permission had been ap- Magazine of a few years ago which neighbour, perhaps a 'Trap Dipole' pliedfor!Stallingfortime, I pointed out that it was up to the ap- with one leg on adjoining land may countered that the erection was in plicant to make every effort to ad- be permitted - always provided fact an aerial mast. I went on to say vance and substantiate his submis- the neighbour on the OTHER side of that it was only temporary and that sion. Merely filling in the required the fence doesn't object. But for a it was not thought sanction would forms could be leaving too much to beam or any other obvious antenna be necessary. Not so, came a reply providence. array,planningpermissionis a shortly afterwards. I dismantled the A start was made on the form must. support and packed away the beam filling.In fact there was not too elements in the garage. much to write in answer to the Going Undercover A few months later a friend questions. I even exagerated the leaving the district made me an of - You can attempt an unauthoris- 'area' of the 'proposed building' to ed erection. You may get away 1.5 square metres, which was the extent of my proposed concrete withitfor a while. But there is always the fear that 'Authority' will base. Two setsofplans were drawn up. One, a street plan of the suddenly presentitselfand ask some searching questions.I made area and the second, at a scale of an unauthorised attempt with two 1:240, showed the proposed site sections of an aluminium ladder layout in the garden with a sketch togetherwithJubilee of the future beam on top of the strapped tower. The requirement called four Clips.Thisgave me a rather precarious 30 feet on top of which copies of the plans - one on linen a length of 2" aluminium tubing or film. This condition was relaxed supported a rotator and TA 33. in my case, probably because no Getting it up was quite a feat and furtherconstructionorbuilding needed the help of a few friends. work was involved. Photocopies Once up it was certainly a thing of were obtained at the local library beauty to me - especially when for 10p each. the sun caught the aluminium sec- tions. The statement that you can First Hurdle keep a string of sphagetti upright if you guy it correctly was proved in A disadvantageI knew would my case. Unfortunately, the garden be thatI was living in a Category was thusliterallycovered in 'B' house of 'Special Architectural galvanised, steel guy wires - such Steve's Ladder Mast Interest'. Ivisited the Planning Of -

HAM RADIO TODAY JULY 1984 13 fice to discuss my project and was tion". The end result was around told I could submit a letter to the 60:40 in favour of supporting my Committee toelaborate on any application with two abstentions! points I felt may be relevant. I Three young female students were thought about this for a while and - in "full support" but a retired lady then came up with: doctor had reservations and opted a) The antenna would be used for the alternative. I lifted one dear purelyforAmateurRadio little retired lady so that she could operations; no commercial in- see over her garden wall to where terest was involved. my antenna would be. Full support. b) The erected mast was to be in a I had asked allif they remembered semi -commercial area. Nearby my previous ladder mast but none telephone poles, power cables could recallit. The climax came and three storey buildings by when I has almost finished my can- far overshadowed it in height. vassing and knocked on the door of c) The rotating beam on top of the one of my immediate neighbours.

mast would be lower than prac-. "Hello," I beamed, in what I ticallyallTV aerialsinthe hoped was an engaging smile. "It's vicinity. about my aerial.I wonder if you'd d) Thesupportingmast was care to support . . . . "

telescopic in design. The anten- "NO I WOULD NOT," he na could well be lowered to rasped and quickly shut the door. around 10 feet (and thus out of general view for much of the Facing The Music year. e)A GPO engineer had recently I realisedI had a problem here. conducted tests on asimilar A next door neighbour must surely aerial (my ladder mounted job) count for at least six more remotely

which proved that my equip- sitedresidents.Undeterred I ment was free from spurious assembled my papers, plans and radiation out of the Amateur statements together and took them Bands. No complaints ofin- Voy antennas in close-up inpersontothelocalPlanning terference to domestic radio or on either side of me, about ten Authority. TV had been received. houses opposite me in the street and A week later a Solicitor's letter All the above was admittedly of lit- half a dozen buildings in the parallel arrived.Itwas quitecourteous tlesignificance to the dedicated streetthatoverlooked my rear (they usually are) but stated they conservationalist on the Commit- garden,whichincluded a few would be objecting (on behalf of tee. But I thought it was plausible Private Hotels. The occupants were the aforementioned irate enough to sway any borderline a mixed bag, mainly business prac- neighbour) to the proposed anten- cases in my favour.I purposely us- tices, consisting of Architects, Ac- na erection on the grounds of TV edthe word'mast'insteadof countants, and Medical Specialists. interference.I was furious.I phon- 'tower'- why frightenthe A few private occupants made up ed the advocates but no one would speak to me. I left a message say- uninitiated? the total. Calling on each in turn, I presented two versions of a letter ing that I strongly objected to the Going Visiting for their signature. One purported allegation and challenged them to to "fully support me in my applica- provide dates/times and types of My nexttask was tovisit tion" and the other professed to interference.I was convinced this neighbours extending to six houses "have no objection to my applica- was a red herring. I imagined the complainantvisitinghissolicitor The present set-up viewed from afar and being comforted with, "Don't worry sir - we can always infer that hewillinterfere with your television." What really concerned me was that a similar letter would almost certainly have been sent for the attention of the Planning Com- mittee.

I deliberated abit. I did not want to get into a personal battle with my neighbour but feltI had to defend myself against what I was sure was a wild allegation. Even- tuallyI sent a letter to the Commit- tee stating I had reason to believe a complaint hadbeen madeas regards my causing interference to

14 HAM RADIO TODAY JULY 1984 The awaited letter finally came TV. I was able torefer to my Solicitors with the idea of extrac- previous submission that no un- ting some reaction to my counter two weeks later. Success! Planning wanted transmissionshadbeen objections.I was informed that the Permission had been granted for 2 discernedbycompetent GPO person dealing with it was ill. years. The actual typewritten com- ment ended with the condition that Engineers. I said that if in fact he I contacted the Planning Office was suffering from TVI he had not a few days after the meeting of the "the said mast is removed on or reported it to the GPO (a wild guess Committee and was told no deci- beforetheexpirationoftwo on my part) and it certainly was not sion had been made yet. My ap- years . . ." This is not as ominous originating from my equipment. plication had been discussed but as it sounds. Just before the expiry A few days laterI phoned the deferred date I simply reapply and ask for a further two years. So far the exten- sion has always been granted.

Charge In Legislation

Legislation has since changed in that, nowadays, a form must be completed whereby you state you haveadvised yourimmediate neighbours of your intention. They do not have to agree; it is sufficient to make a declaration that you have made them aware of your plans. No doubt if they feel strongly enough about it the onus is on them to in- spect your plans at the Municipal Offices and make any objections formally. I am now fortunate in hav- ingobligingneighbours who unanimously last time returned the form to me endorsed "OK with me." The processisreallyquite straightforward. The initial forms seem rather overpowering but real- ly it is the more involved 'Applica- tion for Building Warrant' - not normally necessary fora tower siting - where the procedure ap- pearstobecome morecom- plicated. Local Planning Authority staff were always most helpful. I suppose you could say it is their job to be so but theirreplies were always friendly and considerate - even if they perhaps thought they were dealing with a crank! Shouldtheapplication be disallowed, a reasonis given - "conflicts with the amenity of the neighbourhood" is a good one! If the applicant feels strongly enough about it, he has recourse to appeal to the Secretary of State within six months. I hope this narrative will give a little encouragement to any aspir- ing tower erectors. Don't assume the cards are automatically stacked against you. With a little thought and effort you may be able to steer your application along theright path - even if you know for certain you have at least one strong objec- tor!

HAM RADIO TODAY JULY 1984 15 Cirkit.Anew name This year Ambit will stop being Ambit. And Computer Products A complete range from Connectors to become Cirkit. Board Level product Cirkit is more than just a change of name. It means a better service for you. Faster delivery. A bigger range of the best and latest products with well over 10,000 different items available. Everything for the home and industrial user. A whole new Cirkit range of constructional C12 Computer Cassette 21-00012 0.55 kits, graded for the student, expert and BBC to Centronics Printer 03-10019 7.25 BBC to 25 way D Male 03-10021 4.50 enthusiast. 25 way D Socket 10-25200 1.90 Modules to build for everyone. 25 way D Plug 10-25100 1.30 Cover for 25 way D 10-25322 0.93 Cirkit is a go ahead company that believes in 20 up Eprom Eraser 40-82100 31.25 Z80 A Industrial Controller 40-82000 49.95 giving service to its customers. 6802 Industrial Controller 40-68020 49.95 6502 Industrial Controller 40-65020 49.95 There's a technically skilled staff to help you. Z8 Basic/Debug Controller 41-00904 50.00 We keep in touch with the manufacturers Nicad Batteries & Chargers and we know what's going on. Minimum life 600 (300 PP3 size) full charge/discharge cycles. Batteries As soon as new products are available, Cirkit charged from a constant current source 411 only. All batteries are supplied only with a has them. residual charge and should be charged Cirkit means a bigger catalogue. A better before used. 1-9 10-49 company to deal with. AA 1.2V 500mAH 01-12004 0.80 0.74 C 1.2V 2.2AH 01-12024 2.35 1.99 And a wider than ever range of products 'D' 1.2V 4.0AH 01-12044 3.05 2.85 PP3 8.4V 110mAH 01-84054 3.70 3.50 that's growing all the time. CH1/22 PP3 Charger 11mA for 16 hours 01-00159 4.30 For you, Cirkit means a bigger stock and CH 8/RX Multi -purpose Charger better service. 01-02204 9.40 Will recharge AA, C, D and PP3 size cells For further information send for our latest with automatic voltage selection. Will recharge following combination: 6x D, catalogue or visit one of our three outlets at: 6 xAA, 6xC, 2xPP3, 2xD+2xC, 2xD+2xAA, 2xD+1xPP3, 2xC+2xAA, 200 North Service Road, Brentwood, Essex, 2xC+1xPP3, 2xAA+1xPP3. CM14 4SG; 53 Burrfields Road, Portsmouth, Battery Adaptor 01-12001 0.96 Sold in pairs: one to convert AA size to C Hampshire, P03 5EB; Park Lane, Broxbourne, size and one to convert C to D size. Both may be used together to convert an AA to D Hertfordshire, EN10 7NQ. size. To: Cirkit Holdings PLC, Park Lane, Broxbourne, Hertfordshire. Semiconductors I enclose 80p. Please send me your latest catalogue and 3 x £1 discount vouchers! Linear IC's If you have any enquiries please telephone us on Hoddesdon (0992) 444111. LM301ANDIL version 61-03011 0.44 Name LM308CNDIL version 61-03081 0.65 LM311CNPopular comparator 61-003110.46 Address LM324 Low power quad op amp 61-032400.67 Telephone LM3 319N Low power quad comparator61-033900.68 LM346 Programmable quad op amp61-003463.72 Area of Special Interest LF347 Quad Bi-FET op amp 61-003471.82 LM348 Quad 741 type op amp 61-034801.26 LF351 Bi-FET op amp 61-035100.49 LF353 Dual version of LF351 61-035300.76 LM380N IW AF power amp 61-003801.00 NE555N Multi -purpose low cost timer CirkitBigger Stock. Better Service. HRT7 61-055500.45 blidir 4roolr 1 Att /DI forabetter service. NE556N Dual version of the 555 61-055600.50 BC309 Complement to BC239 58-003090.08 Monolithic Capacitors uA741CNDIL low cost op amp 61-07411 0.22 BC327 Driver/power stage 58-003270.13 Pack of 3 uA747CNDual 741 op amp 61-074700.70 BC337 Driver/power stage 58-003370.13 In 04-10204 0.39 uA748CN741 with external frequency MPSA13 NPN Darlington 58-040130.30 10n 04-10304 0.42 comp 61-047800.40 MPSA63 PNP Complement to 100n 04-10404 0.45 HA1388 18W PA from 14V 61-013882.75 MPSA13 58-040630.30 TDA2002 8W into 2 ohms power amp 61-02002 1.25 J310 JFET for HF-VHF 59-023100.69 Low Voltage Disc Cermaic ULN2283 1W max. 3-12V power amp 61-022831.00 J176 JFET analogue switch 59-021760.65 Pack of 5 MC3357 Low power NBFM IF system 3SK51 Dual gate MOSFET-VHF amp60-04051 0.60 In 04-10203 0.20 and detector 61-033572.85 3SK88 Dual gate MOSFET-Ultra lo 10n 04-10303 0.20 ULN3859 Low current dual conversion noise 60-040880.99 NBFM IF and detector 61-038592.95 TIP31A Output stage 58-15031 0.35 Polyester (C280) LM3900 Quad norton amp 61-390000.60 TIP32A Complement to TIP31A 58-150320.35 Pack of 3 LM3909N 8 -pin DIL LED flasher 61-390900.68 VN66AF VMOS Power FET 60-020660.95 10n 04-10305 0.18 KB4445 Radio control 4 channel ZTX3866 E -line version 2N3866 58-038660.45 47n 04-47305 0.24 encoder and RF 61-04445 1.29 IN4001 Rectifier diode 12-400160.06 100n 04-10405 0.24 KB4446 Radio control 4 channel 1N4002 Rectifier diode 12-400260.07 receiver and decoder 61-044462.75 470n 04-47405 0.51 IN4148 General purpose silicon 12-414860.05 ICM7555 Low power CMOS version of luF 04-10505 0.66 timer 61-755500.98 Silicon Controlled Rectifiers ICL8038CC Versatile AF signal generator R F Components with sine/square/triangle BRY55-100 100V .8A 52-551000.50 OPs 61-080384.50 C106D1 400V 4.0A 52-001060.70 TK10170 5 channel version of KB444561-10170 1.87 C122D1 400V 8.0A 52-00122 1.45 HA12002Protection monitor system for amps, PSUx, TXs etc 61-12002 1.22 3mm Diameter LEDs HA1201783dB S/N phono preamp V178P Red 15-017800.15 0.001% THD 61-120170.80 V 179P Green 15-017900.16 MC14412300 baud MODEM controller V 1 80P Yellow 15-018000.18 (Eduro/US specs) 61-144126.85 5mm Diameter LEDs CQY4OL Red 15-104000.12 CQY72L Green 15-107200.15 CQY74L Yellow 15-107400.15 Filters Infra -Red LEDs CFU/LFB CFW/LFH SERIES CQY99 Emitter 15-109900.56 Miniature 455kHz filters. 1/P and 0/P BPW41 Detector 15-30410 1.51 impedance 2K. Tri Colour LED -6dBW -40dBW V518 Orange -Green -Yellow 15-051800.60 LFB6/CFU455H 6kHz 18kHz 16-45512 1.95 LFB12/CF1J455F 12kHz 26kHz 16-45515 1.95 Capacitors LFH6S/ CFW455HT 6kHz 14kHz 16-45525 2.45 LFG12S/ Microprocessor & Memories CFW455FT 12kHz 22kHz 16-45528 2.45 Z80A Popular and powerful CFM2455A Mechanical IF Filters for 8 -bit CPU 26-184003.40 455kHz 19-45530 0.77 Z80AP10 2 port parallel input/output 26-184202.95 Z80A CTC4 channel counter/timer 26-184302.90 Crystal Filters 2 Pole Types Z8671 Z8 Micro comp. and Basic 26-0867117.50 10M15A 10.7 Centre Freq. 20-10152 2.10 6116-3 16K (2kx8) CMOS 10M08AA 10.695 Centre Freq. 20-11152 3.49 RAM 200nS 26-361166.68 Z6132-6 32K (4kx8) quasi Inductors RAM 350n5 26-0613215.00 We offer the complete Toko range of fixed 4116-2 16K (16kx1)150nS 26-24116 1.59 and variable inductors. Over 500 coils from 2764 64K (8kx8) 450nS 26-027649.50 audio to V.H.F. See catalogue for details. 2732 32K (4kx8) 450nS 26-027325.70 Soldering Irons (Antex) Voltage Regulators Aluminium Electrolytics Radial PCB 7805 5V lA positive 27-780520.40 Mounting CS240 Iron 240VAC 17 Watts 54-22300 5.20 7812 12V lA positive 27-781220.40 Pack of 4 XS -240 Iron 25W 240V High heat capacity 54-22500 5.40 7815 15V IA positive 27-781520.40 10u 16V 05-10606 0.24 7905 5V IA negative 27-790520.49 SK6 Presentation pack of one 47u 16V 05-47606 0.28 XS -240 with ST4 stand 54-22510 7.20 7912 12V lA negative 27-791220.49 47u 25V 05-47607 0.28 MLXS Handy 12V 15W soldering 7915 15V lA negative 27-791520.49 470u 6.3V 05-47705 0.36 iron complete with Transitors 470u 16V 05-47706 0.48 crocodile clips and solder 54-20004 5.60 BC182 General purpose 58-001820.10 BC212 General purpose 58-002120.10 Tantalum Beads BC237 Plastic BC107 58-002370.08 Each Please add 15% VAT to all advertised prices BC238 Plastic BC108 58-002380.08 luf 35V 05-10501 0.18 and 60p post and packing. Minimum order BC239 Plastic BC109 58-002390.08 10uf 16V 05-10601 0.28 value £2 please. We reserve the right to vary BC307 Complement to BC237 58-003070.08 47uf 6.3V 05-47601 0.45 prices in accordance with market BC308 Complement to BC238 58-003080.08 47uf 16V 05-47602 0.92 fluctuation. tf Haveonehandle... reviewing the u ELE Nou

Currentlypricedat£169,the the FT208R and 708R. Simplicity depressed, reduces the power out- FT203R is Yaesu's new 'handle' of operation is the watchword with put to some 0.3W), the BNC RF 2m transceiver.Considerably the '203R. On the left hand side of output socket, the three switch smaller than the FT208R and with therigisthe PTT control, and 'thumbnail'controlsforsquelch around the same power output above this, the toneburst push con- and audio volume (the volume con- (although the '203R will give 3.5W trol,both with dimpled surfaces trol also doubling as the transceiver on/offswitch),twominiature Thinking about a 2m handheld? Steve Ireland, sockets for either the accessory G3ZZD, took Yaesu's new baby for a walk. headset/microphone (YH2) or the speaker microphone (MH-12A2b) with the accessory FNB-4 12V enabling slip -free operation. On the and, finally, a small square push- NiCad pack), the FT203R offers right hand side is a similar square button, which adds an additional straightforward FM simplex and button control for illuminating the 5kHz to the frequency selected by repeater operation. miniature'S'/RFPower output the thumbnail frequency selector. The frequency selection on the meter, which is mounted on the top This control enables the election of '203R isby thumb wheel swit- of the transceiver. As well as the odd channels, ie 144.775 as the ching, easier to manipulate on the meter,thetoppanelcarries a thumbnail can only select to the move than the Keypad offered on high/lowbutton(which,when nearest1 0kHz. 144.775MHz is thus displayed as 577 - with this Alison listening on S20 with the FT203R and YH2 headset ' + 5kHz'button depressed. The necessityofafourth thumbnail switch is thus avoided, which, after all, is only going to be set at either 5 or 0. Set into the left hand corner of the top panel are two LEDs. The green LED indicatesthatthe receiver squelch has opened: if the squelch is set very low - so that the ambient noise breaks squelch - the LED will light, in addition to lighting when astationisbeing received. The hand book says that this is useful when monitoring in a noisy environment as a 'busy chan- nel' indicator - which is probably true. However, the author is moved to speculate that if the environment is that noisy, the operator will need at least to don the YH2 headset mic or move to a quieter environment before any operation can be done! On the rear of the '203R, just above the unit belt clip, is a small squarepanelcontainingtwo

18 HAM RADIO TODAY JULY 1984 miniature three -position slide swit- lumination on the top panel rather, ches. One of these is for selecting than in the meter would have been repeater/reverse repeater/simplex bettgr. operation, labelled '-600', 'SIMP' VOX operation was straightfor- and' + 600'. The lower switch ward, both the 'high' and 'low' selects VOX switching when using positions fulfilling the promises in the YH2 headset/microphone: two the handbook. However, I did feel settings are available, HI and LOW. that the 'attack' of the VOX cir- The HI positionisfor quiet en- cuitry was slower than I would vironments,providingmaximum have liked, particularly on the low sensitivity of the VOX circuitry, position, triggering often not occur- whilstthe LOW positionde- ing till well into the first syllable. sensitizes the circuitry in order to prevent'triggering'fromex- The Verdict Top Panel traneoussounds(motorbikes, slammingdoorsetc)when ternal mic and the YH2 headset. If you want a basic 2m lightweight operating in a noisy environment. With many handportablesthe FM 'handle', then this could be the Both of the switch levers are very audio quality and quantity is often rig for you.It lacks the scanning low profile, in order to prevent the noticeably better with an external and memory facilities ofit'sbig operator from inadvertantly chang- mic, but the '203R proved itself a brother,the FT208R. However, ing the switch selections, a nice creditable exception in this case. frankly, as far asI am concerned, touch. No real difference was noticed bet- this is really extra 'icing' and not ween the Y H2 and the internal mic particularly useful if you are to use Well Built? by the statons I contacted, who all therigforthepurposeof a reportedtheaudioqualityas sophisticated'walkie-talkie'- Withhandheldtransceivers "good". which is what most 'handles' and ruged construction is a must. The The FT203R was then taken on 'portables' are intended for, and us- battleshipgrey moulded -plastic a prolonged hike, housed in the pro- ed as. case of the '203R looks as though tective soft vinyl case supplied The lightness and compactness it will stand a few hard knocks - with the rig. Operation with the rig ofthe '203R mitigates against althoughI was not moved to test inside the case is possible but Idid dropping the rig through not get- this out! The transceiver PCB is sur- not like this, feeling that the PTT tingholdofitproperly.People rounded by a U-shaped chassis, and toneburst buttons were dif- often forget to put their hands which shouldalsohelpinthis ficult to 'feel' through the case. This through the wrist straps of handies respect. was possibly due to my lack of in the excitement of hearing so- I have recently used the Yaesu familiarity with the '203R and was meone comingthroughand FT708R,the70cmportable not felt to be a serious problem. wishing to reply quickly. Well,I do transceiver and identical twin to Thus, most operation was done anyway and this can sometimes the '208R, and the construction of with the rig 'naked'.If you have leadtonear tragedy . . . By the the '203R seemed somewhat less large fingers and enjoy operating in way, the '203R has a good wrist solid thantheaforementioned. a downpour, the FT203R might not strap. However, the other consideration be the rig for you. That being said, I Notdissiniiliar in sizeand of construction with equipment of don'tknowofanyhandheld specificationtotheBelcom this kind is weight - and you are transceiver which is too good in LS2OXE, the '203R packs rather a less likely to get a tired wrist with this latter respect. larger punch (2.5W against 1W) the '203R than the '208R, the lat- Operation on the move was butcostssome £40more. ter being almost some 50% heavier fairly easy and, with familiarity, the However, with the optional FNB-4, than the former. PTT and toneburst were easy to the '203R will give 3.5W (!) - The circuit board of the '203R operate with a one/two movement which can be usefull as the small is well laid out without too much of the fingers of the right hand, us- antenna on most 'handies' usually cramming of components and the ing the index finger to operate the means that the transmit capability quality of construction seems up to toneburst. Despite my poor loca- is often more restricted than the the usual Yaesu standard. tion, sprawled in a grassy hollow receive. On the other hand, the somewhere northofEdgeware, FNB-4 is another £36. Mind you, Operating The Beast Middlesex,withthetransceiver you really need NiCads anyway for beside me on the ground, most of regular portable operation - and The FT203R fitted perfectly in- the London repeaters were receiv- that means shelling out a lot extra

to the small but perfectly formed ed at good strength. on any rig. And so on . . . and so hands of the author. Even the most If you are a night owl, the lamp on. You makes up your mind what dainty of hands should not find this inside the top mounted meter is you need from a portable, takes rig too much of a handful. useful for checking the power out- your choice and pays the money. A number of contacts were in- put (and, thus, your battery condi- As far asI am concerned, if you itiallymade throughthelocal tion!).Unfortunately,thelight want a 'handie' this one is pretty repeater GB3NL - sitting at the kit- thrown out doesn't quite reach the OK. OK? chen table. Reports on the modula- frequency selector and frequency The author would like to thank SMC of tion were good, both using the in - checking requires a flashlight.II- Southampton for the review sample.

HAM RADIO TODAY JULY 1984 19 SAVE £4.25 by receivingaFREE magazine binder whenyou subscribe to......

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Some time ago it was impossible to beenleadwithout encountering is 10 uV in on seventy producing obtainpowertransistorsthat these devices may be surprised to 25 db quieting. This may seem would work on the 70cm amateur learn that quite a high efficiency lousy to your keen UHF type but is band. As a result varactor diode can be obtained, typically ten watts quite adequate for local repeater (or simplex) work. As a rough guide to someone who is contemplating this Hugh Allison, G3XSE, describes a cheap and novel idea, a 'proper' 70cm receiver con- way to get going on 70cm. nected to the intended aerial should receive the intended repeater at about S7 for you to use the techni- 'triplers' enjoyed a fair degree of of 2m RF will yield six or seven quelieifyou canreceivethe popularity amongst the solid state. watts of RF on 'seventy'. I digress, repeater at S7 on purpose built enthusiasts.Althoughtheystill however. Why doesn't the tripler 70cms equipmentitshould be represent an easy way up onto the do anything on receive, you may perfectlycopyablewiththe band on the transmit side, especial- wellask.Well,thetripleronly 'tripler'). ly for FM, left triples due to the incoming RF problem of obtaining a converter or energy on two metres, on receive A Little Arithmetic receiver for listening. This article is there isn't any RF input so nothing dedicated to overcoming this little happens. My idea was to inject The first concept to be grasped problem. some 288 MHz and see what hap- is that mixing in a varactor does not pens, and it works; you get a crude produce a 'normal'transverter. Varactor Workings receive converter. Most transverters mix on receive and transmit, thus if you increase Not many people know that a Receiver Degradation your frequency on 2m by 10 KHz varactor 'triples' effectively by mix- your receive and transmit frequen- ing. An idler circuitina typical The normaltwometre cies on 70cm increase by 10 KHz. 'two' to 'seventy' tripler will be transceiver in my shack is a badly Here your receive frequency will in- tuned to 288 MHz. The incoming abused TRIO TR9000 which will crease by 10 KHz but your transmit two metre signal (144 MHz) mixes give about 25 db of quieting for 1 frequency will go up by 30 KHz. with 288 MHz to give resultant uV ofsignal. The best I have That is why this is really a single 432 MHz. People whose life has managed to achieve with this idea channel device, althoughifyou wade throughthefollowing mathematics you will be able to see a two metre II 4-12V that anyone with C8 transceiver with a non-standard L3 rrin Ou1 repeater mode can also work other R2 47k TO IDLER channels. In my area the local seventy repeater is GB3SV on RBO.This NOTE: 01 01 IS 2N2369 OR SIMILAR receiveson 434.6MHz and L3 TO RESONATE AT 57 MHz 7 TURNS ON 1/4" FORMER transmits on433.0 MHz. COUPLING LOOP 1 TURN XTAL C5,." R2 Remember that is the repeater for- SEE TEXT = 30p7'" 47k R4 1C7 120R mat; an accessing station does it round the other way round. We thus have to provide a transmit Fig. 1Suitable crystal oscillator for providing injection to 'tripler' to signal on 434.6 divide by three - give receive capability which equals 144.866 MHz. Sim- ple so far? Well, we are already up D HAM RADIO TODAY JULY 1984 21 FIN @

L3 = NEW COUPLING LOOP 1 TURN 3/4" DIAMETER L3

L2 cx L3

C2 O 3 x F OUT

288 IN C3?

/7/// Fig. 2 Classic Varactor Tripler circuit. 'Triplers'may often be found in the secondhand columns of the radio magazines. If no luck there you could try asking around in your radio society. Someonesomewhere will

doubtless have one gathering dust. . .

against a snag; most rigs put up an evolved over the years is shown in Obviously a preamp could be accessing tone only when placed in Fig.2 . The coil of interest isL2, used in front of the transverter, but the repeater mode - which means which fairly often runs from one the switching involved spoils the that you either dial up another 600 side of the small diecast box, in simplicity of the idea - and the at- KHz (The 2m receive/transmit off- which these triplers are normally traction of essentially using the 2m set is receive 600 KHz higher at the constructed, to the other. It is nor- rig normally, I think. There have, accessing station; for 70cm the of- mally a one turn loop of half or surprisingly, been no reports of any fset is transmit 1 .6 MHz higher!) or three quarter inch in diameter. Hav- hetrodynes being produced, which you use a non-standard repeater ing identified the idler circuitry the I had expected due to the two lots shiftof 0KHz,ietransmit and decision has to be made asto of 288 MHz at the diode when receive on the same frequency. I whetherthe'modification' (a transmitting. This may well be due shall only work this latter example source of 288.134 MHz) is going to the lower level of the receive since it will be of more interest to to be incorporated within the body 288 MHz compared to the transmit those owning a crystal controlled of the tripler itself. one. 2m rig. My original attempt to try out I hope you have as much fun Sothe 2mrig is setfor the idea was made using a free run- with the idea as I had. It's in the 144.866transmitandreceive. ningoscillatortoprovidethe true spirit of amateur radio, getting Now letusconsider the 70cm necessary 288.134 MHz injection. something almost for nothing and receivepath.Here we want to The energy from the generator (A making something work as it was listen to 433 MHz but are tuned to Hewlett Packard 608 giving about never intended to! 144.866. Subtracting one from 700 mV into 50 ohms) was coupl- theothergives 288.134 MHz ed via a quarter inch diameter one which is the frequency we have to turn loop, the loop being pushed in- Components Listing inject into the idler circuit of the to place and then held there by tripler. simply replacing the lid of the box. Resistors If you want to make the unit self- R2 47k 1/8W Modifying the Tripler containedthesimplecrystal R3 10k 1/8W oscillator ofFig.1 can be built-in, R4 120R 1/2W It is not my intention in this arti- though takecarenottoplace cle to give a step-by-step, hole -by- anything too close to any of the Capacitors hole description of how to build a original components! Alterntively C5,6 30p trimmer 70cm varactor tripler. Some people the oscillator could be mounted ex- C7 1000p disc may well have one immediately to ternal to the box; it's up to you. Ob- C8 0.1u disc hand, either home made or one of viously the frequency of the crystal the excellent Microwave Modules hastobe worked outbythe Semiconductors ones, which are often available se- guidelines shown above, and a TR1 2N2369 or cond hand quite cheaply. The idea crystal of one fifth of the required similar of this article is to resurrect an arti- frequency (about 57 MHz) should cle many people have consigned to be obtained. The people with non- Miscellaneous the junk box and of which there is a standard repeater shiftrigs (and L3 to resonate at 57MHz. 7 reasonably plentiful supply already good mathematics!- Ed.) may be turns on 1/4 inch former. Coupl- in existence. For ease of identifica- able to use a 'gash' crystal to hand ing loop 1 turn. Crystal (see tionthecircuitdiagramofthe by dialing up some odd receive fre- text). almostclassiccircuitthathas quencies.

22 HAM 1:1,4010 TODAY JULY 1984 A Guide to

Beforebeginningtodiscuss These errors this method of communication let then, are detected me tell you what the letters A, M, by encoding each T, 0, R mean. The first two stand of the 32 standard for 'AMateur' and the 'TOR' in- teleprinter characters dicates 'Telex Over Radio'. TOR as a pattern of 4 was the name decided upon by Mr marks and 3 Van Duuren, a Dutch Posts and spaces. There are Telegraphsengineer,inthe 35 posible 1960s. He was endeavouring to combinations find a means of improving the quali- of 7 bits but the ty of copy on HF radio teleprinter remaining 3 are used as circuits so that they could be con- special control characters. nected directlyinto the interna- You may remember that in my first gets tional Telex network. article on RTTY, (Ham Radio Today received correctly or that it is Ken Michaelson, G3RDG, looks at AMTOR - the corrupted beyond recognition. So inpracticetherearevery few ultimate in keyboard communication. undetected errors.' Thisautomaticrequestis I am sure that readers will ap- May 1983), I talked about the achieved with the two stations preciate that errors do occur when 'Baudot Code' or 'CCITT No 2 In- working in an accuratelysyn- you have QSOs over the air using ternational Teleprinter Code'. That chronised quick -break mode. When RTTY and very frustrating they can is a 5 unit code but in the first and operating in mode 'A' as described be too. The result is,of course, best known version of the AMTOR above,thetransmittingstation garbled copy, and thisisnot of system, called 'ARQ' (automatic re- breaks the message down into great help when trying to discuss, quest for repeat) or mode 'A', in- blocks of three characters each for example, the subleties of the rig steadof 5 databits, 7 are and, after a block has been sent, you are using. transmited. Three bits are of one the transmitting station switches to Mr Van Duuren recognised this polarity and four of the other, mak- 'receive' and waits for a reply from problem and rather than try to im- ingitineffect, a 7bitcode. the other end. If the receiver has prove the quality of the copy by Therefore, at the receiving end it is copiedtheblockcorrectlyit conventional means, such as im- possibletodetectwhether a responds with a single provements to the antenna system character is valid or not by counting 'acknowledgement' character, and orincreasing the power of the the number of 'Mark' bits init.If the transmitting station proceeds transmitter etc, he decided on a there are exactly 4 'mark' bits, then with the sending of the next block scheme whereby the errors would the character is treated as valid; if of three, and so on. If, however, be detected through a system of not, then it is rejected and signalled the other end has not received the 'logic' after the demodulation pro- back to the transmitting station block correctly,itsends back a cess and then corrected by repeti- who thenrepeatsthebad 'repeat' request, and the transmit- tion. This 'logic' system is a system characters,severaltimesif ting station sends the same block in which the values of the variables necessary, until the receiving sta- again. This procedure continues in- are simply restricted to two possi- tion gets them correctly. This is not definitely until the particular block ble'truthvalues'. These values completely foolproof,of course, is copied by the receiving end, and may be represented by the digits because itis possible for two or then,and only then,does the '0' and '1' and therefore can be ap- more bits to be corrupted and still transmitting station move to the plied to the BINARY logic of com- leave a net result of 4 Mark bits giv- next block of text. puters. 'Mark' or 'Space', 'Plus' or ingtheappearanceof a valid 'Minus' volts etc can amount to the character.This does sometimes In Synch' same thing. In this case it is 'Mark' happen, but it is much more likely as against 'Space'. that either a block of characters It is the use in its circuitry, of N HAM RADIO TODAY JULY 1984 23 _ ,, .,, ,: Inside the ICS AMT -1 purpose built AMTOR unit- used widely across the globe and manufactured in the UK to boot! 'synchronous'asagainst'asyn- character. Clever, eh. In AMTOR, Start or Stop bits, each character chronous', transmission ofserial synchronisation is detected either followingimmediatelyafterthe data which gives AMTOR 'A' such by successfully receiving a known previous one. The transmitting sta- an advantage over conventional combination of IDLE characters, or tion sends the repeat regardless, so RTTY. Instead of a 'start' bit at the by receiving a pre -determined- four no 'request for repeat' is sent back beginning of each character, as in character SelectiveCall(Selcall) by the receiving station. This mode normal RTTY, the receiving end is code. By using this method of sen- ismost useful whereitisnot kept in sync' by the transmission of ding messages, virtually error -free necessary to have a reverse link, a 'start' code at the beginning of a copy is obtained at the receiving such as when broadcasting. In fact, transmission.Inorderthatthis end no matter how much QRM it is similar in use to normal RTTY in method should work, the speeds at comes up on the frequency. that it is 'simplex' operation. First each end must be far more accurate station'A'transmitsandthen than in an 'asynchronous' system Mode `13` passes the transmission over to and therefore it is necessary to use station 'B', who, when he finishes crystal oscillators rather than the In the second version of the his transmission, passesitback mechanical governors which were system, called 'FEC' (forward error again to station 'A'. Its efficiency is described in my RTTY articles. At correction) or Mode 'B', each 7 ele- not as high as ARQ, but never- no time does the transmitting sta- mentcharacteris transmitted theless it is a considerable improve- tion send a continuous idle Mark or twice, thus allowing the receiver ment over traditional RTTY, (some- Space tone. to, as it were, get a second bite at times to a factor of 10). A question You might well ask how does the cherry if the first one was spoilt which might occur to you at this the receiving station know when a byinterference.To reducethe point,is how does the receiver character startsifthereare no possibility of a single burst of in- know which is the first copy of the 'Start' bits. Well, the answer is that terference corrupting both copies character and which is the second. the receiver examines the incoming of the character, the copiesare Inmode'B'two differentIdle stream of bits looking for a par- separated in time by 350 mS, that charactersareused, one being ticular pattern of consecutive bits is, 5 character times, therefore giv- transmitted in a 'time -slot' which which correspond to a known syn- ing the receiver a greater chance of would normally be used by the first chronisation character. When this copyingit.The speedis always copyof a messagecharacter, pattern is recognised, the receiver 100 Bauds; that is, each bit time is (time -slot No. 1 say), and the other knows that the nextbit which 10 mS, so that it takes 70 mS to being transmitted in a time -slot us- follows is the first bit of the next send a 7 bit character. There are no ed by the second copy of the

24 HAM RADIO TODAY JULY 1984 character (time -slot No. 2). These clause permitting data transmis- does the system spring into life.It Idlecharactersaretransmitted sions on frequencies above 144 is possible, therefore, to leave the when no message characters are MHz, but in the following year with receiver running for long periods being sent, and are also inserted at the help of the late Roy Stevens, withoutprintingordisplaying regular intervals, to give the receiv- G2BVN, permission was given by anything until someone calls you. ing station a chance to get into the authorities to use AMTOR on This is a very different state of af- 'sync'. the HF bands. In 1980, the IARU fairs to the working of 'Autostart' Region 1 conference adopted a in conventional RTTY. I used to try W1AW On AMTOR resolution urging all member coun- Autostart in my RTTY set-up on 2 tries to press for similar permission meters, and I must confess that it from theirrespective Posts and was not a great success. I suppose It might also interest you to Telecommunications authorities. it was because of the fact that know that News Bulletins have In the beginning the only way some operators use a speed of beenregularlybroadcastfrom to get on AMTOR was to write your 45.45 bauds and others use 50 W1AW, the ARRL headquarters own programtorunon a bauds, so that if you have set the station, in RTTY, ASCII and AM - microprocessoror 'home-brew' gear to receive 45.45 bauds and TOR Mode 'B',and I have on computer. This turned out to be someone comes up on the calling several occasions observed the ad- very difficult, and the situation was frequency at 50 bauds, you print a vantages of AMTOR over the other really not made any easier when lot of rubbish! two modes. Under weak signal small computers initially became conditions, short extracts of the readily available, as the required Operating Procedures bulletin were recognisable in RTTY, programs could not be run in a high in110 baud practicallynothing levellanguage suchasBASIC. When operating AMTOR, the ASCII, but almost perfect copy in However, Peter Martinez, G3PLX first thing to do is to send 'CQ'. AMTOR mode 'B'. This was due in published two articlesinRadio Normal practice is to send 'CQ' in the main to the synchronous nature Communication,themonthly mode 'B' giving your selcall in the of AMTOR and to the fact that each magazine of the Radio Society of transmission. eg: CQ CQ CQ DE character, as I described above, (June/July1980) G3RDG G3RDG G3RDG. SELCALL getting GreatBritain, hastwochancesof that described a design for a code - GRDG through.Realisingthis, and ap- converter board which allowed any CQ CQ CQ DE G3RDG G3RDG preciating the increasing interest in conventional RTTY stationto G3RDG. SELCALL GRDG PSE K K the mode, W1AW recentlyan- operate on AMTOR with the addi- This message can either be sent by nounced that the RTTY bulletins tion of a few level -shifting circuits. handkeying,or,ifyouare would be immediately followed by This became available in kit form operating with a computer, it can AMTOR, and finally in ASCII if time and also as a made-up board, and be put into the memory, and sent permitted. was known as the Mk 1.I purchas- out by pressing one programmed For several years after the in- ed one of these at the BARTG rally key. When the message has been vention of TOR by Mr Van Duuren, (BritishAmateur Radio Teletype sent, the calling station reverts to the cost and complexity of the logic Group) at Harpenden in July 1981, 'Standby'. We will assume that a circuitry put this method well out of and after adding the necessary in- station answers my CQ, and calls reach of amateurs, but the coming terfaces,(levelshiftingcircuits me inmode 'A'by my selcall. of the microprocessor age made mentioned above), to my ST 6 ter- (Remember that no one else can the arranging of such a system a minal unit,I commenced operation answer toit). The other station possibility, and AMTOR first came in the new mode. I do not exag- commencesbytyping'GRDG' into existence in September 1978. gerate when I say that everything I which activates my transmitter. He Its very operation is due almost en- had read about AMTOR was true, then perhaps, sends a few words tirely to Peter Martinez, G3PLX, unbelievably so! This kit is now ob- such as 'de G3XYZ' followed by who told me one day at a BARTG solete, being superseded by the Mk ' + ?'.Thusthetransmissionis rally that it was the now familiar 2 which isavailable today from passed back to me, and the QSO is 'chirp -chirp' of TOR that first at- GPW ElectronicsofFerndown, under way. It carries on in the nor- tracted his attention to the mode Dorset. mal way, each end passing the when turning the dial on 80 meters transmission back and forth by find out one evening. He set out to Call-up Facilities means of the' + ?'combination about it, in due course discovered sent from the keyboard. However, that it was TOR and determined to One of the big attractions of the there is a most interesting extra in adapt it for amateur use. All praise AMTOR mode 'A' is the availability the mode 'A' AMTOR operation. must be given to his perseverence Either end can 'break-in' to the and foresight that, in a space of 5 of a 'SELCALL', that is, a 4 letter code which is uniquely yours. For others transmission in order to raise years, AMTOR has become an a point or answer a question on the established mode for amateurs on example, myselcallcode is 'GRDG', where my call is G3RDG. spur of the moment by pressing HF and VHF throughout the world. The selcall for GW3DZJ would be 'Control' and 'C' at the same time. 'GDZJ',andsoon.When on This action forces the transmission Amateur Use 'standby' the AMTOR system con- back to the other end, and so the tinuously monitors the incoming bit questionorwhatevercan be Initially experiments were made stream for this particular code, and answered followed by the usual intheUnitedKingdon undera only when your code is received ' + ?',passingthetransmission

HAM RADIO TODAY JULY 1984 25 back to the originator. In this man- not add to this. There are other scientificexpeditions have used neritispossible to have what manufactured unitsappearingin AMTOR units for HF communica- amounts to a really good conversa- the market place. HAL who are tion back to base, and one maritime tion - passing the transmission already well-known for their RTTY radio operator reports that he built back and forth as if one were face gear,haveintroducedtheir an AMTOR kit while at sea and pat- to face with the other. ARQ1000, which isa code con- ched it into the ship's equipment, Amateurstations in many verter unit and interfaces with their replacingthe ageing commercial countries are active using AMTOR existingterminalunit and video machine,withmuchimproved including Austria, Nigeria, Sudan, displayequipment.MICROLOG, results! Apart from the cheapness Zimbabwe, USA, Norway,Italy, another name well-known inthe of AMTOR approach, another area Malaysia,Sweden, Switzerland USA for their RTTY terminal, are in- where amateur techniques have and Japan to name but a few. In troducing an add-on facility which shown the wayistheuseof fact, there are over 25 countries should be an interesting proposi- transceivers for this mode. A com- active on this mode. There is also tion for existing operators. KAN- mentinpassing...Some of you activity on 2 meters on AMTOR, at TRONICS inthe USA isanother might wonder whether the relays in least, in the London area on a fre- name which comes to mind. They a transceiver would stand up to the quency of 144.590 MHz. The call- have just launched a range of pro- change from transmit to receive ing frequenciesfor the AMTOR gramstorun AMTOR onthe every 450 mS. Well,I can only tell mode on the HF bands are 3588 VIC20, CBM64 and Apple com- you that I have been using my TRIO KHz, 14075 KHz, 21075 KHz and puters. These represent a low-cost TS820S for the past two and a half 28075 KHz. There is one African introduction to AMTOR for those of years with more or less continuous station who, at the time of going to you already owning the computers AMTOR work, and no fault has press, maintains a standby watch in question, and they offer facilities developed in the relays yet! at weekends on 21115 KHz. equivalent to the original Mk1 kit, using separate ARQ and FEC pro- Further Reading Getting Started grams, and no RTTY or CW. Unfor- tunately the European versions of I hope that the above has given As I mentioned previously, the the VIC20 and CBM64 will not run you some idea of the working of easiest way to get on AMTOR is to these programs because ofdif- thislatest methodofkeyboard purchase the Mkt kit from GPW ferences in system timing. communication, and perhaps whet- Electronics and tieit up with your ted your appetite for more informa- existing RTTY gear, but a number Commercial Feedback tion. In which case, I would recom- of people, including yours truly, use mend reading: - thecommerciallymanufactured Although AMTOR was original- a. 'AMTOR', an improved 'AMT -1' from ICS of Arundel, West ly 'acquired' from the commercial radioteleprintersystem,using a Sussex. This unit was reviewed by world, there is some evidence that microprocessorbyPeterMar- TonyBailey,G3WPO,forthe a growing number of AMTOR units tinez,G3PLX.Radio Communica- technical aspects of the unit, and arefilteringinto commercial ap- tion August 1979 yourstruly(asa wellsatisfied plications, mainly because of the b. 'AMTOR the easy way' by Peter user!) inthismagazinein much more expensive commercial Martinez,G3PLX. RadioCom- September 1983 so really I need equipment equivalent. At least two munication June/July 1980. The ICS AMT -1is controlled entirely by the operator's home computer 'terminal unit'. A number of LEDs behind the translucent front panel insert indicate the status and mode of the AMT -1, which can also be used as an interface for CW and RTTY.

26 HAM RADIO TODAY JULY 1984 YT-5A/100N=1 with simple equipment Part 3

3. Operating news" newsletter published by when the moon is close to perigee (to When to listen K2UYH. There is a weekly net held on give the strongest signals). Since both The best way to learn about EME SaturdaysandSundayson of these phenomena have approx- operating procedures isto spend 14345kHz between 1600 and 1700 imately 27 day cycles, sked some time listening before attempting GMT (for stations interested in 70cm weekends usually occur once every to make contacts. This usually occurs and above), and 1700 onwards (for four weeks. The dates of the anyway, as one is usually only too stations interested in 2m). The 70cm 70/23cm sked weekends for the re- keen to try out the antenna and net begins with European traffic, and mainder of 1984 are: May 12/13, receiver as soon as these parts of the at 1645-1655 to 1700 there is a June 9/10 or 23/24, July 21/22, system are ready. The first question short period of international traffic, August 18/19, September 15/16, is, when to listen? Unfortunately EME with W1JR acting as net controller. October 13/14 or 20/21, November activity levels are not yet high enough EME oriented stations are also to be 1 7/ 18 and December 15/16. Activity to guarantee that someone will be on found on Oscar 10, around levels on these dates should be high whenever you want to listen. Activity 145.95MHz, or on Mode L. Both the enough to enable some signals to be heard whenever the moon is up. In the final part, Dr Charles Suckling, G3 WDG, Operating Frequencies describes EME operating procedure. On number 2cm, 23cm, most EME occurs in the bottom 30kHz of tends to be concentrated on one 20m net and Oscar 10 are useful the normal communication band. On weekend per month, referred to as the sources of information, and one can 70cm, this means 432.000 to 'sked weekend'. This does not mean often hear skeds being arranged. 432.030MHz. The "newsletter" sk- that all activity is in the form of skeds: The dates for the sked weekends ed frequencies are 432.000, indeed most activity during these are chosen so that they occur when 432.025 and 432.030MHz, and weekends is'random',ie non - the moon has a high positive (norther- these frequencies should be left clear prearranged. Skeds are arranged of ly) declination (to give the maximum during sked weekends. Most of the course, either by personal arrange- amount of operating time as well as random activity is concentrated into ment or via the "432 and above EME the best windows), and if possible the segment432.005 to 432.020MHz. 432.010MHz is the CW 'callingchannel',andthis tends to get rather busy during sk- ed weekends, and weaker stations usually find it more productive to call CQ a few kHz either side of this frequency. Operating Procedure

Because EME signals are very weak compared to signals normally found on the bands, special operating procedures have been devised to make contacts easier to achieve. With very few exceptions,strict time periods are used for skeds, CQ calls, replies to CQ calls and all subsequent traffic. On 2m two minute periods are used, and on 70cm 2.5 minute periods are used. During the early stages of a sked or QSO, the last 30 seconds of a period are reserved for reports only. The end of a period

(> HAM RADIO TODAY JULY 1984 27 is terminated with a "K" and no 95 REM MOON LOCATION PROGRAM 700 De = D7 - I 96 REM callsigns. The rest of the period is DEFINED CONSTANTS 710 IF D7 = 0 THEN GOTO 730 100 P5 = 2.0000000000 * 720 GOTO 750 used to send the callsigns, usually 3.1415926535 730 IF D8 ) = 0 THEN GOTO 1840 sent in three -by -three sequences. 110 D5 = 360.000000000 / P5 740 B = El The RST reporting system is only 120 R5 = P5 / 360.00000000 745 REM CALCULATION OF LUNAR used when signals are good. Normally 130 DEF FN A(X) = INT (X * D5 * LAT AND LONG 10 + .5) / 10 750 T = (8 - INT (B / 100) * 100) 140 DEF a different system is used, called the FN B(X) = (X - INT (X)) * 1440 + INT (B /100)/ 24 "TMO" system. In this, the letters T, * P5 760 T5 = T1 + T 145 REM DATA INPUT SECTION 770 t*1 = FN B(.751213 M, or 0 are used as the report. They 150 INPUT "LATITUDEDEG.MIN^ .036601102 * T5) have the following meanings: ":1_5,U5 780 K2 = FN 8(.822513 T: very weak, barely perceptible 160 INPUT "LONGITUDE DEG.MIN? .03629116457 * 1-5) ";L6,U6 790 K3 = FN 8(.995766 signals which are not strong enough 170 LA = L5 + INT ((U5 / 60) * .00273777825 * T5) to allow callsigns to be identified; 100) / 100 800 K4 =FN 8(.974271 180 LO = L6 + INT ((U6 / 60) * .0338631922 * T5) M: weak signals, but strong enough 100)/ 100 810 K5 =FN B(.0312525 190 L5 = (L5 + U5 / 60) * R5 .0367481957 * T5) to allow callsigns to be positively iden- 200 L6 = (L6 + U6 / 60) * R5 tified; 820 L8 = K1 + .658 * R5 *SIN (2 210 INPUT "INCREMENT IN MINUTES? * K4) + 6.289 * R5 * SIN (K2) ":1 0: good signals, strong enough to 830 Le = L8 - 1.274 * R5 * SIN 220 U5 = INT ((U5 / 60) * 100) / allow callsigns to be copied "in 100 (K2 - 2 * K4) - .186 * R5 * SIN (K3) blocks" without too much difficulty. 230 U6 = INT ((U6 / 60) * 100) / 100 840 L8 = L8 + .214 * R5 *SIN (2 On 70cm, M or 0 reports are good 240 I6 = 100 * K2) - .114 * R5 * SIN (2 * K5) enough for the QSO to be valid, while 250 GOTO 260 850 LB = Le - .059 * R5 *SIN (2 260 * K2 - 2 * 1'4)- .057 * R5 * SIN on 2m the minimum is an 0 report. Of INPUT "DAY,MONTH.YEAR.TIME (K2 + K3 - 2 * K4) START.TIME FINISH- ":1:),M,Y.B.E1 860 1(6 = K5 + .6593 * R5 * SIN (2 course, reports have to be acknow- 270 Y1 = Y - ( INT (Y / 100) * ledged by the other station for the 100) * r4) + 6.2303 * R5 * SIN (F2) 280PRINT 1.272 * R5 * SIN (K2 - 2 * t4) QSO to be complete, and on EME this 290 PRINT 870 L7 = 5.144 * R5 * SIN (K6) is done by suffixing an R to the report 300 NS$ = "N" .146 * R5 *SIN (r5 - 2 * K4) 310 IF LA < 0 THEN NS$ 875 REM CALCULATION OFLUNAR RA AND DEC being sent or by sending R on its own, 320 EW$ = "W" 330 880 DI = COS (L7) * SIN (L8) * as appropriate. M or 0 reports on IF LO < 0 THEN EW$ = "E" .397821 + 340 PRINT "MOON SIN (L7) .917436 70cm, or an 0 report on 2m, should 890 D1 = ATN (D1 / SQR (1- D1 ":13;"/";M:"/";Y1;" FROMLAT= ";LA 2))) only be sent when both callsigns have * SON (LA);NS$;" LONG=";LO * SON (LO);EW$ 900 G1 =50 + .5 + ((D1) / (.792)) been positively identified. This is dif- * D5 350 Fl = 0 ferent to meteor -scatter procedure, 360 910 G2 =80 + ((D1) / (.808)) * D5 PRINT 920 G3 = 370 Ii = 2 141.5 -((Di) * (.738) * for example, where reports are sent D5) 375 REM CALCULATION OF JULIAN before callsigns have been copied. DATE 930 G4 =170.5 -((Di) * (.857) * D5) 380 IF M = 3 THEN 460 940 A2 = ( 390 IF COS (L7) *COS (L8)) INT ((Y - 1853)/ 4) < 11 COS (D1) Worked Example THEN GOTO 420 950 Al = ( COS (L7) *SIN (L8) * 400 CI = - 1 410 .917436 - SIN (L7) * .397821) / This procedure may seem a little GOTO 430 COS (D1) 420 Cl = 0 960 A = complicated, and indeed some begin- 430 J1 = 365 * (Y - 1853) + D + 30 ATN (Al/ A2) * (M + 9) + 970 GOSUB 1230 ners do get confused! I hope that a INT ((M + 10)/ 2) 980 R1 = A 440 J2 = short example will help to make things INT ((Y - 1853) / 4)+ 1 990 Ll = .065709822 * T1 + Cl 1000 L = T * 24 * 1.002738 + clearer. Suppose that two stations, 450 GOTO 570 6.646055 + (LI - INT (L1/ 24) * W1JR and K2UYH have a sked on 460 IF INT ((e - 1852)/ 4) < 11 24) THEN GOTO 490 1010L =(L - INT (L / 24) * 24) 70cm, with W1JR taking the first 470 Cl = 1 - 1015 REM CALCULATION OF GHA transmit period. If all goes according 480 GOTO 500 FROMLOCAL SIDERIAL TIME 490 Cl = 0 1020G = (L / 24) * P5 - R1 to the book, the QSO would proceed 500 IF M = 9 THEN 540 1030 IF G < P5 THENGOTO 1060 as follows: 510 IF M = 11 THEN 540 1040G = G - P5 1st period: W1JR sends K2UYH 520 C2 = 0 1050 GOTO 1090 530 K2UYH K2UYH DE W1JR W1JR GOTO 550 1060 IF G < 0 THENGOTO 1080 540 C2 = 1 1070 GOTO 1090 W1JR repeated for 2.5 minutes. 550 J1 = 365 *(Y - 1852) + D + 30 1080G = G + P5 2nd period: K2UYH sends W1JR * (M - 3)+ INT ((M - 2)/ 2) 1085 REM CALCULATION OF LHA 560 J2 = INT ((Y - 1852)/ 4)+ FROMGHA W1JR W1JR DE K2UYH K2UYH Cl + C2 1090H = L6 - G K2UYH, repeated for two minutes, 570 J = J1 + J2 1095 REM CALCULATION OF 580 T1 = J - 17472.5 ELEVATION then M M M M M repeated for 30 585 REM CALCULATION OF DAYS 1100 E3 = COS (L5) * COS (H)* seconds (his report to W1JR). SINCE LAST PERIGEE AND AGE OF MOON COS (D1) + SIN (D1)* SIN (L5) 590 T9 = J + 2397547.5 1110 E2 = SQR (1 - (E3 * E3)) 3rd period:W1 JR sends K2UYH 600 T9 = T9 - 2444507.6 1115 REM PARALLAX CORRECTION K2UYH K2UYH DE W1JR W1JR 610 17 = T9 - 14.6 FOR ELEVATION 620 T8 = INT (T7 / 29.5306) W1JR repeated for 2 minutes then OR 1120 E = ATN ((E3 / E2) -(1 / 630 Te = T7 - TB * 29.5306 (61.33 * E2))) OR OR OR OR repeated for 30 640 Q = INT (T9 / 27.5545) 1130 F = ATN (E3 / E2) seconds (his report to K2UYH, plus 650 R = T9 - (27.5545 * 0) 1135 REM JUMP TO TIME 660 S = 24 * R INCREMENTING ROUTINE IF MOON IS acknowledgement that he has copied 665 REM START OF MAIN BELOW HORIZON his own report). CALCULATION LOOP 1140 IF E < 0 THENGOTO 1770 670 D9 =(B - INT (B / 100) 4th period: K2UYH sends W1JR 1150 IF E ; 16 * R5 THEN GOTO 100) + INT (B / 100) * 60 1770 W1JR W1JR DE K2UYH K2UYH 680 D6 = (El - INT (El/ 100) 1155 REM CALCULATION OF K2UYH repeated for 2 minutes then R 100) + INT (El/ 100) * 60 AZIMUTH 690 D7 = D9 - D6 1160 A2 = R RR Rrepeated for 30 seconds SIN (DI) ( COS (L5) *

28 HAM RADIO TODAY JULY 1984 COS (F)) 1550 Z3 = FN A(G) One final point about procedure.

1170 A2 = A2 - ( SIN (L5) / COS 1560 Z4 = FN A(D1) Quite often stations do not stick to the / 1570 IF Fl = 1 THEN GOTO 1650 (L5)) * ( SIN (F) COS (F)) 2 minutes of callsigns and 30 1180 Al = SIN (L5)* SIN (D1) + 1580 RI = INT (R) COS (L5)* COS (D1) * COS (H) 1590 PRINT "DAYS SINCE PERIGEE= seconds of reports once they have / "0:21 1190 Al = ( SIN (H)* COS (D1)) copied a report from their QSO part- SOR (1 - AI 2) 1600 PRINT "AGE OF MOON= ";INT 1200 A = ATN (Al/ A2) (T8 * 10)/ 10;" DAYS" ner. Instead, they increase the time 1210 GOSUB 1230 1610 PRINT spent sending reports, since by that 1220 GOTO 1370 1620 PRINT " GMT AZ EL time they know that the other station 1225 REM SUBROUTINE TO REMOVE GHA DEC DOP" AMBIGUITIES ASSOCIATED WITH ATN 1630 PRINT has already copied the callsigns. Do FUNCTION not be surprised if this happens to 1230 IF A = 0 THEN GOTO 1250 1640 Fl = 1 1240 GOTO 1280 1645 REM PRINTING OF FINAL you, but I would recommend that you 1250 IF A2 <0 THEN GOTO 1270 RESULTS (S$=LEADING ZEROS, STR$ stick to the formal procedure until you 1260 GOTO 1360 CONVERTS TIME TO A STRING, are fully familiar with EME procedure. 1270 GOTO 1360 Z1=AZIMUTH, Z2=ELEVATION, Z3=GHA, 1280 IF A> 0 THENGOTO 1340 Z4=DECLINATION, F=DOPPLER SHIFT) When you hear your first EME 1290 IF A2 <0 THEN GOTO 1320 1650 PRINT S$; STR$ ( INT (B + signals, do not be too surprised if you 1300 A = P5 + A .5)); 1310 GOTO 1360 1660 HTAB 7 find them rather difficult to copy. 1320 A = P5 +(A - P5 /2) 1670 PRINT Z1; Apart from the fact that the signals 1330 GOTO 1360 1680 HTAB 14 1340 IF A2 = > 0 THENGOTO 1360 1690 PRINT Z2; are weak, they are also subject to 1350 A = A + P5 / 2 1700 HTAB 20 rapid fading (libration fading). The net 1360 RETURN 1710 PRINT Z3; result is thatyou onlyheara certain per- 1365 REM CALCULATION OF 1720 HTAB 27 DOPPLER SHIFT FOR ECHOES ON 432MHZ 1730 PRINT Z4; centage of what is being sent, almost HTAB 34 1370 D7 = - .38 * ( SIN (.526 * S 1740 on a character by character basis. / 57.3)) 1750 PRINT F 1380 F = 432 * (D7 - (7.1 * COS 1760 Il = T With experience, the fading seems to

(D1)* COS (L5) * SIN ( - 1 * 1765 REM TIME INCREMENTING become less of a problem. In a sked, H))) ROUTINE you know in advance what the call - 1390 F = INT (F) 1770 HR = INT (B /100) 1400 IF (T - Il) (2 * I) / 1440 1780 MN = B - 100 * HR signs will be. When listening to the THEN GOTO 1420 1790 MN = MN + I signals, try to pick out parts of the 1410 GOTO 1430 1800 B = 100 * (HR + INT (MN / 1420 PRINT 60)) morse characters. This helps the brain 1430 IF INT (B + .5) 9 THEN 1810 MN = MN - ( INT (MN / 60)) * to 'lock -in' to the sending speed. GOTO 1460 60 Sooner or later a complete letter will 1435 REM ROUTINE FOR PUTTING 1820 B = B + MN LEADING ZEROS IN FRONT OF TIME 1825 REM LOOP BACK TO MAIN be heard. The brain can then an- (B=TIME) CALCULATIONS ticipate what the next letter ought to 1440 S$ = "000" 1830GOTO 670 1450 GOTO 1530 1840 PRINT be, and if part of it only is heard, you 1460 IF INT (B + .5)> 99 THEN 1850 PRINT "RE -RUN PROGRAM? (YIN can still correlate it with what was GOTO 1490 sent. Of course, it is more difficult to 1470 S$ = "00" 1860 INPUT D$ 1480 GOTO 1530 1870 IF D$ = "Y" THEN GOTO 100 identify callsigns when you have no 1490 IF INT (B + .5) 999 THEN 1880 END idea beforehand who you are listening GOTO 1520 1500 S$ = "0" to, but with experience you build up a 1510 GOTO 1530 'data base' of callsigns which you can 1520 S$ = "" try to fit to what you hear, until you 1530 Zl = FN A(A) BASIC program for determining the 1540 Z2 = FN A(E) position of the moon. get a positive identification. Taping signals is good idea, as one can go back to the tape afterwards and (acknowledging that he has copied 30 second reporting period. Some possibly copy more then than you did his report). stations do not do this, however, but at the time. At this point, the QSO is com- continue sending callsigns for a full plete, and pleasantries such as TNX, 2.5 minutes. The advantage of not 73, GL etc are usually sent with no sending anything is that it is a positive Moon Tracking special procedure, except for time signal to the QSO partner that you are periods. Of course, things do not hearing nothing. Callsigns sent during Finally, we come on to one very always work out as well as this, for a reporting period could be confused important aspect of EME operating - example a station may not copy the for reports. keeping the antenna pointed at the report, and repeats are then When answering CQ calls, the moon. If you have followed the sug- necessary. The lack of an R from the same procedure should be followed gestions above, you should now have other station will tell you that you as for skeds. You have the option of an antenna with calibrated elevation have to send the report again. If you sending callsigns and a report, or just and azimuth readouts. All you need to can hear your QSO partner, but not callsigns, in your reply. The advan- know is the elevation and azimuth of well enough to get both callsigns then tage of sending callsigns and a report the moon at the time and you are in use the T report, as it tells the other is that the contact can be completed business. If your antenna is not equip- station that you are at least getting more quickly - which might be desir- ped with calibrated readouts, then something.Itis possible that as a able in a contest, but in EME working you have only yourself to blame when result of this your partner might reduces the other stations "callsign you have to miss that sked because it change the polarisation of theantenna deciphering" time by 20%. If the was cloudy and you could not see the and could be stronger on the next other station replies with QRZ?, then moon! transmission. If you hear nothing at all you should reply with callsigns only, There are a number of ways of from the other station, the strict pro- as the other station is obviously not working out the moon's position, but cedure is to send nothing during the copying you very well. by far the most convenient is to use a

HAM RADIO TODAY JULY 1984 29 computer. The program reproduced here was written for an Apple II + (as were all the programs in this series), but should run with little or no modi- fication on most machines. It is based on an original program by WA1JXN, and I have added three useful features. In addition to printing out theelevation,azimuth and astronomical co-ordinates of the moon, the program also gives the number of days since perigee for the day in question, the age of the moon (the number of days since New moon) and the total Doppler shift (in Hertz) which you will find on your own echoes (on 70cm). The program can be easily modified to give the Doppler shift for other frequencies by chang- ing the 432 in line 1380 to the fre- quency required. The one-way Dop- pler shift is half the number printed out, and by adding together the one- way Doppler shifts for your site and for your QSO partner's, the overall The 4 x 16 ele yagis of 12 MBC provide an excellent signal Doppler shift can be calculated. The on 2 m EME number of days since perigee is useful 1200 202.2 54.1 15.1 17.7 -36 1300 223.549.229.6 17.9 -224 RSGB has been asked to process all to know, as it allows you to estimate 1400 240.842.244.2 18.1 -387 applications for these permits prior to 1500255.1 33.958.7 18.2 -516 the current EME path loss. Remember 1600 267.4 25 73.2 18.4 -603 their submission to the FTI. It should that there is a 2dB change in path loss 1700 278.7 16.1 87.7 18.6 -642 1800 289.7 7.4 102.2 18.7 -630 be noted that the Special Research as the moon goes from perigee to Permits allow the use of high power apogee. It takes about 27 days for the As with the sun program, you must only for the purpose for which they moon to go from one perigee to the enter the latitude and longitude as are issued, in this case EME. next. The age of the moon is given, negative numbers if your location is mainly so that you can be aware if the south the equator, or east of Green- moon is close to New moon. At this wich, respectively. Further Information point in the moon's orbit, it can hap- To track the moon, all you have to In this short series on EME opera- pen that the sun and moon are close dois to set the antenna to the tion,I have tried to cover all of the together in the sky, and your antenna predicted co-ordinates at suitable necessary background needed to could pick up some noise from the time intervals. How often this has to become active on EME. Best of luck! sun, which would degrade the be done depends on the beamwidth of For further information, the following receiver's performance. the antenna. The narrower the beam - publications are recommended: Suppose that you want to run the width, the more often you have to up- 1. "432 and above EME News". This program for 29 May, from 0000 to date the position of the antenna. A 4 is a monthly newsletter intended for 2400GMT, at intervals of 60 yagi array on 432MHz ought to be up- active EME stations needing sked in- minutes, from a site with a latitude of dated at not greater than 10 minute formation.Itis published by Allen 51deg 30min North, and a longitude intervals. Katz, K2UYH, RD *4, Old Trenton of 1 deg 50min West. The program's Road, Trenton, NJ 08691, USA. In prompts and appropriate entries are Special Research Permits order to receive the newsletter, SAEs as follows: should be sent to K2UYH, together LATITUDE DEG,MIN? 51,30 Since power levels in excess of with $1 per envelope. LONGITUDE DEG,MIN? 1,50 the UK legal limit are almost always INCREMENT IN MINUTES? 60 2. "The EIMAC EME Notes". These DAY,MONTH,YEAR,TIME START,TIME FINISH? required for EME working, it is unfor- contain a lot of very useful informa- 29,5,1984,0000,2400 tunately rarely possible to operate on tion about EME and are available free EME within the terms of the normal The program then outputs the follow- UK licence. A limited number of of charge from Bob Sutherland, ing: W6P0, c/o Eimac Division of Varian, "Special Research Permits", which in 301Industrial Way, San Carlos, some cases allow operation at higher MOON 29/5/84 FROM LAT= 51.5N LONG= 1.83W California, USA. power levels, may be available to DAYS SINCE PERIGEE= 19 licenced 3. RSGB VHF/UHF Manual, by G.R. AGE OF MOON= 27.9 DAYS amateurs who can Jessop G6JP, pp. 10.16-10.20. GMT AZ demonstrate a need for one. These EL GHA DEC DOP are issued by the DTI as an exten- 040069.9 4 259 16.3 926 Acknowledgements 050080.8 12.9 273.5 16.5 946 sion to the normal licence, and en- 060091.9 22.1 288 16.6 913 quiries should be addressed to the 0700 103.831.3 302.5 16.8 833 I would like to thank G4FRE, 0800 117.439.9 317.1 17 708 RSGB, c/o the Chairman of the G3SEK, and G3LTF for providing 0900 133.847.5 331.6 17.2 548 Licensing 1000 154.1 53.1 346.1 17.4 362 Advisory Committee some of the information used in this 1100 177.955.5 .6 17.5 f63 (DavidPratt,G3KEP).The series.

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Free delivery. 11.501343TR-8400 70cm Transceiver 279 Price1302KB-1 De luxe VFO knob 52.50 Cat 500Hz CW filter 1368PS-10 DC PSU No Type Description £ 1354YK-88C SP-40Compact Mobile Speaker 15.75 10991315YK-88CN 270Hz CW filter 361369 1331 TS -9030S Transceiver, HF, W. gen. cov. receiver 1371 MC -46 Auto -patch Up/Down microphone 42.50 1330TS-930S +ATUAs above, with automatic ATU 11991352YK-88SN 1.8kHz SSB filter 50 Receiver 2591313MC-60A Desk Top Microphone, built-in pre -amp. 1329SP-930 Speaker and filters 571328R-600 2m All Mode Transceiver, 25W 419 541333 DCK-1 DC Operation Cable Kit 8.261339TR-9130 1313MC-60A Desk Top Microphone, scanning 1372 BP -9A System Base 321332R-1000 Receiver 299 1357YK-88A1 6kHz AM filter 331373SP-120 External Speaker 500Hz CW filter 321318SP-100 External Speaker 114 1356YK-88C1 DC Operation Cable Kit 8.261374PS-30 DC Power Supply 1348YG-455C-1 500Hz CW filter 751333DCK-1 AC Adaptor for memory back-up 6.43 751335R-2000 Receiver 3991370 BC -1 1349YG-455CN-1 270Hz CW filter 1371 MC -46 Touch-tone microphone 41.50 Transceiver, HF, w. gen. coy. receiver 7191355YG-455C 500Hz CW filter 52 13247S -430S Transceiver, 1.5W FM, 10CH Mem. 1951313MC-60A Deluxe Desk Top Mic. + pre -amp. 1310PS-430S DC power supply, de luxe cooled 1131337TR-2400 Compact Mobile Speaker 1301 ST -1 Base Stand 451369SP-40 1319SP-430 External speaker 30.50 1341 TR-9500 70cm All Mode Transceiver 429 33.751309MC-30S Hand Microphone 14 1334FM-430 FM Unit 2191372 BO -9/9A System Base 48.50 Mobile Mount 12.501338TR-2500 2m FM Transceiver 34 1321 MB -430 Base Stand 521373SP-120 External Speaker 1322AT-250 Automatic ATU 2801304ST-2 DC Power Supply 59 541360MS-1 Mobile Stand 321307PS-20 1313MC-60A Desk Top Microphone 75 1370BC-1 AC Adaptor for memory back-up 8 Antenna Tuning Unit 1342VB-2530 25W Amplifier 50 1320AT-130 Speaker microphone 171313MC-60A De luxe Desk Top Mic + pre -amp 1354YK-880 500Hz CW filter 1306SMC-25 Compact Mobile Speaker 15.75 361361 BT -1 Manganese Battery Case 6.501369SP-40 13157K-88CN 250Hz CW filter 261316TL-922 2KW HF Linear Amplifier 799 1.8kHz SSB filter 1311 PB-25 Nicad Battery 1.8-150MHz Station Monitor 250 1352YK-88SN 1305SC-4 Soft case 141376SM-220 1353YK-88A 6kHz AM filter 1351 HC -10 Digital World Clock 65 1362 LH-2 De luxe leather case 50 1314PS-30 DC PSU Variable Tone Encoder 1350PC-1A Phone Patch Transceiver, HF 60913637U -35A Antenna 8 132675-530S 4513647U -35B Programmable Tone Encoder 1303RA-1 1327SP-230 External Speaker 1379MC-42S Spare - Up/Down Microphone 16 Antenna Tuning Unit 1491365DG25 DC Adaptor for 12VDC 1325AT-230 Rubber Antenna Desk Top Microphone 541366RA-4 Prices include VAT and Carriage. 1313MC-60A 1367 RA -3 Telescoping Antenna 1312 MC -50 Desk Top Microphone 32 Penetrate the four corners of the earth with the Western DX "PENETRATOR35 WESTERN ANTENNAS(Carriage paid) IN USE FROM VK7 to VE7! 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HAM RADIO TODAY JULY 1984 31 Mplco) Yesterday We could hardly believe our ears, used to operating "Mule Mobile" standing on the ground and the but the order was quite clear. The - both phone and CW, whilst base of the antenna is clearly visi- Section had toprovide wireless walking alongside the mule on the ble. communication for a Company of move.Nobodyhadevencon- Another photograph (B) shows Infantry who had been detailed to sidered using elephants, and few this type of set mounted on a mule, maintainorderduring a Hindu had been nearer to those large the pannier on the opposite side religious festival at Horwar, on the animals than a visit to the zoo or carried the batteries to operate the banks of the River Ganges, and the viewing them in procession in one equipment. The high tensionof radio equipment would be carried of the Indian Princely States, and 150 volts was made up from 100 1.5 volt inert cells and two volt ac- cumulators were used to heat the Have you ever operated a 'Mule Packet'? Or been valvefilaments.Theclose-up mobile on an Elephant? Well, George Metcalfe, photograph of the WirelessSet No.1on the ground provides a G6VS, has... good indication of the size of the equipment; towards the right hand there was no opportunity for a trial side, just underneath the second runtosee how the equipment control knob is an attachment for could be fitted and carried on the housing a gents pocket type watch, elephants. The only solution was to thecompartmenton theright take all the harness used for mule housestheheadphones,micro- transport and adapt it as best we phone and morse key,and the could when we had an "Eyeball" small drawer above that compart- with the elephants. ment contains spare valves By present day standards, the Mounting the equipment on the military radio equipment we used in elephantspresentedmanypro- the mid 1930's would be con- blems, as, even with the animal ly- sidered very primitive. The Wireless ing or kneeling down, its back was Set No.1 was housed in a case ap- a good six or seven foot above proximately 14 inches high, 22 in- ground, and when the elephants ches wide and about 8 inches 'saddles'hadbeendesigned deep, and the transmitter consisted wireless sets had not even been in- of an RF pentode with anode and vented. The 'saddles' were design- screen pins at one end and grid and ed to carry the mahout (driver) and filament connectingpinsatthe two passengers with little room to other end, mounted horizontally, as spare. Eventually it was decided to a Colpitts Master Oscillator driving fit the radio equipment in the space a PM 1 LF power amplifier giving normallyoccupied bythe about 2.0 W - truly a QRP rig. The passengersandtheoperators frequency range was approximate- would ride with their legs dangling ly 4.0 to 7.0 MHz. The receiving over the side of the elephant. side consisted of the same type of Not a very comfortable position RF pentode, followed by detector but it was the only way to over- and two low frequency stages us- come the problem - needless to ing the same PM 1 LF type of valves say the operators comments were with resistance capacity coupling. hardly printable! The antenna was a vertical rod ap- The festival lasted a week, six Mobile on ELEPHANTS! proximatelyeightfeetlong 'Elephant Mobiles' were used and The WirelessSetNo.1had mounted on aninsulatedbase theirslow steady pacedidnot been carried on mules for some which was fitted to the top of the damage the radio equipment but time and the operators were well case. Photograph A shows this set played havoc with the operators

32 HAM RADIO TODAY JULY 1984 stomaches! However by the end of the week most of them overcame the'elephantsea -sickness'and operating procedure improved con- siderably. As far as the writer is aware, this was a unique experience and possibly the only time, certainly the only time before the war, that radio equipment has been carried and operated from elephants on the move. Photo D shows a 'holy man' sitting on a bed of nails - the nails were very sharp - that was taken at the same festival. The final pic- ture (E) shows a base wireless sta- tion on the North West Frontier, the petrol generator and operator are in the foreground and W/T Set 'A' with its bright emitter valves can be seen in the background.

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HAM RADIO TODAY JULY 1984 35 'fftco'ffEE JP) agood rig for the Common Man

I have reviewed many transceivers former, the subject of this review, treindented),notchfilter(with in the last year, almost all of them includes a 'turntable' notch filter. in/out button), AF and RF receiver having transistorised PA stages, The rig can only operate as it gain(concentricallymounted), and this new version of the Trio stands on AC, and is therefore only drive (requires peaking on Rx and 530 is, therefore, unusual by to - intended for home station use. The Tx), plate tuning (with pointer to give approximate frequency posi- The Trio TS530SP offers the potent combination of tionof control), output transmit loading, and a rotary for RIT/XIT. modern RF semiconductor technology, without Miniaturerotarycontrolsadjust extraneous 'bells and whistles', with rugged valve PAs VOX delay, VOX gain,noise - and at a reasonableprice. Eminently practical blanker level, and RF carrier Tx level.Push buttons select noise thought HRT, and so did Angus McKenzie, G3OSS, blankeron/off, VOX on/off, Tx as this review reveals. MOX, 20 dB RF attenuator on Rx processor in/out and IF narrow/nor- day's standards as it incorporates main tuning VFO rotates at a rate of mal (optionalfilters available for both valves for the driver and PA 25kHz per revolution, and comes narrow CW and SSB). 500Hz and output stages, the PA including up against end stops, giving around. 270Hz CW and 1.8kHz SSB filters two 6146B valves operatingat 75kHz overlap at each end of the are available to special order, with around 900V HT. The transceiver selectable bands, a band change installation details given in the in- covers all amateur bands from 1.8 switch allowing for the three new struction book. Further push but- to 29.5MHz in 500KHz chunks. ones, and, on 10m, 28.5 to 29.0, tons select XIT, RIT and crystal There is only one intermediate fre- and 29.5 to 30MHz being accom- marker at 25kHz intervals.This quency whichisat8.83MHz, modated by pushing in a 500kHz marker is much more convenient whereas the TS830 has two IFs, 'up' button. The mode switch has than that on the 830 - which is, thus enabling variable selectivity just four positions; tune, CW, USB somewhat unusually, engaged by which is omitted from the 530. The and LSB, AM and FM being omit- turning the mic gain off. Two rotary significant difference between the ted. Rotary controls on the front switches are provided for metering 530SP and the 530S is that the panel include mic gain, IF shift (cen- (ALC, plate current, relative output / '%Vy,A-42, .4PW? //,WV/// /14., /4/ ////',4////*/./4% / Awr#,

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36 HAM RADIO TODAY JULY 1984 power and HT supply voltage) and AGC off/fast/slow. Frequencyisindicated by a flourescent type display reading in 100Hz increments which very easy to read with a blue on black colour- ing. The frequency display section also has lights for indicating notch filter,internal/external VFO, pro- cessor and RX attenuator in use. The meterisrathersmall, and therefore not easy to read ata glance. The front panel includes a % inch jack for headphones and a four pin microphone socket to the usual Trio standard, (which is not compatible with Icom or Yaesu microphoneconnections.The mainson/offswitchiscom- plemented by a 'heaters off' switch for the PA and driver valve heaters. A de -luxe tuning knob is available as an accessory, with a finger hole init for ease of use which is ball bearing mounted, the normal knob having at least an acceptable finger hole, which didn't cause too much frictionandissomewhat larger than the usual tuning mechanism finger hole.

Designed For Operability?

On the back panel is a smooth and quiet fan for keeping the PA valves cool, which runs all the time. From the top. . . The antenna socket is an S0239, and underneath it is a shrouded DC available from the TS830. There available on the TS830S. biasing screw driver pre-set for ad- are several conveniently pre -drilled The rigis completely encased justing the PA standing current. holes for fitting extra sockets on in metal and has a resonably good Another pre-set adjusts the relative the back of the TS530SP. but fairly small speaker in the top output power reading. A large wing I am delighted to report that the casing which throws sound up- nut is available to secure a separate driveavailableforfeeding wards. A carrying handle is fitted to earth (although the captive mains transverters is subject to ALC when the right side cheek whilst feet are lead is three core) and a fuse is fit- the screen grids are switched to provided both on the left side cheek ted by its side. The mains voltage earth as the PA valves remain con- and on the lower casing. The latter input can be set to either 220 or ductive. This is extremely useful as are quite large, and the front ones 240V AC. As with the TS830, the majority of rigs omit ALC on the can have extensions on them to there is a switch which can ground transverterdrive -with raise up the front half of the rig. the PA screen grids, thus leaving sometimes dire results. The TS530SP is quite handsome the valves in a conducting mode A normal % inch CW key jack is and is finished in two-tone grey. between grid and cathode, if the proyided, and by its side is an 'anti - heaters are on. As supplied, no vox' pre-set control. A 3.5mm jack On The Air transverter Tx drive output is fitted, can be used to feed an external

but there are two pins on the driver speaker. Two multi -pin DIN sockets I usedthisrigover two valveboardwhichwillgive a provide interfacing for an external weekends and have found it very suitable outputifrequired,and VFO (various options are available), pleasant to use. On receive the Lowe Electronics recommend that and a remote control socket incor- TS530S appeared to be very sen- you fit an appropriate socket on the porating pins for AF output into 8 sitive indeed, even on 10m, whilst back of the rig for this, and inter- ohms and interconnections for ex- the front end intermodulation per- connect the board and socket with ternal relays (shorting across to a formance seemed quite good. I did coax.Thiswouldthenallow pin on either Tx or Rx), PTT, and not note any problems at LF provid- TS530SP to give a few tens-of- ALC input. There is no provision for ed I sensibly used the 20dB RF at- milliwattsdrive.Similartothat antenna Rx 'breakpoints' etc, as is tenuator.Signals seemed tobe

HAM RADIO TODAY JULY 1984 37 The mechanical construction of the TS530S is rather more rugged than manyof thecurrent HF transceivers on the market. very clean, and the IF pass band volume available on the internal would obviously work admirably quite reasonable for both SSB and speaker.I liked the feel of the VFO, with the Trio 922 model for which CW. The notch filter worked par- and it is rather pleasant to get away theinterfacing isparticularly ticularly well and was, of course, from a synthesisedonefor a suitable. Finally, the rig was very useful in removing annoying car- change. This may well influence free from received spurii. riers, particularly on 80m. I already prospective purchasers since there own a TS830, and found the handl- are many folk who do not like syn- In the Lab ing very similar indeed, PA tuning thesiser 'steps'. The noise blanker and loading being simple, whilst seemed reasonable, and the VOX The input sensitivity was quite drive tuning always seemed to be circuits worked well. The IF shift the best that I have checked out on right on Tx when I peaked the con- control operated well and gave a any HF transceiver in the last year. trol up on Rx, where the control good rangeof adjustment. The The TS530SP will thus winkle out doubles as a preselector. transmitted quality was considered remarkable weak DX on 1 Om when The AGC characteristics seem- "better than average", and the the band is almost closed, showing ed reasonable, but perhaps long transmissions were very narrow. the benefits to be gained from good AGC was a little fast. Very strong There are not too many bells and sensitivity.Itwas phenomenally signals did seem to interfere very whistles' on therig,and many sensitive at LF, although this is real- slightly with extremely weak ones operatorswillundoubtedly app- ly not necessary (see my article on on 80m, showing that the filter preciate this;therigiseasy to receivers in April '84 HRT). All the wasnotrejectingtoowell master and straightforward in use. measurements were takenafter waydown it'spass band. Audio Itis also very simple to interface carefully peaking the preselector. quality is very good with plenty of the TS530SP with a linear, and it The mixer performance was

-100dBm -70dBm -100dBm -115dBm -85dBm -100dBrn -70dBm -100dBm -115dBrn -85dBm

2 rn

O O

I I I Issss SI SI I SSssSsSSSSSSSSSS S S S sSS SSSS SS SS S TIME (EACH DIVISION = 1 SECOND) TIME (EACH DIVISION =1 SECOND) TS530SP 'slow' AGC recovery time at differing `Fast' AGC recovery time at differing signal signal levels levels

38 HAM RADIO TODAY JULY 1984 good, with the RF intercept point beingquiteacceptable although not in the very top league. To put mattersintoperspective,this parameterisfarbetter than on most older transceivers, let alone many receivers. However, somewhatsurprisingly,the reciprocalmixingperformance, whilstnotbeingpoor,was nowhere near as good as it could have been, especially as it was not synthesised, and Trio need to in- crease the signal-to-noise ratio of their local oscillator feed to improve matters here. The IF selectivity on SSB was beautifully shaped down to - 60dB but (the response) open- ed out badly below this level. The CW selectivity was not quite so sharp, but reasonably well optimis- ed in practice, although again the filter response opened out badly below - 60dB. Useful 'S' Meter

The S meterproduced a reasonable reading of S9 for 40uV, gave 34dB difference between S1 andS9andgaveusefuland reasonably logarithmic readings up to full scale deflection. The product detector worked extremely well, giving surprisingly low distortion, which obviously contributed to the clean received audio. Output power was adequate into an external 8 ohm speaker, and appreciably more . . . to the bottom power was available into 4 ohms. The receiver frequency calibration within a speech pass band without specificationfor transmitter har- was accuratetowithin10Hz, affectingintelligibilitytoo much. monic rejection states that none which is superb.I was pleased to The RIT control had a range of ap- should be higher than - 40dB. The see that when you switched from proximately + / - 2.6kHz which is a worst measurement was 5dB bet- upper to lower sideband, neither littlelimitedforsomespecial ter than spec, and this was almost the indicated frequency nor the car- needs. always the second harmonic (this rier reinsertion frequency changed, was common across the spectrum Very Low Harmonics which is ideal in my opinion. The of the bands). I don't think that position of the filter on CW coin- anybodycouldpossiblymoan cides with USB, and, when swit- The transmitter gave between about the harmonic performance, ching from LSB to USB and vice - a maximum of 100 to 112W out- 21MHz being particularly good. We versa, I was pleased to see that put on CW, whilst SSB PEPs were checked the residualcarrier and there was almost no change in the around 120W across the bands. noise output referred to the peak relative position of the pass band We had a good look at the inter - sideband output level, and rejection referred to the carrier,with the modulation products at both 1 00W was excellent. Alternative sideband variable band pass IF shiftinits and 25W PEP output resulting from rejection was amazingly good at centre 'indent' position. The AGC two -tones in the audio pass band. - 63dB. The transmit frequency pen charts show 'fast' AGC to be You can see from the photographs accuracy on CW was within 20Hz very fast indeed, whilst 'slow' is that high order products fell back which is stunningly good. slightly faster than average, but very rapidly, which obviously con- The transmittedfrequency having a slowerrecoveryon tributed to the good transmitted response, checked from the mic weaker signals. The notchfilter audio reports. They clearly vanish- socket input to RF carrier out, was measured extremely well, and far ed more quickly than I have usually very flat from 400Hz to 2kHz and better than those on most of the noted on transistorised PA stages, 3dB down at 2.3kHz, falling very competition. The notch was quite and itis for this reason that many steeply above 2.7kHz. I consider sharp, so the filter can be used operators prefer valve PAs. The the response just about ideal for

HAM RADIO TODAY JULY 1984 39 good intelligibility whilst preserving Trio TS530SP SSB Received Response a narrow pass band. We checked the receive response from the out- put of the product detector to the external speaker socket, and it was onlymarginallywider thanthe transmit pass band, and is thus ideal.Inpractice, therefore, the response will be controlled entirely by the IF filter.I was pleased to see thatitwas not tailoredinany strange way, and in my opinion this helps readability a lot, for tailoring can severely effect intelligibility. I did not notice any VFO drift in prac- tice after a brief warm-up period.

Conclusions

Before giving my overall opi- nion of this rig,I do want to have a big grumble about the instruction book which fails to contain any the publication of this review. often cluttered up with 'bells and block diagram or explanation of the Noting that this design was 2 whistles'.I must admit to preferr- circuitry. I gain the impression that or3years old, I was pleasantly sur- ing theTS530SPto theTS430S, Trio seem to be talking down to prised that almost all the perfor- but this is a very personal opinion. their intending purchasers, and I mance measurements were very It is as a result of considerable de- feel they must improve on this at- good, some beingsuperb. We mand from radio amateurs that Trio titude. I also feel that Trio should couldn't find any parameter that have retained this model in their have provided a transverter drive could really be regarded as poor. If catalogue, and I hope it will remain socket, which is, in this case, after you want a basic rig that has a few available for quite a time. Do not all,only a piece of coax and a extra frills which all work well, then rule out this rig just because it has phono socket. Lowe Electronics you should seriously consider the valves init,for I consider this a have kindly offered to put in the TrioTS530SP.Interfacing is very goodratherthan a badpoint. transverter drive socket and cable simple, and there was no sign of Ergonomically it is very well design- free of charge on application to any problems with the rig. My only ed, and is a worthy little sister for them for any products sold from real criticism performance wise is theTS830and930models. the reciprocal mixing performance, I would like to thank Lowe Elec- but again there are many more ex- tronics for the loan of this rig, and pensive rigs that are worse in this my colleague Mike Hatch, G1DEW, respect. Do not think that because for spending many happy hours theTS530SPhas been on the peeringatallthemetersand market for quite a time that itis oscilloscopescreens.Highly "old hat", forI am much happier recommended then as a sensibly with a rig that has proven RF per- designed rig, particularly useful for formance rather than some 'whiz- driving VHF transverters because bang' modern ones that are all too of its sensible ALC provisions.

TS530 SP Transmit two-tone intermodulation. Upper pic. At 25W output. Lower pic. At 100W output.

40 TRIO TS530SP LABORATORY MEASUREMENTS

Receiver Measurements T Notch Depth (average) Ratio between two tones notched in turn 37 dB Sensitivity for 12dB Sinad, SSB (1kHz beat note) 28.4 MHz - 124dBm (0.14uV) Transmitter Measurements 21.3 MHz - 124.5dBm (0.13uV) 14.3 MHz - 125dBm (0.12uV) RF output Power, CW (after careful tuning) 7.05 MHz - 1 25dBm (0.1 2uV) 3.7 MHz - 1 24dBm (0.14uV) 1.9MHz - 125dBm (0.13uV) 28.4 MHz 100W 24.9 MHz 108W Measured RF attenuator value (at 14.2MHz) 20dB 21.3 MHz 100W 18.1 MHz 105W Selectivities 14.3 MHz 107W 10.1 MHz 102W SSB CW (Narrow) 7.05 MHz 105W 3dB Bandwidth 2.4kHz 0.4kHz 3.7 MHz 112.5W 6dB Bandwidth 2.5kHz 0.6kHz 1.9 MHz 105W 40dB Bandwidth 3.4kHz 1.1kHz 60dB Bandwidth 4.2kHz 1.3kHz 80dB Bandwidth 22.1kHz 8.8kHz RF output power, SSB PEP approx. 120W on all bands.

Reciprocal Mixing Performance Transmitted Frequency Accuracy, CW (28.4 MHz) + 20Hz RF Levels required off channel to degrade Sinad by 3dB (ref. noise floor) Harmonic output (at full power ref. fundamental)

20kHz spacing 86.5dB 2nd 3rd 50kHz spacing 91.5dB 100kHz spacing 94.5dB 28.4 MHz - 48dB - 60dB 200kHz spacing 107.5dB 21.3 MHz < - 60dB - 60dB 14.3 MHz < - 55dB - 65dB RFIM Performance, SSB 10.1 MHz < - 52dB - 63dB 7.05 MHz - 46dB - 65dB Carriers spaced at 100/200 kHz off channel for 12dB Sinad 3.7 MHz < - 46dB - 67dB product. 1.9 MHz < - 45dB - 67dB

RF Level (ref. 12dB Sinad Calculated SSB Residual Carrier and Noise RF intercept - 57dB pt. Unwanted Sideband Suppression, USB 28.4MHz 81 dB -2 dB - 63dB 7.1 MHz 85 dB + 2 dBm 1.9 MHz 86 dB Two Tone TransmittedIntermodulationProducts. (See + 4 dBm photographs) S Meter; RF Levels required to give the following readings Full Power 1/4 Power S1 - 109.5dBm (0.75uV) 3rd Order -25.5dB -31dB S3 - 107dBm (1.0uV) 5th order - 34dB - 54.5dB S5 - 102dBm (1.8uV) 7th order - 52dB - 62dB S7 - 91dBm (6.4uV) 9th order - 73dB - 70dB S9 - 75dBm (40uV) 11th order - 67dB In noise S9 + 20dB - 51dBm (0.65mV) S9 + 40dB - 30dBm (7mV) S9 + 60dB Not Calibrated

SSB Received Frequency Accuracy +/- 10Hz

Product Detector Distortion 0.7% Audio distortion at 1 25mV output (8ohms) 0.7%

Maximum audio output level for 10% THD into 8 ohms 2.1 Watts

Maximum audio output level for 10% THD into 4 ohms 3.3Watts

41 NEXT MONTH

ANTARCTIC DX-INIG FROM VP8ANT Richard Newstead, G3CWI, answered an advertisment in the daily papers and found himself in the Antarctic as VP8ANT

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SCANNING RECEIVERS An investigation by Tony Bailey, G3WPO

HIGH PERFORMANCE 2m GaAsFET PREAMP Interested in DXing on 2m? Then build yourself this innovative design, by John Matthews, G3WZT

QUARTZ CRYSTALS STOCK CRYSTALS MADE TO ORDER CRYSTALS CRYSTALS FOR 2 METRES FUNDAMENTALS OVERTONES HC25 £2.15 FOR ONE CRYSTAL £1.96 WHEN 2 OR MORE PURCHASED FREQUENCY RANGE PRICE FREQUENCY RANGE PRICE HC6 £2.15 FOR ONE CRYSTAL £2.05 WHEN 2 OR MORE PURCHASED 5 TO 50 kHZ£21.00 3rd OVT 21.00 TO 65.00 MHz £4.55 TX CRYSTALS RS CRYSTALS CHANNELS IN STOCK 50 TO 150 kHZ£11.00 5th OVT 60.00 TO 110.0 MHZ £5.10 MHZ £7.40 HC6/U 8MHZ 30PF 44 MHZ SERIES RES : RO TO R7,S11, S20 TO S23 150 TO 500 kHZ £7.80 5th OVT 110.00 TO 125.0 : RO TO R7 S8, TO S23 & S32 160 TO 999 kHZ£11.90 7th OVT 125.00 TO 175.0MHZ £10.00 HC25/U 12MHZ 30 & 40PF : 44 MHZ SERIES RES HC25/U 18 MHZ 25 & 20PF 14/15 MHZ 20 & 30 PF RO TO R7 S8, TO S23 & S32 1 TO 1.5 MHZ£10.75 : RO TO R7 S8, TO S23 & S32 1.5 TO 2.0 MHZ £5.10 HC25 : SCANNER XTLS (NOT SR9) full list available on request please send SAE. 2.0 TO 6.0 MHZ £4.75 DELIVERY 2.070175.0 MHZ2 TO 3 weeks 4 METRE CRYSTALS FOR 70.26 IN HC6/U AT 02.40 each 6 TO 21 MHZ £4.55 TX 8.78250 RS 29.78000 21 TO 25 MHZ £6.50 5 TO 999.9 kHz 6 to 8weeks 70CM CRYSTALS £5.00/pr or £2.50 each 25 TO 30 MHZ £8.50 1 TO1.499 MHz 3 to 4weeks For Pye PF1 PF2 & PF70 series Wood & Douglas and FDK MULTI Ull Unless otherwise requested fundamentals will be supplied for3Opf load capacitanceand overtonesfor series SUB(433.2) SU20 RBO RB2 RB4 RB6 RB10 RB11 RB13 RB14 RB15. resonant operation. ALSO for MULTI U11 ONLY SU12 SU16 SU18 HOLDERS:- PLEASE SPECIFY WHEN ORDERING- else HC25/U suppliedfor XTLSabove3 MHz HC13/U CONVERTER CRYSTALS IN HC18/U AT £2.85 each. 6-200 kHz HC6/U & HC33/U 170 KHz-175 MHz HC18/U & HC25/U 2-175 MHZ 22.000, 38.666, 70.000, 96.000, 116.000, 101.500, 116.000 DISCOUNTS: Price on application for 10+ units to same f requency/spec. or bulk purchasesof mixedfrequen- FREQUENCY STANDARDS £2.75 each cies. We supply FREE xtals for use in U.K repeaters. HC6/U 200kHz 1000kHz 3.50 MHz 5.00 MHz 10.000 MHz 10.700 MHz COMMERCIAL CRYSTALS: available on fast delivery and at competitive prices. Please send for list stating HC18/U 10000kHz 7.00 MHz 10.70 MHz 48.00 MHz 100.00 MHz interests Also HC6/U 200 kHz 455 kHz £3.25 each EMERGENCY SERVICE: for XTALS 1 to 125 MHz. Add the surcharge for each XTAL. Days refer to working TONEBURST, I.F. & MPU CRYSTALS IN HC18 £2.25 EACH days. 4 days +£12,6 days +£7, 8 days +£5, 13 days +£3. 7.168 MHZ (For 1750 HZ Tone), 10.245 (for 10.7 I.F.) CRYSTAL SOCKETS HC25 £0.20 ea. HC6 £0.25 ea. MINIMUM ORDER CHARGE £1.50 unless ordered 3.2768 5.0688 14.3180 15.00000 with crystals YAESU CRYSTALS for FT101's FT9O1 & etc £4.00 each TERMS: Cash with order post Inc. to U.K & irqlend. Cheques& P.O.'s to QSL LTD. Many available ex stock (A list is available on request pse send S.AE.) A stamped addressed envelope with ALL enquiries please. 117artSLabu P.O. Box 19 ALL PRICES ARE Telephone: 01-318 4419 24Hr Ansafone: Erith(03224)30830 gr_st Erith EX VAT PLEASE ADD 15% Telex: 8813271 GECOMS-G (Attention QUARTSLAB) MARKETING LTD Kent DA8 1 LH

TALK TO THE WHOLE WORLD Study now for the Addendum RADIO AMATEUR'S Practicalities, May '84 EXAMINATION The capacitors in Fig. 3 are 10p not 10n. We have had 40 years successful experience in training men and women for the Active Aerial, June '84 G.P.O. Transmitting licence. The capacitor in series with the antenna is mica. All the FREE R.A.E. brochure without obligation from: - 1 other capacitors could be polystyrene except the iOn and 100n, which are ceramic. British National Radio & Electronics School I READING, BERKS. RG1 1BR Plain Man's Guide To 6m Reception, June '84 This was missed off the contents page by mistake. IName Address Plain Man's Guide To 6m Reception, June '84 I This was missed off the contents page by mistake. L HRT/7/846 BLOCK CAPS PLEASE.'

42 HAM RADIO TODAY JULY 1984 This is LPTilat=0) HO 000 When Ifirst heard about G3UPK's wereto seeofheruntil

Trans South American journey I Montevideo,Uruguayon 1st was immediately interested in get- February 1982, the beginning of an ting him to write an Amateur Radio adventure during which this plucky flavoured travelogue for HRT. He little 4 cylinder diesel van would hadtaken anAtlas215X HF take us over a dozen passes in the transceiver with him and reports Andes and Rockies,5 of which had filtered back to me of Roger wereat 15,000ft,andover working UK stations with a 1/4 wave thousands ofmilesof unsealed

.1, Roger Crofts, G3 UPK (ex ZD8A Y, ST2AY and - 1;10.4 VK6 YA to name a few), and Mary Carpenter set out on a journey that was to take them the length and breadth of South America. This is their story, seen through Mary's eyes.

'whip' antenna made of wire sup- roads. One set of tyres was to suc- ported by a piece of the Brazilian cumb to the sharp gravel roads of Myrtle with 'twig' antenna jungle (you mean a 'twig' - Ed. Patagonia and another to the attack CB). of Mexican prickly pear thorns. (/ is no water, no-one seems very con- I wrote to Roger's home ad- don't have this problem mobile on cerned about it!This 'manana' at- dress only to find that he was out the Ml - Ad Manager G4NXV). titude was difficult to accept at first, of the country on business,in After delays and hold-ups with but obvious right through to Mexico. Cameroon, Africa. His father kindly the shipping company, we were wrote back to me and said he told finally when the ship would ar- would pass the letter on to Roger rive and flew out to meet it, chang- Myrtle Arrives who would be in Africa for some ing planes atParis, the last we months yet. However, shortly after would see of wonderful Europe for The ship with Myrtle aboard final- this, I received a letter from Mary 16 months. There was alarm when ly arrived but, as our home -on -wheels Carpenter, Roger's girlfriend, who only my bag arrived as Roger's bag was being unloaded by crane, we had shared the journey with him. contained his camera, binoculars could already see that the thieves had Roger's father had told her about and the ham radio gear among the got to her. Myrtle's side window had my request. She had kept a careful important items! The lady at the been force. The thieves were pro- diary of the journey - would Ilike airline office was very helpful,a bably disturbed in the act, as our her to write the journey up for trait we found almost everywhere sleeping bags and various items were HRT? LookingatMary'sprose in Uruguay, and a few days later scattered about on the floor and we style, I decided to tell her to go thebagreappearedminusits had lost only a few unimportant ahead. handles but with all its contents in- things. The jemmy marks are still a Thisis the result.Itperhaps tact. Not unexpectedly the ship br- reminder of the determined but isn't what readers usually find in inging our car had been further ultimately unsuccessful attempt to HRT inasmuch that Mary is a radio delayed in the meantime. get into the main cupboard. With for- spectator rather than an operator So we had to stay for 10 days in a malities completed, we waved good- and the emphasis in this article is pension, run by a kindly middle-aged bye to our friends and headed east to on the travel rather than the radio. couple who spoke no English (the Punta del Este and Fortaleza de Santa That being said, I hope you all enjoy case we found through most of Latin Teresa, only to be pulled up by three readingthisas much as I did. America) - and our Spanish was very traffic cops for overtaking in a forbid- G3ZZD poor at that stage, too - though we den zone. After much persuasion, tell- On acold December day in enjoyed our stay there. It was an old ing them it was our first day on South 1981, we dropped off Myrtle, our place, cheap enough, the best part be- America roads, and with the Customs 1974 LWB land Rover, at Harwich ing the hot water shower! I need not sticker still glued to the front window, Port which was partially covered elaborate on the plumbing which we they let us off with a reprimand, with snow and iceafter recent found the same in most places in Latin saluting us courteously before bid- snowfalls. That was the last we America. When the toilet blocks there ding us "Buen Viaje" (Good journey). D HAM RADIO TODAY JULY 1984 43 Unfortunately this good police at- the war ended and, just off the titude was not to be found in many Belem-Brazilia highway, we toasted other parts of South America. the victory with champagne (on ice Uruguay was our first South sinceRio, two monthsearlier). American country and the best one by Twice we visited Rolf, PY1RO, a our experience. We then spoke very very keen and well known 160m little Spanish and Ishall never forget operator, and his charming wife, the kindness of most of the Rosangella. She spoke little English Uruguayans we met. We crossed to and we no Portuguese but we en- Argentina over the huge Uruguay joyed marvellous hospitality with River at Fray Bentos (Corned Beef churrascarrias (Brazilian barbecues) Country! - Ed) on 8th February, andtripstobeautifulbeaches, passing through mosquito ridden someofwhichwe camped swamp country, south to Buenos peacefully by for days while sun- Aires, where we spent five days with bathing and catching up on odd an Argentine friend. He and his lovely tasks which never seem toget wife extended us wonderful hospitali- done whilst on the move. While in ty and delighted in showing us places Brazil, we had a great reception of interest by day and night, taking in from Europe on 14MHz. From the restaurants with one inch thick beginning of May, Roger made con- steaks, a tango show with wonderful tactwithEddie,G4KHG,and dancing and music, and theatre Frank, G4HBI, almost every night, shows which appeared to be cen- up till we reached Florida at the end sured by the military Government. of September, 1982. After this The people of Buenos Aires are proud reception deteriorated, Europe cut of their cosmopolitan city, which out by the seemingly thousands of boasts as many theatres as London or North American stations on -the -air. New York and more taxis than either of them. People eat very late and the Viva Gran Bretannia restaurants are packed after mid- night. If you think parking in UK is bad, We missed Frank and Eddie you should try Buenos Aires. Parked very much for the remainder of the cars are literally bumper -to -bumper in trip. They were such fun to speak every street anditis always with and we had some hilarious and necessary to shunt several of them to tense moments when some irate make a little room to get in or out. Argentinian stations would come Driving a Land Rover has distinct on -the -air,abusingtheFalkland advantages! Islanders, British and anyone else who supported them. But, from the Southern Travelogue Oro Preto, Brazil point when we crossed to Paraguay over the Parana River, most of the After Buenos Aires we headed fuschia flowers which grew in wild people we met in Bolivia, Peru and south across the pampas, visited a profusion. From Osorno, passing Ecuador applauded 'Gran Bretan- sea -lion colony on the Valdes Pen- snow-capped volcanoes, north to nia'. There seems littlelove lost ninsular, the petrified forest near Santiago to cross the Andes again between the South American na- 16th March, Sarmiento,andenjoyed a real atLas Cuevas on tions. Another example of this oc- Welsh tea in a quaint tea -house in- (already snow on theground!) cured while we were watching the Gaiman, a town in the old Welsh down to Mendoza (a popular wine World Cup, Brazil v Italy match on colony where the people still speak area of Argentina) and back to Welsh. We arrived in Ushuaia, the Buenos Aires.It was a very quick Mt. Salcantaz, Peru most southerly town in the world, departurenorthon 1stApril, on 25th February at the height of heading for the Iguacu Falls and the theirsummer,althoughithad next day we heard on the BBC of snowed the previous day. In Tierra the invasion of the Falklands. There del Fuego we battled through the was dancing in the streets and the strongest winds we have ever en- blue and white Argentine colours countered as Patagonia is known flying from every car and house. for its winds and, no matter in what We were lucky toget through direction we headed, they always numerous military checks and safe- seemed to be against us! We then ly onto a the ferry across the Iguacu made a very worthwhile detour to River to Brazil on 5th April. themagnificentPeritoMoreno glacier and on into the beautiful lakes district. The Puyehue Pass in- On -Air In Brazil to Chile was another amazing ex- perience, the vegetation being ex- We then spent three months in tremelybeautiful,especiallythe Brazil, keeping a low profile until

44 HAM RADIO TODAY JULY 1984 Street urchins from Rio de Janeiro, Brazil an open air TV in Ascunsion. We thoseinpower set against the few ranchos and three vehicles- were surprised when everytime the gentleness and humbleness of the and no signposts! Italians scored, the Paraguayans lowerclasses,madeitselffelt Stoppingforthenight, we went wild with joy. Meantime, in through all Latin America, especial- camped just off the track, hidden in Brazil,the hospitals were being ly in Andean countries. About this thethickeningvegetation,and overwhelmed with cardiac patient time, Roger realized he was not ful- heard on the BBC World Service We had Myrtle's engine servic- ly equipped for the cold of the ap- that a coup had taken place that ed because Paraguay is the only proachinghighAndes. Theair day in La Paz, the capital. Later, we SouthAmericancountry where waves hummed withurgent heard the droning of engines and anyone has heard of Land Rover. messages and the knitting needles saw headlights approaching. We There was 19,000 miles on the of G4HBI's Mum were set into ma- switched off the inside light and, clock since Montevideo. On the tion.In next -to -no -time, a pair of peering through Myrtle's little roof next stage of our journey we were extrathick,high -altitudetype, window, we saw a convoy of army held up, first, by unseasonal rain, woolly socks were winging their trucks, packed with heavily armed which washed out the road for way to Bolivia! soldiers, grind past. They were go- several days, and then by soldiers ing becauseofthecoup we demanding gifts. After spending a Cassette And Run thought. Butit was such a long night under military guard, we were wayacrossthemountainsto ordered to take two officers and a At thenextcheckpoint we Sucre,letalone LaPaz. Where soldier's wife to the border out- reached, the officer who lived in could they be going way out here at post, a day's drive down the track. the adobe hut was after music (so this time of night? . . There was much handshaking and he said). He spotted our cassette Next morning from our camp, backslappingwiththeirmilitary player and there followed a detailed we could see the beginning of the friends at each checkpoint plus a search. The HF transceiver was of majestic Andes once more. The last quick stopforlunch along the no interest but his eyes lit up when time we had seen then was from otherwise deserted track, which he opened our box of cassette Argentina.Theweather was reminded me of the Austalian Out- tapes. We begrudginglyparted gorgeous.Beingstillin the back. This land was the scene of a with"TheCarpentersGreatest lowlands,it was fine with clear bitterandbloodywar,fought Hits". "That's her name", said the blue skies and the night had been against Bolivians earlier this cen- officer, pointing at me. "We have a warm and balmy, such a contrast tury in the mistaken belief that oil cassette player but no tapes", he to the humidity and rain of much of lay beneath the infertile surface. explained-whichmade us Brazil. At Boyuibe town we were By late afternoon we reached wonder if that, too, had also been escorted to meet the (local) Col- theborderoutpostandour procurred from some unsuspecting onel, who invited us for lunch con- passengersleftuswithout a travellers like us. They insisted on sisting of delicious vegetable soup backward glance or "gracias", ex- hearing the tape played and the of- followed by salad. The other of- cept for the wife, a young, part ficer tappedhisfinger and the ficers present were courteous and Guarani, Indian girl, with a gap in soldiers danced completely out -of - the Colonel was proud to show off her front teeth as so many of the In- step to the music, but none -the - hisEnglish,dismissingourat- dian people seem to have. She less, they pronounced it good and tempts to speak Spanish. The Col- politelyoffered us a delicious gave us back our passports. The onelhad hopedthathe might grapefruit, and her husband, who pleased officer even drew a small change 1,000 dollars of our money was there to meet her, thanked us map to the next town, Boyuibe, as for us but accepted the 100 dollars for bringing her safely home. This from then on the country was very that we wanted to change willingly extremityofcharacter,theag- isolated. In the 11/2 days it took us enough.Itturnedoutthat gressive arrogance of the rich and to get to Boyuibe, we passed only a everything in Bolivia was so cheap

HAM RADIO TODAY JULY 1984 45 that 100 dollars was plenty for our cold and rarified atmosphere, star- Goodbye To two week stay. Diesel, for exam- ting the engine was a real problem South America ple, was only 12p per gal. and even with aerosol ether. The solu- petrol not much more. tion was to park Myrtle facing east After Boyuibe it was into the After the month inPeru, we and lift the bonnet before taking crossed into Ecuador at the noisy, mountains,climbinghigherand breakfast. The early morning sun filthy, border town of Huaquillas. higher up to the Altiplano, never luckily did the rest. leaving them until Nazca on the We had virtuallyno trouble There are, invariably, at least three coastal plain of Peru (OA). It took with the military in Peru but found policemen at every road junction in four days to reach Sucre, one of the the civilians the opposite of the Ecuador. One signals you to stop, best kept old Spanish towns in Bolivians. We remembered that the whilst anotherfrantically waves South America. We had to wait Colonel and his officers had told us you on. A third makes such am- here six days to pick up our mail as the Post Office was on strike. The that the Peruvians were "mucho biguous signals that you don't have restaurants were so excellent and loco". The were right! We only a clue what he means. Whatever cheap that we ate out every night once had occasion to use public you do, you are bound to be wrong. but always returned to our seclud- transport(thank heavens), from It's good idea to take several driv- ed camp site in a eucalyptus forest, 011antaitambo to Machu Picchu, ing licences as these are frequently on one of the hilltops overlooking the famous Inca ruins, by train, which arrived five hours late and torn up into little pieces and scat- the town. Our only visitor there tered allovertheroad.The a Indian packed. After arguing with, and be- wasAlfredo, little Ecuadorians have built a monument shepherdboy, who stayedfor ing thrown off the train by the con- lunch, consisting of sandwiches, ductorsinthefirst and second to mark the exact and precise line tea, and cracker biscuits with mar- class carriages (we had first class of the equator, just north of Quito. mite. The marmite was, of course, tickets!), we eventually jumped on We visited the monument and also new to him and he loved it. Later he to the outside of the train and hung theequatoritself- whichis went home and we were surprised on, as the train slowly chugged out located a little bit further on! From when he returned half an hour later of the station, leaving many people Ecuador we shippedMyrtleto carrying an armful of maize for us behind,includingthreeEnglish Miami whilst flying ourselves but, and insisted on putting some of it back -packers, who vehemently at the time of writing, we still have on the gas to boil, which seemed to cursed Peru Rail!I was also suffer- not reached our goal of Alaska. take ages, as it was very hard, the ingfromaltitudesickness and This we hope to do in July 84, but onlyvarietyabletogrowat faintedupattheruins,while 10,000 ft. waiting for the fast bus to take us that is another story. back down the thirteenhair -pin Potent Cheap Music bends(I'llsticktothe M1 - Roger and Mary arepresently G4NXV) to the station below. After finishingtheirTransAmerican We enjoyed a concert at the two failed attempts to revive me journey. This time Roger has equip- local theatre of the delightful music with smelling salts, I recovered in ped Myrtle with a 1KW amplifier for of the Andes, produced, in part, by the little clinic after oxygen was ad- the Atlas 215X. Look out for him that exquisite instrument, the pan ministered by a kind nurse. The on the American County Hunter's pipes,thehauntingsoundsof train back was four hours late and net on 14.336MHz from 1400 which conveyed to meallthe total chaos, as about 200 tourists heaviness, sadness and suffering UTC onwards. A further instalment and Peruvians fought their way on- should be appearing in a future of the life of the South American In- to an already packed three car- HRT. . . dian. Cost of the two hour concert? riages. - around 5p each. From Sucre it took two days to On the shores of the iceberg filled waters of Lago Argentino, Patagonia, reach Cochabamba, in a warm and Argentina dusty valley that produces an abun- dance of fruit and vegetables. That was the last of the warm weather, for the next day we climbed the two miles to the barren windswept Altiplano. We spend the first even- ing in a blizzard, parked near a lake by the deserted roadside, deep in our sleeping bags, gloves and caps to combat the bitter cold. The next morning there was a covering of snow and the lake had frozen over. Just down the road a truck full of Indians had broken down. None of them were wearing gloves, and they had only sandals on their feet - the hardiness ofthese people never ceased to amaze me. In the

46 RADIO TODAY JULY 1984 A Plain Man's Guideto IDuo OMcon

This article is the sequel to my arti- back on 2 metres or 7 0 centimeters known terms a seriesofother cle in last months issue which in- - to enable him to take his report terms which lie outside the range of troduced thereader to"Fifty", direct from you on a band you are the known terms". This exactly fits meaning50 MHz,meaningSix entitled to use. the concept of the intended con- Metres. It will take this expedition a So much by way of foreword. verter for 6 metres. It is a venture into the (comparatively) unknown, 2m and 70cm seem a little familiar these days? You and it lies outside the range of our could try exploring 6m or 4m with this intrepid little "known terms". converter from VHF guide Jack Hum, G5UM. Simple Fig. 1 : The basic concept of the "Extrapolator" converter describ- step-by-step construction without even denting the ed here is shown in block form, bank balance. crystal oscillator at right, RF stage at left, each of them feeding its out- few stages further, but, most im- put to the mixer stage, centre, to On now to the world's simplest give output at 5 MHz. portant,itwillintroducethe converter for use on "Six".Itis simplest -ever converter forcon- calledtheExtrapolator,a name struction by those wishing to essay which perhaps requires a modicum "Six" for the first time. of explanation. Before getting that far, though Look in the dictionary for the a comment on a query which a definition of "extrapolate" (accent number of people have made. Itis on the second syllable) and you will this: "Am I allowed to listen on the finditto mean: "Calculate from 6 metre band?". The answer is simple: "Ofcourseyouare". Wearing his VHF field day headgear, Anyone isallowedto listen Author G5 UM contemplateshis anywheretheylikewithinthe amateur radio first mock-up prototype of the "Ex- spectrum.Ifthis trapolator"70/50 MHz converter were not so, how would, say, the described here. budding Class B aspirant to the so- called HF bands ever acquire any knowledge about them if he never listened on them? (You could say thatifhe didlisten on them he might be dissuaded from wishing to use them, but that's another story). It should be emphasised, then, that even though you may not be licensed to transmit on 6 metres (or, for that matter, 4 metres) there is nothing to stop you from listen- ingthere. You may report back what you hear on those bands, but you must do so on a band for which you are licensed. Never embark on a crossband contact with a station using a band which you are not per- mitted to use. Put another way, this means that if a local friend asks you, as a Class B licence holder, to give him a report on his emissions on 4 metres or 6 metres, tell him that you will be glad to oblige, but emphasise that you must meet him

HAM RADIO TODAY JULY 1984 These "known terms" are represented by any existing con- INTERSTAGE verter design for the 4 metre band, SCREEN and their number is considerable. (SEE TEXT) We could take a known 70MHz three -transistor converter and by alteringitsinductor andcrystal values, changeitintoa 50MHz converter. You extrapolate from theknown(70MHz)intothe unknown (50MHz). Something else we needin addition to our extrapolation device istoprovideourselveswith a reasonably adequate aerial system for "Six", a requirement which was dealt with here last time. Often one is told by newcomers to the 433MHz band that they are press- ingintoservicetheir145MHz antennasratherthaninstal something that will do justice to 433MHz - and then, wondering why their results on 433MHz ap- pear to be so dismal, they abandon the band without having given it a real chance. The same thinking applies to "Six". Maybe the sizeable beams, big as a Band 1television aerial, +12V LINE which would do justice to the band Fig 2: Circuit layout of the "Ex-dicated at "FT". The 12 V + lead is are beyond your pocket - and your trapolator" converter constructedto be connected to one of them backyard space: but at least instal on a 41/2 by 31/2 inch rectangle ofabove chassis. Below chassis the somethingthatis resonantat printed circuit board intended to fittwo feedthroughsareintercon- 50MHz ratherthanattemptto into the top of an Eddystone die-nected with a length of bare wire, make do with something which cast box. The first components towell scraped and cleaned for good isn't. be mounted should be the twocontact. This is the busbar to which feedthroughcapacitors,oneatgo the various feed resistors from What IF To Use? each end of the assembly as in-oscillator, mixer and RF stages. Back to the converter, then. Remembering that its output is to for that workhorse the BF1 80, and be presented to the station receiver signal with a localoscillatorat used as a tunable IF, the construc- 22MHz: theIF would then have a visit to the emporium of Frank tor must decide at the outset what been the 28 to 30MHz band. Some Elliott(ElliotElectronics) not far value of intermediate frequency he readers may prefer thisIF to the from the home base produced a have seenhis wishestoemploy. The options 5MHz in the present design. fistful(youwill in the weresetforthherelasttime. As will be seen, to select one's regularadvertisement Although the "Extrapolator" uses IF is to select one's required crystal 'Emporium Guide' in HRT). 5MHz as its IF, there is no reason value, 45MHz in the present in- Many would-be constructors will wish to use what they have to atallwhy readersshouldnot stance. Contact with Bruce Norclife choose a different one if this should at P.M. Crystals (whom G5 UM has hand in their spares boxes such as ubiquitous suittheircircumstances.One used for many years) established theold-timebut elegant professionally designed 6 that 45MHz crystals were stock 2N708, ZT81 and the like, which metre converter provides an IF in items. Within days one appeared in though elderly should loaf along at the amateur 2 metre band by mix- the morning's mail, complete with the comparatively DC frequency of ingthe incoming 50MHz signal tiny plastic socket using lOmm pin 50MHz. "Using what I've got" is with a local oscillator frequency of spacing and centre -fixing lug for one of the rewarding features of 95MHz, and by this additive pro- printed circuit board mounting. any home construction project. cess up -converts to 145MHz. Next item on the construction The "Extrapolator" by contrast agenda was: What oscillator circuit Layout Considerations presentstheincoming 50MHz to use? The number of options is signal with a local oscillator value legion. The sure-fire one shown in Before construction can com- of 45MHz and by a subtractive pro- Fig 3 was adopted for the presert mence,thefollowingquestion cess down -converts to 5MHz.It project. And what transistor to use assertsitself:Whatformof could have presented the incoming with it? The writer has a penchant mechanical design layout should be

48 HAM RADIO TODAY JULY 1984 employed? If you are into PCBs and quire a 12 volt positive supply. tant, a description of what each the photographic -and -etching pro- component does. cesses of the contemporary scene, Take One Oscillator.. . Letconstructioncommence! you may well prefer to use them. If Lay resistors and capacitors on the you are not - and this article is ad- Down the years the custom at insulated side of the PCB so that dressed to the thousands of HRT G5 UM when building converters is their wire ends may pass through readers likely to be in that category to start with the oscillator section. holes on to the copper -clad upper - then the following simple layout One knows "clever devils' who are side of the PCB where they are to is recommended: able to start with the RF section be grounded, or to the "HT Rail", Purchase from one of the HRT andworkwithinsolentease the feed through capacitors where components advertisers an Eddy- through the mixer section and build they are to accept the +12 volt stone (orsimilar) aluminium die- the oscillator section last.If you supply. The tuning capacitor C3 cast box measuring 120 by 95 by have the expertise, fair enough, do and it's related inductor L1 are the 50mm deep. You will not need the it that way in the present instance. largest components and should be lidforthe"Extrapolator"con- If you don't then play safe and get mounted first. When soldering in verter, but keep itlestitshould the oscillator going first. It's posi- thetransistor,gripitslead -out come in useful for some future pro- tion on the PCB chassis is shown in wires with a pair of long nosed ject. The space occupied by the this half-size diagram, Fig 2, which pliers which will act as a heat sink metal lidis to be filled by a rect- gives an idea of the compact con- and prevent the heat of the solder- angle of single -sided PCB cut to fit struction of the unit. ing iron from killing the semicon- the top of the die-cast box. If you In Fig 3 is shown the 'sure-fire' ductor. already have some PCB you can oscillator circuit referred to earlier, With construction of the CO mark off the required dimensions in complete with a table of compo- stage completed, it is time to plug, pencil and then carefully hacksaw it nent values, and, equally impor- in the 45MHz crystal and to rotate to fit the box. If you don't, then ask your supplier if he can do the job for FIG 3: The "Extrapolator" converter you when you buy the box. crystal oscillator stage: Radiusthecornersofyour newly acquired piece of 'raw' PCB 0 +12V to fit the radiused angles of the die- cast box. Drill 4BA holes in each R3 corner - to secure the PCB to the box when the converter to be built upon it is completed. Single sided PCB is to be used, C1

as I have saidpreviously.This allows components to be mounted C3 L1 R1 on to the insulated side of the PCB (to face downwards). The copper clad side is to face upwards. Small 101 TO ..4.._.___I I holes are to be drilled in it through MIXER XTAL which will pass the wire ends of C4 those components (beneaththe b PCB lid) which need to be ground- Q1 ed.Inaddition to these earthing points, the only items visible on the R5 0 top face of the PCB will be the R2 coaxialsocketforaerialinput, another coaxial socket for IF out- R4 C2 put, the IF transformer, and a cou- pleoffeed -throughcapacitors. 0-12V From one of these will extend the /13// + ve DC supply lead, a length of red wire. The - ve DC supply lead, a R1 22 Kohms and R2, 12 Kohms, FT 2 ,200 pF feedthrough capacitor, lengthofblackwire, istobe base bias network. feed -line decoupling soldered firmly to the edge of the R3 750 ohms, collector output L1 inductor to resonate with crystal copper laminate on the top face of decoupling. X: approx 12 turns of 24SWG the PCB. At extreme right of the R4 2.2 Kohms, emitter bias. enamel or dcc wire close wound R5 150 Kohms, mixer input load on 3/4 -inch former fitted with iron PCB top the tiny crystal socket is dust core alug. mounted. (see Fig. 2 which shows resistor C1 1,800 pF, collector output X crystal, 45MHz, for 50MHz the PCB from the 'lower' compo- decoupling version, 65 MHz for 70 MHz nent side). Beneath the PCB the C2 1 ,800 pF, emitter decoupling version. two feed-throughs will be intercon- C3 0-15pF miniature trimmer (3 Tr 12 N708 , ZT8 0 /81, BF180 or nected with a length of stout bare plate + 4 plate), collector tuning similar wire.To this'HTrail'willbe C4 5pF, coupling to mixer input. soldered those resistors which re-

HAM RADIO TODAY JULY 1984 49 C3 to induce oscillation. B "But how shall I know if the stage is oscillating?". The question is a basic one. A few lucky readers who possess a receiverwith 45MHz in its tuning range will ac- tually be able to listen on that fre- SHIELD quency for the oscillator 'starting up'. For everybody else a visual 2N708, ZT80, 81 etc BF180 means of observing that the CO is FIG 4: The "Extrapolator" crystal oscillator stage may employ any one of functioning is essential. This is how a variety of readily available transistors. Base connections of a typical to go about it: examples are shown here. Insert a low reading milliameter or multimeter set to a low DC mA range in the 12 -volt -plus lead and for transistor Tr1. when a 2N3819 is used, and Fig rotate the preset trimmer C3. A 5(b) with a BF981 MOSFET. The change in the standing current will ...Next, Mix Gently latter improved both performance be noted when oscillation starts. and oscillator isolation. Touch the crystal socket with the As with the oscillator stage so In the IF output circuit, the in- fingers: the standing current will with the mixer: several configura- ductor resonating at the IF of 5MHz have afew change again because oscillation tions suggest themselves. Earlierwouldtraditionally convertersbuiltatG5 UM have turns of wire wound around its ear- has probably stopped. thy end to provide a low impedance In the prototype converter, the employed the ubiquitous BF180, is the 65MHz crystal used in the 70MHz and indeed the initial layout of the output. Lesstraditional version went into oscillation with present project used it. capacitor output network shown in the C3 trimmer almost fully out and A change to one of the earlier Figs 5 (a) and (b). It was suggested FETs,the 2N3819, provided a to the writer many years ago by the ferrite core of the inductor bare- G8ACE, has been incorporated in ly in. Extrapolating from 70MHz to useful reduction in converter noise many home built converters since 50MHz after changing the 65MHz compared with the BF180. Why crystal for the 45MHz one, it was not, one argued, use a device a then, and offers the advantage of a two -terminal IF output instead of a found that the trimmer needed to dozenyearsyoungerthanthe be almost fully enmeshed to pro- 2 N381 9? Why not, in fact, try the four -terminal one. It duce oscillation 20MHz lower in BF981small signal MOFSET? Now heat up.. . frequency, and the ferrite core fully was found to be readily available at in. a modest price in the Ambit Interna- At this point, by interconnec- In the circuit diagram at Fig 3 tionallist issued with HRT earlier ting the oscillator of Fig 3 with the thecouplingcapacitortothe this year. Four samples were ob- mixer of Fig 5, the constructor will following mixer stage is included, tained to evaluate their worth both have a ready -to -work converter to along with the mixer input resistor. in the mixer and in the RF stage of hand but by no means a 'hot' one. Itis important that the oscillator the present design (two in use, two Add astage of RF heating'by should be checked with these com- spares just in case of fatalities). preceeding the mixer with a high ponents in place to provide a load Fig 5 (a) shows the mixer layout gain front end amplifier and the

0+12V Fig 5 (a): The "Extrapolator" converter mixer stage using a 2 N3819 FET: C5I R7 R5 150,000 ohms mixer input load C11 resistors. /warl R6 2,200 ohms source bias IF OUT resistor. C9 R7 100 ohms IF inductor feed L2 resistor. C10 C4 5 pF coupling from oscillator. // I/ C5 2 ,200 pF feedthrough HT decoupling. C6 1,800pF source decoupling by- pass capacitor. C71 C4 as Fig 3 C7 33pF gate circuit blocking FROM capacitor. Q2 LOCAL C8 0-15pF preset trimmer, mixer in- I FTS2ILOSCILLATOR put tuning. L4 L3 C9 320 pF, IF inductor output net- work. C8 C10 47 pf IF inductor output network. R6 C6 R5 as Fig 3 C11 1,000pf output coupling to IF output socket

50 HAM RADIO TODAY JULY 1984 O+12V

R10 R7 C11 Fig 5 (b): The "Extrapolator" converter IF mixer stage using a BF981 MOSFET: R7 100 ohms IF inductor feed IJOUT resistor. C9 R8 100 ohms source bias. L2 R9,both 100,000 ohms, gate 2 C10 R10 bias.

C8 0-15pF preset trimmer, mixer in- put tuning. C9 320pF, IF inductor output net- work. C10 47pF, IF inductor output net- work. C11 1,000pF output coupling to IF C8 Q2 output socket. C12 4 .7 pF local oscillator injection to Gate 2 (in this configuration C4 above is not required). R9 R8 C131 ,800pF source decoupling by- C13 pass capacitor. Inductors: See Table 1.

0 FROM LOCAL OSCILLATOR converter is ready to do justice to aerial input socket so that it would be necessary. The prudent con- itself - and the reader's efforts in not be in the same plane as the RF structor nevertheless may wish to making it. stage output coil. Self -oscillation of mount a strip of copper foil at this This RF stage like the mixer is this stage was thus avoided. No point, so that input coil does not to bea BF981and thecircuit screenacrossthe RFstage 'see' output coil. If such a screen is diagramisgiveninFig 7, quite MOSFET connections was found to provided this need measure more straightforward and no frills. Coupl- ing to the mixer stage is from L4 in- to L3, the two coils close -coupled. TABLE 1 Their constructionisleftto the readersingenuity:they may be The "Extrapolator" 70/50MHz Converter: inductor details. wound end -to -endon a single Ll to resonate with 65MHz and 45MHz crystals. Approx 12 plastic former fitted with a separate turns of 24SWG enamel or dcc wire close wound on ferrite core for each with which to 1/4 -inch former fitted with iron dust core slug. peak them up at mid -band. Or they L2 IF output coil, 65 turns on 1/4 -inch former to fill3/4 -inch. may beair -spaced, wound Wire size 28 to 32SWG. Former fitted with adjustable separately and positioned in close ferrite core. proximity for maximum coupling L3 mixer input inductor:70MHz 11 turns 28SWG between them. enamelled on 1/4 -inch former, or The 12 volt feed to the BF981 self-supporting. drain is via a small RF choke. It so 50MHz 19 turns as above. happened that the G5UM spares L4 RF stage output: 70MHz 13 turns 28SWG box contained an old 1.6MHz IF enamelled on 1/4 -inch former, or coil that was small enough to be ac- self-supporting. commodated on the compact PCB 50MHz 24 turns as above. layout of the converter. L5 aerial input inductor: 16 turns 28SWG enamelled on 1/4 -inch former (fitted ferrite core). Although the functions of the Aerial input tapping 2 turns from remaining components are describ- earthy end, Gate 1 tapping 11 ed in the table of values, a word of turns from earthy end. Coil explanation about the aerial input resonates to 50MHz with slug full inductor is necessary. This compo- in and to 70MHz with slug nearly nent on the G5UM prototype was full out. positioned vertically close to the

HAM RADIO TODAY JULY 1984 51 than 1inch tall by 2 inches long. Solder an inch of wire to each of its ends, pass this wire through holes TABLE 2 drilled in the PCB, and solder the wire ends to the top, copper sur- Your "free" signal generators for "Six" face of the PCB. Television Channel 2 vision: 51.75MHz (just within the Aerial input is via a Belling -Lee amateur band). typecoaxialsocket.Fromthis Television Channel 3 sound: 53.25MHz (1.25MHz outside socket half an inch of bare wire ex- the band). tends to a tapping two turns from Television Channel 2 sound:48.25MHz (1.75MHz below the the earthy end of L5. Gate 1 of the amateur band). MOSFET is also connected to L5 at Beacon GB3SIX: Anglesey, 50.02Mhz a tapping 11 turns up.If enamel wire is used to wind L5, ensure that Your "free" signal generators for "Four" the enamelisscraped away at Cornwall beacon GB3CTC 70.03MHz these two tapping points and that Sussex beacon GB3WHA 70.04MHz they are well tinned before attemp- Buxton beacon GB3BUX 70.05MHz ting to solder the tappings to them. Angus beacon GB3ANG 70.06MHz As will be seen from Table 1, Irish beacon EI4RF 70.13MHz this input coil is close -wound on a * Presently off -the -air due to site problems. quarter -inch former fitted with a ferrite core. This single inductor is good for 70MHz as well as for 50MHz without any change. For should be noticed as capacitor C8 50.02MHz, beaming west from the higher frequency the core will is adjusted and all coil cores slowly Anglesey. The signal from GB3SIX be almost full out and for 50MHz, turned within their inductors. over much of the UK mainland is so almost full in. Achieving converter hiss is one marginalthatevenexperienced thing.Homing -inon a reallive navigators of the 50MHz ocean All Ingredients In signalis quite another. Where to reportitas rarely audible. What One Vessel.. . find one? If the 70MHz version of hopes, then, have people like the thiks converter has been built, the writer and perhaps most of the The three stages of the 'Ex- question is answered by the word: readers of this article who merely trapolator'converterhave now 'beacons' (See Table 2). One of paddle on the edges of that ocean? beendealtwithindetail.No these beacons, high in the hills of Nil desperandum: all is not lost diagram of the complete unitis Derbyshire,is GB3BUX, available by any means. Available on "Six" necessary: the inter -connection of all day on 70.05MHz and audible there are many permanent signal the three is self evident from Figs overmuchofEnglandif a generators that will assist the align- 3, 5 and7and a suggested reasonable aerial is used. When the ment of the 50MHz of this con- physical layout is at Fig 2. 65MHz crystal is in position in the verter. They are called television The moment has cometo converter and the station receiver broadcast stations! Three of them check that all the ingredients have setto5.05MHzthe GB3BUX with frequencies near the 50MHz come together happily and that the beacon is likely to be detectable. If band are listed in Table 2. Let us result is "a tasty dish". To do so it is not, switch receiver BFO on to take a closer look at how they may proceed as follows: listen under CW conditions. Finally, be used: Connect a short length of thin readjust capacitors and ferrite coils After the converter prototype coaxial cable from the output IF intheconverterformaximum hadbeensafelybreechedon socket on the top face of the con- signal from GB3BUX on "Four". GB3 BUX on the 4 metre band, its verter to the input socket of the With 6 metres a different set of parameters were extrapolated to stationreceiver. To minimiseIF circumstances prevails. There is at the 6 metre band by the simple ex- breakthrough, bond converter to the time of writing but one UK pedient,alreadydescribed,of receivergroundterminalvia a beaconavailable,GB3SIXon changing the crystal from 65MHz separate lead. Fig 6 (b) Connections to the BF981 Connect a 9 volt or 12 volt bat- Fig 6 (a) Connections to the 2 N3 81 9 tery pack to the converter via the GATE 2 black lead which has been soldered to the upper, copper face of the PCB and via the+ ye redlead which extends from one of the feed -through capacitors. Plug in the 65MHz crystal and set the station receiver at 5MHz. At once an increase in the receiver's noise level should be evident, to tell the constructor the joyous news that the converter is working. A further increase in conversion noise

52 HAM RADIO TODAY JULY 1984 TO L3MIXER

Fig 7: The "Extrapolator" converter r.f. put). R11R1 100 ohm source bias. stage. using a BF981 MOSFET. C161 ,000 pF source bias decoupling. R12 47,000 ohms gate 2 bias. C8 mixer input tuning as Fig 5. C17 1,000 pF gate 2 bias decoupling R13 68,000 ohms gate 2 bias. C14 18 pF, drain circuit blocking C18 18 pF input tuning (select for R14 100 ohms drain feed resistor. capacitor. maximum signal output) RFC drain feed choke (see text) C15 6 .8 pF output stage tuning FT feedthrough decoupling, as Fig Inductors: See Table 1 (select for maximum signal out- 5. to 45M Hz and replacing inductors within the 50-52MHz band. You facilities. It has assumed that very L3 and L4 for the larger size ver- may be fortunate enough to hear few readers will have access to sions shown in Table 1. The station oneifyou tuneslightlyabove professionallybuiltsignal receiver wassetat6.75MHz, 5MHz (representing 50MHz) out- generating and alignment equip- representing 51.75MHz where the side of television hours. You may ment, much less own such expen- Holme Moss vision signal should be even more fortunate to have sive artefacts.Ithas been sug- appear - and it did! Tweaking of locally one of the few holders of gested that both versions of the themixerinputcapacitor C8 50MHz transmitting permits who "Extrapolator"converterbe brought the 405 -line buzz up to a would be pleased to radiate a signal evaluated on external signals. This full throated roar. The IF inductor for you on which to align your "Ex- is a valid and practical procedure. havingbeeninitiallypeakedat trapolator". But other methods exist for those 5MHz on converter noise needed a If listening to your first amateur readers who are prepared to con- small adjustment of it's ferrite core signal on "Six" you feel inclined to struct their own cheap and cheerful to peakitat 6.75MHz, and up murmur to yourself: "Rarely, rarely home testing equipment. More of camethevideobuzztoeven comest thou spirit of delight" you this in a later article. greater strength (this on a horizon- canconsoleyourselfwiththe Reader should note this article tal dipole in the roof space at 80 thought that "spirits of delight" ex- is not intended to be in the realms miles from the station). ists somewhat more plenteously at of the latest "state-of-the-art" of The next operation was to set present on the higher frequency converter construction. Perhaps it the station receiver at 3.25MHz to band of 70MHz. I hope you feel will appal the cognoscenti. No mat- represent 48 .25 MHz, or somewhat that you should have facilities for ter:itwillappealtothe below the limit of the 50MHz band, listening on both bands. You can, constructor-domesticus.Thatis and up came the Channel 2 sound with the greatest of ease: go ahead my intentionat any rate.Inits signal. andbuildyourselftwo"Ex- development stages it was "made Eachconstructorwillhave trapolator" converters while you up as one went along", prompting available in this own district BBC are about it, one for "Four" and the the thought that it might have been video and sound transmissions in other for "Six". The two of them called "The Extemporizer" instead Television Band 1, on which to won't cost you much! of "The Extrapolator"! One hopes check that the "Extrapolator"is that you, too, will extract as much capable of receiving signals from Final -Final enjoyment from buildingit as the the outside world. writer did, and that you will gain More satisfactory, of course, is The foregoing discourse has quiet satisfaction from theloud to receive areal amateur signal said nothing about in-house test results it gives you.

HAM RADIO TODAY JULY 1984 53 At last,amagazine that gets to the coreof it.

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54 HAM RADIO TODAY JULY 1984 DO BuildinaBlocks FM circuitry is nearly always within system filter is the most important 25kHz channel spacing,itmust the context of VHF. All the follow- component in anysuccessful pass, with negligible phase error, a ing examples assume operation at NBFM transreceiver design. The band of frequencies 15kHz wide VHF frequencies(or transposing correct choice is far more signifi- derived from the expression2(f dev fmod ) while providing a minimum This month Frank Ogden, G4JST, delves into FM, in of 80dB of rejection for signals just particular FM IF strips. 25kHz away. This type of performance does from them in the case of discussion cant than, say, transmitter output not come cheap. Any useful NBFM about IF strips) and that the mode power,receiverde -emphasisor design requires a first crystal filter is narrow band FM. There are other even the 'front end' noise perfor- with at least 8 poles. A design us- frequencies and FM modes used in mance. The incorrect choice (or cir- ing a filter with less than this will amateur radio such as SSTV, RT- cuitdesignforan otherwise show an unacceptable disposition TY, wideband FM for microwave suitableunit)leadsdirectlyto to co -channel interference. With butthesearenotoftenen- receiver blocking, audio distortion decent units costing in the region countered; FM means narrow band low-level signal readability and one of £20 to £30, there isa great FM in 98 per cent of cases. or two other nasties.If you don't temptation to use those ubiquitous read any other part of this article, three legged 2 -pole filter units or, A Bit About FM make sure that you take in the next even worse, ceramic filters as in- bit. tended for FM tuners. The result There are two ways (three, ac- willnever be satisfactory, even Everyoneknows what FM tually but I don't propose to discuss stands for (I hope!) but what does it though the filter may be simply pro- DC PLLs here) of designing a prac- viding the 'roofing' function in the actually mean? You start off with a tical NBFM receiver system. The carrier at constant amplitude and double conversion scheme shown first, shown in Fig. 1, uses single in Fig. 2. It may appear that, since then waggle it about at a rate deter- conversion to 10.7MHz where the mined by the modulation frequen- the 15kHz bandwidth is provided signal isbothamplifiedand cy. The amount by which the car- bya ceramicfilteroperatingat detected. Chips such as Plessey 455kHz, then the requirements of rier frequency is altered gives the SL6650 canprovidetheentire amplitude of the modulation. Unlike the 10.7MHz filter before the 2nd IF/demod function for NBFM at this mixer are lessened. This is not the SSB or AM where the bandwidth is single frequency very effectively. limited to a precise value determin- case. The second mixer provided The second variety of design, on chips such as the MC3357 is of ed by the modulation frequency, as depicted in Fig. 2, is by far the the sidebands of an FM carrier are a lowleveltype. If a 'barn commonest and full of treacherous . much wider, naturally, but extend door.. as wide as' type filter is pitfalls.Thecircuitryhereuses used ahead of it then the contents out much further than the peak double conversion: from signal fre- deviation would suggest.Unlike of around 12 FM channels adjacent quencyto10.7MHz, and from AM, FM sidebands show a Gaus- to the wanted one are heterodyned 10.7MHz to 455kHz. Nearly all the down toitsimultaneously. The sian distribution at the sum of the amplification and detection is car- peak deviation and modulation fre- result is 'sproggies', intermod and ried out at this last low frequency. anunbelievable amountofco - quency.Inpractice,this means Either variation requires a top quali- channelinterference.Adjacent that it is very difficult to tell if that ty crystal filter which operates at box of grubby looking filtersof- signals of just 100 uV at the aerial 10.7MHz. Assumingthatthe can wipe this type of IF clean of fered for sale by a grubby looking hypothetical system is designed for traderata mud -up -to -the -ankles useable signal if the first filter is of rally is a bargain or not. 10.7 RF IN 0 MIXER CRYSTAL 10.7 IF QUADRATURE -0-0 AUDIO MHz FILTER AMPLIFIER DETECTOR Choosing A Filter

The delight of NBFM is that the LO circuitry is simple; any other mode TUNED TO is a nightmarebycomparison. 10.7MHz However looks are deceptive. The Fig.1Single conversion to 10.7 MHz (SL6650 series)

HAM RADIO TODAY JULY 1984 55 the cheap and cheerful type, no 10.7 10.7 2nd FILTER F AMPLIFIER QUADRATURE RFC-.MIXER CRYSTAL AF matter how good the 455kHz unit MHz FILTER MHz MIXER 455kHz 455kHz DETECTOR is. Terminating The Filter 9.9 10.245 MHz LO OSCILLATOR TUNED TO 455kHz Monolithiccrystalfiltersare Fig.2 Double conversion technique requires very high quality very fussy about what they are 10.7 MHz filter to avoid blocking of 2nd mixer with adjacent channel signals connected to. The high rejection and the closely defined bandwidth is produced by the critical coupling V+

of a number of independant crystal 100n

resonators, 'the poles'. The unit /7*77 MIXER will only function as a single con- 110 7MHz trolled bandwidth resonator if the .4°E-11 IF TRANSFORMER termination conditions, particularly 0 lion TO IF in respect of the resistance, are 100k I STRIP TO RF carefullycontrolled.They must AMP OUP J310 'see' a non reactive resistance as GAIN = 20dB specified by the manufacturer - 10n 220 typically in the range 1 to 4 kilohms in parallelwith a specified capacitiveloading-generally VALUE OF R TO SUIT FILTER around 20pF. Theseconditions Fig.3 Amplification with good termination

should prevail at each end. 220E Most IC IF strips require around +VCC 16V10 4k7 10k SQUELCH THRESHOLD 5to15microvoltsto achieve SETTING satisfactorynoiselimitedopera- 1k5 82k 0.1u tion. The output of the average 270p 6k8 front end using a couple of dual gate MOSFETs tends to be around 270n 8k2 two or three microvolts at noise 10.7MHz 10n 270k 100k IN FROM CRYSTAL limit. The difference between the 10n FILTER 15 14 13 10 AF 16 100k tworepresents a shortfallin OUT amplification when going straight from front end to IC via a filter. Fig. MC3357 IF IC 3 shows how to bridge the gain gap and provide a very predictable ter- 0.1u 10p r mination for both ends of the filter. 47k 47p 47k> > 2k2 Rd (SELECTED aI TO PROVIDE The IF transformer presents a very 2k2 TUNE TO I 1)?:r2;\15! 47p ... g I 455kHz BEST AUDIO. high impedance load to the drain of ( 22k.47k I T L _J the mixer MOSFET. Any resistance *vcc 0 placed across it becomes the 'real' resistance presented to the filter. In 455kHz FILTER use,thetuningslugofthe transformerisadjustedfor Fig.4 MC3357 application example minimum passband ripple. The in- putresistanceofthefollowing Fig.5 SL6650 series. The 6640 chip shown here FROM 0.01u incorporates an on -board audio amplifier JFET stage is determined entirely CRYSTAL 0-11.--11-1 FILTER by the gate resistor with a small I 0 VCCI6V) 0.1u value capacitor for reactive adjust- AUDIO 0.1u /7177 0/P ment. 15k RfL - /7)77 I make no apologies for going 10.22u 100u on at length about the qualities and SFE10.7MA requirements of the firstIF filter. 1

13 12 11 The goodness or otherwise of this /7)77 18 17 16 151 14 component and its installation sets

the standard for the finished piece f°330R SL6640 240k 120k of equipment. Even some of the

biggest names inamateur radio 3 8 equipment - I'm thinking of Icom 360k o.1. 47k gear in particular-tendto ._4_9 0.33u 0.1.7 47k 3.3n 240k 12k economise on this component for 470k /7177 180 FI, TO SUIT FILTER their FM boxes with a shortfall in Rf MAX = 1k 470k SQUELCH performanceas a result.The 0/P almostuniversallypoorperfor-

56 HAM RADIO TODAY JULY 1984 mance of CB set receivers (the characteristics(I have a personal 5. A difficult device to use because transmitters are almost universally hate for squelches with hysteresis allthe amplificationisdone at good) can be attributed directly to as found on the MC3357/9) and 10.7 MHz. Witharound100dB the filter factor. thepower supply(onlyuse a availableon a singlechip,the If you have fitted a decent filter CA3089 if you've got abuilt in layout requires extreme care.Itis and the recovered audio is distorted generator). my view that a groundplane PCB is at low signal strengths - and you I offer a few experiences of the mandatory. Also, the device needs can't get it any better with adjust- common types. to handled with great care as itis ment of the quadrature coil at the extremely sensitivetostatic. A end of the IF strip - then the ter- MC3357 Family badly earthed soldering iron will kill mination conditions of the filter are it stone dead. This circuit and all probably wrong.Itispossible to The typical circuit diagram s the Plessey radio chips are very verify this by setting up a weak car- shown in Fig. 4. The basic circuit fragile. This is because the small rier from a slowly tuneable signal works well but extra amplification geometry transistors which exhibit generator and then tune through after the first crystal filter is usually such excellent RF properties are as the receiver IF passband. If the ter- needed. Low power drain, around sensitive to static damage as the mination conditions are wrong, it is 4mA, is a real asset, which is why old fashioned MOS devices. possible to hear ripple as a series of this device (MC3357) has become Having said this, the Plessey peaks and troughs in the noise. the standard component for han- circuits are my choice for the ma- Remember thattheserepresent ditalkies manufactured the world jority of FM IF applications. The phase errors which lead directly to over. The logic level output from current requirements are minimal distortionofthemodulation pin 13 derived from the squelch cir- (about the same as the MC3357) envelope recovered from the detec- cuit is useful for switching off the there is a DC volume control, the tor. Thisis because NBFM isall entire power supply to the AF sec- squelch system uses a series of about phase. Addition of the JFET tion. A VN66AF driven from this detectorsthroughoutthechip circuitry as shown in Fig. 3 nearly pin can be used as the switch ele- which provides a logresponse always effects a dramatic improve- ment itself.I have never found any (SL6650 only). It provides the only mentinlow signal performance instability problem with this device on -chip S meter function which under these circumstances. largely because itis of the double gives readings that make sense If you have got the filter right conversionvariety.10.7MHz to with NBFM (think of all the other S and delivering enough IFsignal to 455 kHz; 10.245MHz oscillator on meters which read S9 with 4uV). whatever follows it, the choice of chip (crystal needed). There are operating disadvantages. what chip to use to provide the bulk The quadrature coil core requires of amplification and detectionis SL6650 Family critical adjustment and an outboard largely immaterial. It will depend on gain stage is mandatory. what you have to hand, the squelch Typical circuit is shown in Fig. CA3089 Family

.12V 40P 811-dv\%10., The original IC as used in suc- 47E TSOOnM cessive generations of FM tuners. 10uH The power consumption ofthis 10.7MH: INPUT FROMoI CRYSTAL chip is very high and the low im- 2k2 FILTER AUDIO pedance of the quadrature circuit CA3089 means that the coil is excessively Fig.6 The CA3089 damped when the chip is used for was the original FM IF 14 13 NBFM at 10.7MHz. It is possible to and demodulation chip II II lOn 10n Ok 22k increase the recovered audio by us-

O ing a 0.5uH coil tuned by around 10n 500k 270pF. The coupling inductance SQUELCH needs to be reduced to around O 47k 10 uHundertheseconditions. METER0 FSD 200 400nA Good qualities of the chip include an excellent log response on the S meter feed. An outboard IF stage is mandatory. AF DE EMPHASIS JILRal UIREDI

Rin Fig..7 The TBA120S TBA120S 0n FRg14.177T TERC.-11- was originally 14 OUADRATURE intended for COIL television. Very primitive chip. No mute or TBA120S'ISN76660.1 It works acceptably S meter function (it was intended at 455 KHz for a TV sound strip). Lacking in 3 gainat10.7MHzbutworks .0 VOLUME CONTROL reasonably effectively as the se-

INTERNAL CAPACITORS cond NBFM IF at 455 kHz. OF 4p FITTED FIT EXTERNAL CAPACITORS OF 33p FOR 455kHz OPERATION Next month - product detectors and SSB generators.

HAM RADIO TODAY JULY 1984 57 DMIN,10-n affSONAWSWAIMINgaralMINZOTradOMMeADMMAY.Wie'S'

, f. ;/. . , V4'4.4../;:t . "7, 4,47,,..AZ:e. e e//MAIL, ei/Yeee4 Ave:, e e /ASV/ ',A One problem, always present for the home constructor, metalworking I have done is an Abrafile. This tool is is that of how to achieve a reasonably professional finish possibly not well known to many home constructors and to the metalwork with the minimum of equipment. A few is extremely useful for cutting large or irregular holes in months ago, I mentioned a way of labelling front panels sheet metal. It is therefore ideal for making cutouts in to improve their appearance, and here are a few more front panels for which the correct size drill is not available ideas to help make the finished article more presentable. or the hole is not circular. Basically, an abrafile is a long One way in which the appearance of a piece of circular file about one sixteenth of an inch in diameter equipment can be greatly improved is to have a nicely and designed to fit into a standard hacksaw frame. If a painted case and front panel. This is most easily achieved hacksaw is already available, all that has to be bought is by purchasing one of the large selection of ready painted the abrafile and the small fitments for either end of the file. These are all readily available from hardware shops. To use an Abrafile, a hole large enough to take the file Get a professional finish and build a dummy should first be drilled. The file can then be fed through load with Ian Poole, G3 YWX the hole and attached to the hacksaw frame. The file should be kept under tension by tightening the nut at the end of the hacksaw by two turns (on most types of saw) after the slack has been taken up. This tension is cases available from most major component stockists! sufficient to prevent the file bending unduly and thus The main drawback with this (apart from the expense of causing the saw to wander, and not so much that the file course) is that the paintwork is very easily spoiled when snaps. It is then a simple matter to make the cutout the necessary drilling is being done. One trick I have follow an outline - which should have been marked found very successful in overcoming this is to cover all out previously, of course.

An Abrafile in place the vulnerable areas with masking tape, remembering Homebrew Dummy Loads that any exposed surfaces which are uncovered will be at risk. It is better to cover too much rather than too little! With the availability of many off -the -shelf ancillary One further advantage of this is that having covered the pieces of equipment, very often it is easy to forget that surfaces which are to be drilled, then it is possible to Fig. 2 Matrix construction draw on the masking tape and plan out the layout of the panel before drilling starts. If the project becomes delayed - as many of mine have done - and the masking tape remains on the panel for more than about two weeks, the job of removing the tape becomes progressively more difficult and, also, the surface will remain sticky after the tape has been removed. If this happens, as much of the tape as possible should be removed and the remainder cleaned off with a freon based solvent, which is often used in the aerosol cleaners available from many electronics shops. One tool which I have found very useful in the

58 HAM RADIO TODAY JULY 1984 some of them are easy to construct. Although the find that the cost of a suitable one cost nearly as much homebrewed equivalents may not look quite as as the transmitter! However, in fairness to these loads professional, they do perform perfectly satisfactorily. I they did possess an excellent frequency specification. found myself in this position some time ago when I Accordingly I decided to build a load from a bank of wanted to repair an HF sideband transmitter that I had discreet resistors. The main point to watch when bought cheaply in a partly working state. I looked constructing an RF load is to avoid introducing any through the advertisements for 'dummy loads' only to inductance. With this in mind, wire -wound resistors must be avoided at all costs because they become almost totally inductive at RF and hence totally useless for this purpose. Carbon or metal film resistors are bothequally suitable, and the load which I constructed actually used COAXIAL CABLE carbon resistors as they are available quite cheaply. This used 100 5K1 resistors to give a 51 ohm load - which is near enough to 50 ohms not to pose any problems! In order to reduce the overall inductance to a minimum, the leads should be kept as short as possible within the load itself. If only a few resistors are to be used, then the

RESISTORS arrangement shown in Fig. 1 can easily be used. If more resistors are to be used then the matrix style of layout shown in Fig. 2 will probably be more easily constructed and the leads kept as short as possible. One point to be Fig. 1 Circular born in mind is that there should be sufficient spacing construction between the resistors for ventilation; also, if the load is to be mounted in a case there should be adequate air flow through to avoid overheating. This type of approach is normally quite suitable for COAX OUTER ATTACHED HERE HF loads - in fact the unit which I built gave SWRs of TINNED COPPER WIRE INNER TO PASS BENT TO REQUIRED SHAPE THROUGH below 1.2:1 at 30MHz. However at VHF, the inductance (NB OTHER END of both the leads and the resistors becomes more SIMILAR EXCEPT COAX INNER significant giving rise to a substantial increase in reflected ATTACHED) power.

ADVERTISERS INDEX

HAM RADIO TODAY JULY 1984

Amcomm IFC South MidlandCommunications...34 Bi-pak 9 The C.O. Centre OBC B. N. R. & E.S 42 Western Electronics 31 CirKit Holdings 16,17 Wood & Douglas IFC Gamma Aerial Products IFC W.P.O.Communications 12 Quartslab Marketing 42

And don't forget, when calling an advertiser, mention Ham Radio Today, it helps them and us.

73's David Gadsden G4 NXV Advertisement Manager

HAM RADIO TODAY JULY 1984 59 ReadereADS

Vintage Radiogram GD 1050Cdisposalradio comms MagsFT101ZD andSP.901ex- Row, Bury St. Edmunds, IP28 inthreeuprightcabinets1968 to 1983 offers. Watnedspeaker good working order 8AX. walnut. 1). 5 band radio band -information for Book 2. Whatsand condition. Please phone spread tuning2).Turntableon frequencies from 36 MEegsJohnReading 598326ICOM 730 plus IC-PS20 brand with record storage 3). Bassto 4 GHz with so many scan-anytime. newboxed £520.Please reflexspeakercabinet.Ex-nersabout a lotmustbe phone G4NJC Crowthorne 77 change modern G.C. receiverknown. Ring for free book 1.Wanted PLL data books and4775 oroffers.Tel:NewcastleAnytime. 0473-85526. SSB CB frequency extension/ 2868291 modificationhandbooksICOM IC701Solidstate R600Generalcoverage(won't be used to pirate 10m).100W HF Rig,160 to10 Yaesu FT 290R with motorreceiver, good condition, twoReasonable price paid. Contactmetres completewithmat- matched preamp and mobileyears old. £200 (ono) G4GLTW. Jones, Henrhyd Isaf Farm,chingIC701 PS PSU and mount, NlCads, charger. Mint'Newhaven', Beveridge Lane,Colbren,Nr. Neath,WestICSM2 desk mike. Very little condition £250 ono. George,Bardonhill,Leics.,LE6 2TB.Glam. S. Wales, SA10 9PH. usefrom new only£500. 8KestrelDrive,Dalton. InTel: Coalville 35835. G4IVN QTHR. Great Yarmouth FurnessCumbria 0229 D-104 Silver Eagle, very good728194 63284 after 6 pm. Commercial Multi band dipoleconditon £35.00 or swop for £10. Icom Electret desk mikegood 444D. Also TM1000DATONGMultimodefilter NRD 515 Rx. Mint Condx 18£15. 2m 5/8 mag mount £10.Transmatch by Zetagi as newmodel FL2 together with MPU months old. £750 D. Menzies,AIWA HS -J02 Personal Stereo£25.00 (0952) 57670. AC Adaptor £45 the lot. Car- 11 GlebeRoad,Newtonas new £50. wanted good un- riage paid UK please telephone Mearns, Glasgow. modified WS No.62. KempYaesuFT 301D 6band(0534) 51 504 or write. Joualt 0793(Swindon)783462S/State CW Filt. Recently ser-"Chant Du Vent", Maufant, Tonna 9 elementcrossedafter 6pm. viced good condition £350.St.Saviour, Jersey. Channel YAGI 144MHz £25.00 ono. Tel: Letchworth 5023Islands.or would swop for IC260needsattentionYaesu FRG7000 General(G4UVQ). other radio equipment. £130.00.Pye pocketfonecoverage communications PFZUB 3 Ch's. £30.00. Extelreceiver 0 to 30 MHz digitalTONO 9000E.Communica-Cossor 1049 Tube only £6 set Teleprinter50/75 Baudsfrequency display very goodtionsTerminalUnit,Rtty,valves £5. Manual £3 KW204 £190.00. Tel: 025 481 3182condition £150. Tel: HamptonASCII, CW Graphics, light pen,manual £3. Six way heavy du- (01)941-0993 after5.30word processors, split screenty ceramic switch £4. various LinearAmplifier:Skipmasterpm. etc.£500. G3SSQ. QTHR.Cossor 1049 Bits, transformer HF-15 2-30 MHz. AM-FM- Phone St. Albans 51518. £3 each. 470 Ohms 25 watt SSB Pre-ampt 5-10in 20-15Reftec for sale. Perfect work- resistors50peach,new out:£60.00 ono.Tel:ingorder£200.PhoneSWAN 100 MX TransceiverG4GHB QTHR 061368 01-998-4713 Brighton 774381 after 6pm. 80m -10m SSB/CWR.I.T.9724. Good condition modern tran- Wanted - Crystal set for ex-Yaesu FT757GX HFsistor Rig£190 MBA/R0Yaesu 7700 receiver for sale 3 hibition. Must be genuine itemtransceiver plus YM 38 Mic,morse Rtty reader own displaymonths old £250. Mint condi- of the early 1920s. DetailsHardly used, £630. G4BUO.12 volts plug into audio outputtion. Runcorn 61439 please to: Stan, G3XON, 14Tonbridge (0732) 359742. receiver £120.00 VFO 7 MHz DagedenRoad,Shalford, £5.00.30P.A.,FerritesYaesu FR101 S.D19 FL101 Guildford, Surrey. GU48DD orWanted F.M. Board for Yaesu£4.00, 30 Rozel Court, Becktrans Yaesu 70-100 telephoneGuildford(0483) 36953. Victor Brand, G3JNB (centre) is the new President of Thames Valley ARTS

Exchange Realistic Pro 2001 Scanner Brand new. Program- mable with memories. Covers all VHS, UHF bands. For HF transceiver,tel:St.Albans 39333.

Heath Kit Short Wave receiver S.W.717 and general coverage. Phones and Manual good order. £20.

Wanted Digital readout of fre- quency for FRG 7. Telephone 0325 - 482983 Evenings. G6BCG QTHR

URGENT QST's from 1970 to 1983. Ring withPrice.For

60 HAM RADIO TODAY JULY 1984 monitorscope. YD -844A desk Also letters from Ex -RAF WWII mike. Ext. Speaker. Manual's W/ops(Blackpool,Compton for FR101 FL101 and YO -100 Bassett).FrankGlynn,41 £550 ono. TTC power SWR CrosswaysAvenue, East meter model C3005 free with Grinstead,Sussex.Tel: station. Write to N. Pugh, 5 (0342) 22967. BackLane,Nomansheath, Malpas, Cheshire SY14 8DR GEC BRT 400 communica- tionsreceiver II valve Oscilliscope model NI0-102 re- superheterodyne with anin- quires new fet £12. RF Signal tegral mains -operated power generatormodelN IG-102 supply unit using 3 valves (1 4 £10. VVM Model N may re- valvesin all).Frequency quire new meter £7. Tran- 150-33,000 Kc/s £80. Tel: sistor/Fetchecker£15.All 0672 40365 (evenings). Also with manuals and working. similar wartime set (not work- Part Completed S.S.T.V. REX ing). as per RAD COMM Feb -Mar 83 includes RS, CS PCBs. All POCKETPHONE on SU8 stand ICs less 3 £40. phone Ather- in charger good working order ton (0942) 891140. £30 ono. Also 4 element 2 metre quad jaybeam £ 1 5. Also Trio130V HFtransceiver. 2 brand new C.B. Rigs rotel 80M to 10m Inc. warc bands RVC220 in box with 11 month C.W. 250C filter. Mint Boxed guarantee from comet£ 1 6 £400 ono.Yeasu FT200 each. Would exchange HF QRP FP200 HiFi trans. V.G.C. box-metre Rigs plus 7dB attenuatorAs New YaesuF.T. 980TX.RX or WHY G4GMT Hud- ed black finish model £220(list£14.50)suits FTZ9ORtransceiver £900.00 alsodersfield, QTHR 0484 ono.Tel:Weymouth 0305etc., Mint, 6 months old, hard-YaesuFT.726 VHF UHF643124 W. York's. 786930 ly used £110 ono. Plus 70cmtransceiver with satellite con- wavemeter"Packer WM7"verter£750.00.TelephoneWood and Douglas 70 cms General CoveragereceiverFree!!Would swopforafter5 pm. 0277-823434.F.M.Transceiver,scanner, Century 21 complete coverage2MTX/RX orsomethingin-Brentwood, Essex. toneburst, S. Meter, 150KHz to 29.999MHz ex-teresting. Tel: 01-247 6097. microphone,P.T.T.change- cellentcondition£70 ono. Wanted Scope,Dualtrace.over speaker 1 2V 6AH Nicads Texas Instrument T199 com-Wood and Douglas 70 cmsModern,Compact,manual.2 channels fitted RB14,SU8 putercompletewithteachAtr. JxRx half watt output frequencycountertobuilt in aluminium box. Good yourself BASIC software Bookch36 vhf tv preamp filter £6t550 MHz.J.W.Johnson, 6working order £90 ono. Would ofprograms/gamesetc. 3ITC CIC4000 camera Iv compWaveney Grove,Clayton,exchange for S . S . B. months old.£85 ono.Tel:video out £40 2x SpectrumNewcastle,Staffs.(0782)transceiver for 70 cms. or H.F. Chester 311496. 48K £500s or software £165634780. transceiver.G4GMT QTHR WMLCV IC202S 70cm tx-Rx 0484-643124. FT101ZD, FM,FV101Z,RM.G4PLM.Tel:CoalvilleTandy TRS80 computer with SP101, £475. KW Vespa Mk812102. VDU, expansion interface andHF receiver realistic DX 160 I,£50. Microwave modules diskdrive£650.Marconi150KHz to 30MHz £80.00. converters, 2m, 4m, 70cm,Yaesu FRG 7700 as new mintTF851 Deviation Meter £50.Contact John G6KBS Baldock £15 each HRO coils,gen.condition 9 months old £240.AVO LF1 20 synthesised audio0462-892831. coverage £5 each. bandspreadFRV 770A 118 MHz -generator£50.Marconi £7 each. Tibbert, 32 Prescot1 50 MHz. FRT 7700 A.T.U.TF995 signal generator £150.Have 'AOR 245' 1-5 watt 2m Close, Mickleover, Derby. Tel:£70.or£290 completeWanted solid state RF signalhandheld(similartoIC2E), 515212. package.Hastings,Eastgenerator may PX. Telephone140-150 MHz (5kHz steps), Sussex 0424 51795. Mr. Finch 0274-563722. repeatershifts,Helicaland IC120 23 cm PLL FM telescopic whips, mobile and transceiver £399; Daiwa 2mWantedManualorcircuitRotator Hirschmann 250base chargers/PSUs. Swap for Lin. Amp. 1.5-4W i/p 50 +Wdiagramofphotostatofalmost new £25. Four elementICF 2001, CR2021, DX400 brand o/p£70. Eachunit HeathkitRG1 willpayex-quad £15. 6 amp ham poweretc.,PhilBridgesG6DLJ, new. Telephone Dougpenses etc. Tel:supply new condition £18. 40 703 (Southampton) G4/VK4AIZ Watford 092301-845-5904. amp power supply £9.Tel:891975. 662425. 01-540 3959. Sony 2001 receiver Wanted Mechanical bug key, FDK 700EX, 2M FM mobile,FM/AM/SSB digital push but-Help private tuition needed to70cm transvertor, 70cm linear 25W, V.G.C., £120. Jaybeamtontuningwithscanandpass RAE City Et Guilds examFor Sale ZX81(1K) £30 (or ex- 10XY/2M, £25. Would con-memory. Two sets NiCad bat-"B" licence. Prepared to paychangeabovecashadjust- siderexchangefor MMTteries plus charger plus AC1 22fortuitionplusexpenses.ment). Jim Hunt G3KQH NOT 432/144-R transverterandmainsunit.£75.PhonePleaseringSlough28304QTHR 0229 63397. Jaybeam MBM48/70CM or01-727 3199. after 8pm. Ask for Tony. similar.G6TK1QTHR.Tel: Wanted 2Mtr Handheld with Gravesend (0474) 59346. FRG7 Yaesu communicationsPractical wireless 115 copieschargeormobile.Exchange MMT 432/144R 70cmreceiverexcellentcondition.1960/1984.MorsekeysELIZO 350 SL Mac RO super 8 Transverter,1.6shift,10Also 2 metreconverter(small) £2 each. Electronic ig-sound camera supersound pro- wattsoutput,standardat-£135.00forboth.Ringnition, new £12.50 wanted,jector screen. Terry 01-622 tenuatorsuits10 watts 2Yateley 0252 875810. Ex -RAF forage cap; WWII RX.0809 London.

HAM RADIO TODAY JULY 1984 61 Free Readers' ADS Buy, sell or exchange your gear through our free service to readers

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6 GOLF CLUB FARNBOROUGH LANE, COMMUNICATIONS ISHERWOODS SALTFORD, 97 Osborne Rd. North Comp, ELECTRONICS BRISTOL Farnborough. Tel. 0252-518009 Hozler Street, Blackburn Open: 8 days 10-8 Tel. 0254-57616 Tel: 02217 2402 Yaesu, Icons. FDKs. Mosley aerials. Jaybeams. Open Tues Sat 9am 9pm G Whos Open: Mon -Fri 9-5, Sat 10-1 Close Mondays An Aladdin's Cave of Components

Radio Communications Amateur P M R Marine KENT LEICESTERSHIRE

ELLIOTT ELECTRONICS FOR TIN 111110 INTRUSIAIR 12 14 PENNYVVELL ROAD. BRISTOL. BSS OTJ THANET ELECTRONICS 95 Mortimer St, Herne Bay 26-28 BRAUNSTON GATE, Tel: (02273) 69464 LEICESTER. TEL: 553293 Open: Mon -Sat 9.00am to 5.30pm BUCKS Open Mon -Sat 9-5.30pm except Thursday 9-1 pm

Photo Acoustics Ltd. OF NEWPORT PAGNELL See theProfessionals W. MIDLANDS CM IC I'd SCARAB SYSTEMS FRIERF JAYBEAM, WELZ, DAIWA AMATEUR RADIO SOFTWARE DEWSBURYELECTRONICS V aNannluss 58 High St, Newport Pagnell Slolowo Milton Keynes, Bucks ICOM' STOCKISTS 176 Lower High St, STOURBRIDGE Tel: 0908 610625 29 Stafford Street, Gillingham Tel: (0384) 390063 0634-570441 Open: 9.30-5.15. Closed Thurs. & sun. ACCESS/BARCLAYCARD CH ESH I RE ADVERTISE DW ELECTRONICS G3X CF HEWARD'S HOME Amateur Radio Supplies STORES LTD. (Eat. 1963) 71 Victoria Rd, Widnes YOUR BUSINESS 822/4 KIngstanding Rd., Birmingham Tel: 051-420 2559 B44 9RT. Tel. 021-354 2083 Open Mon -sat 9-6 (closed Weds) Sun 9.30-12 G4RJM with 38 years in The Radio Trade We supply Yaesu, Trio, Kenwood, Tonna, Jaybeam, HERE Ham Equipment urgently wanted! Microwave Modules, Datongs etc Tel: 01-437 0699 Open: Mon -Sat 9-6

Technical NEW IDEA LTD SALES enquiries 133 Flaxley Road, G4SOV ESSEX G4STG Stechford, Birmingham StockistsofYaesu.Trio,Kenwood, AMTRONICS (TONBRIDGE) G4 SYZ Totsuko, Tonna Antennas, Bantex THE AMATEUR RADIO SPECIALISTS IN KENT Full servicing repairs on all makes of amateur radio. Open Mon -Sat, 10am-7pm, IT'S AMATEUR RADIO Sundays, 10am-1pm. I=1 ARROW Tel: 021-784 3129 VISA Electronics Ltd from AMTRON ICS 5 The Street, Hatfield, Peverel 8 Tollgate Buildings Nr. Chelmsford, Essex CM8 3YL Hadlow Road, Tonbridge, Kent Tel: 0245 381673/381626 Tel: (0732) 361850 Trio/Kenwood, Tonna, Welz, T.E.T FDK, AZDEN, YAESU, JAYBEAM, R. Withers Communications [wort('KD.K, Daiwa, Tono, Tasco FORTOP, DATONG, etc. 584 Hagley Road West. Oldbury, Warley B68 OBS Tel: 021-521 8201/2 Tel; 021-550 9324 Opening hours: Mon -Sat 9.30-5.30pm Late night Thursday 8pm HAMPSHIRE LANCASH I R E For all your communication requirements.

CALBRESCO LTD AMATEUR ELECTRONICS U.K./HOLDINGS AUTRONICS ^ Yeaesu. Tet, J -Beam, Frequency 142 Priory Road, Hall Green 258 Fratton Road Counters, Drae, Datong FT101 Portsmouth Experts. Repairs. 6JS6C, 12 BYTA Birmingham B28 OTB Tel: 021-474 4638 Tel. 0705 735003 6KD6, RFCler, Double Balanced Mixer, Warc Kit etc SAE. List 15 10.30am-6pm Tues-Fri. Closed Mon. Open 10.30am-6pm 6 days min. Junc. 31 M6. Free parking Sunday by appointment 43 Johnston Street Sat 10-5. Closed lunch 2-3 Blackburn B92 1 EF Surplus equipment/components & COMMUNICATIONS EQUIPMENT (0254) 59595 COMPONENTS, BOOKS, ACCESSORIES CLOSED THURSDAYS P.C.B assembly

HAM RADIO TODAY JULY 1984 63 it110111111161111)1

GREATER MANCHESTER SOMERSET YORKSHIRE

G6HKT G8 KVG 14 Cross Church St, Huddersfield Tel: AVCOMM LTD Open: 6 days 9-5.30. 0484 20774 25 Northload Street, Closed Weds. Thurs 9am-8pm G4MH Mini Beam Glastonbury 'Always a good selection o, new & 2nd hand equipment in stock' Open 7 days a week Tel: 0458-33145 Ham Radio CB & TV. 27 + 934 MG combined rig Computer software Aerial fitting service Open 9.30-5.30. Closed Wed Amateur Radio Shop 231 Chorley Road, Swinton, Manchester Tel: 061-793 1010 SUSSEX DISCOVER THE WORLD WITHAMATEUR RADK,FROM 4,4Sales 27, dok,dge St. eel seeds 1,2 3.G SOUTHDOWN LEEDS 452657 OPEN MON- SAT 40 TERMINUS RD (()PP. the PROFESSIONALS! Ea- 6pm NORFOLK PIPEID EASTBOURNE Railway SUPPLIES Tel: (0323)1 Stn.) TRIO ICON YAESU T LEDS AMATEUR PADIO MATE ORDERSE PVICE DE Pt OPEN MON -FRI Open: Mon -Sat 10-6 (Closed Tues) b0 GREEN ROAD ME ANWOOD L E EDS L S6 4, TEL 1011, a30a._5, SPANNER CITY CB CENTRE Stockists of: Yams% Trio, Tonna, FDK etc + aRmsi-f MADE LAR PRODUCTS secondhand and ex -Government equipment in *It Parkside Garage stock Thursford Grandstand Fakenham LA 83 SURREY Open 6 days Tel: Thursford 27 to 934 MHz TELECOM 9am-6pm 402 TRANSVERTER GUILDFORD COMMUNICATIONS 6 New Street, Barnsley 34 Aldershot Rd., Guildford South Yorkshire Open Mon -Fri 8am-6.30pm Tel (0226) 5031 Sat 8am-5.30pm Secondhand wanted Specialists in Yaesu, Icom D.P. HOBBS (Norwich) Ltd IICOMI and So -Kamp 13 St. Benedicts Street, Norwich \4f/ FDKEl ASDEN Tel: 615786 TOTSUKO Open Mon -Sat 9-5.30 Closed Thurs Stockists of: TYNE & WEAR WILTSHIRE YAESU, FDK, ICOM, JAYBEAM & Electronic Component Specialists APPromd FILYVVONICS PACE ELECTRON ICS Oath, ICON( 76 Victoria Road, Swindon Tel: (0793) 46807 Eastern Communications Yaesu equipment, BBC Computers + Software for the 129 Chillingham Rd, Newcastle-upon-Tyne Spectrum, Commodore 64 & Amtor. 31 Cattle Market Street Tel: 0632 761002 Open 9-5 6 days a week Open: Tues-Sat 10am-6pm NORWICH 4,1 We do everything for the BBC OPEN: 9.30- (0603)667189 5.30 Mon -Fri !mom] 9.30-5 Sat MAIL ORDER Please include my business details in the next available issue of Ham Radio Today NOTTINGHAM Only £17.50 per insertion, call us for series discounts on 01-437 0699 SP ELECTRONICS Business Name: 48 Limby Rd Huckhall, Nottingham Address: Tel: (0602) 640377 open Monday -Saturday 8.30-5.30 Tel. No: SCOTLAND Open Hrs:

JAYCEE ELECTRONICS JOHN GM3OPW 20 Woodside Way, Glenrothes, Fife KY7 5DF Contact (Office Use Only): Tel: 0592 756962 Open Tues- Sat 9-5. Quality secondhand equipment in stock. Full range of TRIO Post to:Emporium Guide, Ham Radio Today, goodies. Jaybeam - Microwave Modules- LAR. 1 Golden Square, London W1.

64 HAM RADIO TODAY JULY 1984 HAM RADIO TODAY CLASSIFIED Lineage: 01-437 0699 35p per word (minimum 15 words) EXT 332 Semi Display: (minimum 2 cms) Send your requirements to: £7.00 per single column centimetre Debbie Miller Ring for information on series bookings/discounts ASP Ltd., All advertisements in this section must be prepaid. 1 Golden Square, Advertisements are accepted subject to the terms and conditions printed on the advertisement rate card (available on request) London W1

EQUIPMENT RTTY

HIGH QUALITY CABLES

POPES H100 Super Low Loss . . . 50 ALPHA KEYS ohm ...80p per M(Post 5p/m) 10% off RTTY TERMINAL BOARDS. Precision engineered keys for the con- 50m ... 20% off 100m TTL output for computer £35 COMPUTER RTTY noisseur. Twin or Single paddle, and now POPES RG213U ... Same as UR67 Use your micro to transmit and receive the new "pump handle". One of the Very High quality., dia 50 ohm. 60p per incl. and for teleprinter £39 incl. RTTY lightest and smoothest movement ever. M(Post 5p/m) All boards come completely PL1 - PLL RTTY Terminal unit CAVITY WAVEMETERS POPES RG58C/U...5m dia High Quality wired and tested with FSK and 170Hz Shift Transmit & receive to Mil Spec 50 ohm. Same as UR76 Also handles ASCII TTL in/out For the UHF/VHF operator, one wave- 23p per M (post 3p/m) fordetailsto AFSK. S.A.E. Kit £13.50 Built £17.50 metertocover 144 mhz to over2500 mhz. UR57... Low Loss ',2" dia 75 ohm Coax... 2 Can measure rf as low as 50 mill watts 60p per m (post 5p/m) B. BrookesElectronics, FP1 - Two channel active filter & PSU with suitable meter. RG174U .. Miniature 50 ohm Coax ... LeicesterStreet, Norwich. for PL1. Requires 15/0/15v AC. COAXIAL RELAY KITS 25p M or UR95 @ same price (Post 2p/M) Tel: (0603) 24573. Kit £7.25 Built £10.75 The cavity block is pre machined to take UR70 . 75 ohm 6mm dia Coax ... 23p either BNC or N type sockets. Two types Per M (post 5p/m) Software for the DRAGON 32 300 Ohm SLOTTED RIBBON . . by RTTY send -receive program by of cavity available, Alum. type for HF, BOFA in Sweden'... 20p per M (post 3p/m) Brass for the higher frequency. Radio & RTTY Books G4BMK 75 OHM TWIN... 18p per M (post 2',p Split screen receive - Type ahead Send large SAE for more information to: per M) Confidential frequency list.Lists buffer. OSO review & many other Paul Sergent, G4ONF 14 s.wg. HARD DRAWN AERIAL WIRE 10,000 CW, aero, Coastal, fax, etc, fre- 6 Gurney Close, Costessey .. 20p per M (post 3p/m) features. Norwich NR5OHB STRONG PVC COVERED AERIAL quencies £8.25 + 60p P&P. Cassette £1 2.00 Tel: (0603) 747782 WIRE 6p per M (post 212p/m) Guide to RTTY Frequencies. Lists ROM Cartridge £21.00 N. PLU GS... GREENPAR 50 ohm Suite 4,500 commercial aero, UN, Coastal, UR67/RG213/H100 £2.40 ea Cnassis MORSE transceive program up to Sockets ... £1.80 ea. In line Sockets ... etc, frequencies £7.35 + 50p P&P. 150 wpm! £2.20 ea (Post 40p per Order) World Press Services Frequencies. Cassette £9.75 Cartridge £18.50 Send SAE for Full lists. News RTTY Services listing GMT, and Hardware interface also available. W.H. WESTLAKE country plus more £5.55 +50p P&P. 2 Clawton, Holsworthy, Devon + books P&P free. Please add postage to all orders - BRITISH TELECOM plug soc- INTERPRODUCT LTD U.K. 60p Overseas £1.50 kets & leads etc. Tel: C.W.AS HR1, Stanley, Perth PH1 400 Other hardware availablefor the (0274) 731532. Or visit our Tel: 073882-575 DRAGON 32 showroom oppositeOdsal For further details & fullpricelist Stadium, Bradford. please send LARGE S.A.E. to:- PNP COMMUNICATIONS TO BOOK 62 Lawes Avenue, Newhaven East Sussex BN9 9SB P. Simmons G3XUS THIS SPACE Tel: (0273) 51 Callers by appointment only please. BOOTH HOLDINGS Phone 01-437 0699 BATH, 6 GOLF CLUB LANE SALTFORD, BRISTOL BS18 3AA SOFTWARE EDUCATIONAL Tel: SALTFORD 2402 INCORPORATES HAM HIRE AND RENT -A -RIG G4B Mk Radio Software Dragon & Coco, CBM 64, Acorn, Atom, VIC20. RTTY Transceive. Split screen type ahead any Baud rate etc. ANY ALSO for Dragon: BUY, AERIALS MorseTransceive. Decodes& sends EQUIPMENT TO morse to 150wpm. Morse Tutor. Any speed, any spacing. SELL THEN FILL Includes a send practice facility. SELL, AERIAL WIRES & ACCESSORIES Amtor System. Available soon. IN THE COUPON Hard drawn copper wire 140ft 14swg Grosvenor Software (H. R.T.) £7.90 50 metres 16swg £6.90 10 22 Grosvenor Road, Seaford metres i2swg soft enamelled copper SWOP wire £3.50. 50 metres 1.4mm soft E. Sussex BN25 2BS enamelled copper wire £5.75. G5RV Tel: (0323) 893378 Type Aerials. '/2 size £12.00. Full size £13.95. 4mm Polypropylene Rope 50 metres £3.95. 4mm Nylon Guy Rope 50 metres £6.90. Ceramic Egg Insulators MORSE NOVICE TO EXPERT: Tel: Large50p.Small40p.Allitems 16/48kSpectrum.Phonetic ALL AMATEUR AND CB NEEDS postage paid S.M. TATHAM, 1, Orchard Way and characterdisplayfor ICOM, TRIO and YAESU, CYBERNET Fontwell, Arundel, West Sussex novice, random groups or per- 01-437 0699 HARBARD and UNIDEN. TAGRA,G.WHIP, HOXIN, MICRODOT sonal text for more able. Vari- RTTY. SWR & power meters. able speed. Price £4.95. Also Receivers & linears. Plus all other C90 Cassettes (exchangeable) accessories. COURSES with 5-10 morse exercises. Aerial Fitting Service State speed. £2.95. Both com- 231 Chorley Rd., Swinton, piled by professional operator. CBM 64, VIC 20. Spectrum, ZX81.16K COURSES - RADIO AMATEURS MORSE TUTOR Absolute beginner to Greater Manchester. MMX, 30 Waterside View, Leys- any test standard Teaches in easy Tel: 061-793-1010 EXAMINATIONCity & Guilds. down, Sheerness ME12 4 PW. stages.Letters,figures,words,plain Pass this important examination language. You won't find a better program and obtain your licence, with any 0TH LOCATOR Worldwide. Locator or RRC Home Study Course.For lat & long. Distance. beam heading, VHF contest points and total. RALLYS details of this and other courses COMPONENTS RAE MATHS TUTOR All you need to (GCE,professionalexamination, become perfect. VIC 20 needs expansion. etc.) write or phone - THE RAPID All programs are menu -driven easy to IDIOTS will miss the RESULTS COLLEGE, Dept. JN2. AERIAL AMPLIFIERS improve use and come with full instructions. Tuition House, London SW19 4DS. television reception. Only £6 each, inc. p&p 1st Class by McMichael Home Counties weak return. Rally, Slough. 11am 22nd July. Tel: 01-947 7272 (9am-5pm) or Price £6.70. S.A.E. for leaflets. technical software 1/2hr from London on M4 (J N6). use our 24 hr Recordacall Service: ElectronicMailorder, Rams - Fron, Cesarea, Caernarfon LL54 7 RF Talk -in S22, SU8. 01-946 1102 quoting Dept. JN2. bottom, Lancashire, BLO 9AGH. Tel: 0286 881886

65 HAM RADIO TODAY JULY 1984 CARDS, STICKERS CARDS, STICKERS SURVEILLANCE BOOKS & BADGES & BADGES DEVICES AIRCRAFT COMMUNICA- TIONS HANDBOOK (Europe) QUALITY RUBBER STAMPS, including UK spot MF, HF, VHF, club emblems from 85p each QUALITY UHF frequencies, Military, Civil, completely mounted address PersonalizedQSL's cards any MICRO -MINI TRANSMITTERS ATC, Airports, Long Range Sta- stamps £2.75. Free catalogue: quantity from £1 1.00 tions. Beacons, Callsigns, Co - Jones (HRI) St Ivy, North Rd.. - as supplied ex -stock,returnpost Nutley Press, 11 Barons Way delivery, no special equipment required, Ordinates, Broadcasttimes Queenborough, Kent. (0795). Woodhatch, Reigate. Surrey built, tested, with instructions. etc. £6.95p. inc P/P. PLH Elec- 665789. Tel: Redhill 71023 CT1OH, 4 mile range, broadcast quality speech pick-up £13.98. tronics. 70 Vallis Road, Frome, CT10M, prof grade. extra high power, Somerset BA11 3EJ. tunable freq 70-120MHz variable mic- HIGH CLASS QSL Cards. Fast rophone sensitivity. £19.48. THIS SPACE delivery. S.A.E. for samples and CT1OMB, as above + unique dual mic- MORSE SOFTWARE rophones to elminate echoes, noise etc COULD BE YOURS prices to: J.S. Coates, 57 Worrall £21.40. Street,Morley, Leeds LS27 All specialised requirements catered for. 0 PJ. EVEN RADIO STATIONS -+ telephone PHONE DEBBIE line recorded device. Please enquire: 061.905 1040. RADIO MORSE ON 01-437 0699 S.A.T. ELECTRONICS QSL cards at competitive rates. 164 Washway Rd Sale, Cheshire M33 1 RH READING FOR DETAILS SAE samples. Sigmaprint PROGRAM FOR ZX81 (HRT), 62 Newark Lane, Ripley, Surrey. Unexpandedmemory.Prints translated morse code on screen LISTENER & QSL CARDS. FOR SALE with spaced scroll action - easy Quality printing on coloured & toread.Variable speed. £7. white Glass Card at competi- Spectrum version £8. tive prices. S.A.E. for samples: S.M. Tatham, "Woodside", ADVERTISE Pinehurst Data Studios Orchard Way. Fontwell, Arun- YOUR CARDS 2 METER SSB Transceivers 69 Pinehurst Park, West Moors del, W. Sussex. from £138. Full range includ- Wimborne. Dorset BH22 OBP HERE ing ICOM, TRIO, YAESU, ASDEN, ETC. Credit facilities. Guilford CB. 0483 574434 RUBBER STAMPS. Per- sonaliseyour QSL,Special CLUBS designs no problems. Discount for quantity. Two day service. AMATEUR EQUIPMENT S.A.E. for catalogue. Ben Nevis, PUT YOUR bought, sold, exchanged. Tel: RADIO CAROLINE SOUVEN- 42-44 Princes Rd., IRS. For sit send SAE. For all Hull. 04024/55733; or send S.A.E. offshore radio news. Subscribe (0482) 48134. for current list. G3RCQ 65 Cecil to our mangazine. Send £3 BUSINESS Avenue, Hornchurch, Essex. Subscription to Caroline Move- ment. Dept A. BCM-BFRM, Lon- don WC1 N 3XX. PERSONALISED QSLs, ON THE CERAMIC TAG STRIP (Jack- Amateur, or CB, 1000 £13.75. son) 15 Tags 10 for £1. 6 Way S.A.S.E. for samples. H. Hope, Stand off terminals 10 for 75p. 89 Derwent Street, Blackhill, MAP USE List 1 5p + S.A.E. Durrant Com- ALARMS Consett, DH8 8LT. ponents. 9 St Marys St. "Ham Radio Shrewsbury. BURGLAR ALARM EQUIP- CASWELL PRESS - estab. MENT. Please visit our 2,000 1974. Quality Q.S.L. cards to sq ft showrooms or write or your own design. Today" AMATEUR RADIO EQUIP- phone for your free catalogue. S.A.E.,21 MENT bought, sold, exchanged. C.W.AS. Ltd. 100 Rooley Holmethorpe Ave, Redhill, Telephone G4OWY Weymouth Avenue, Bradford BD61 DB. Surrey. Tel: Redhill 71023. 0305 786930. Telephone 0274 731532. T HAM RADIO TODAY CLASSIFIED ADVERTISEMENT- ORDERFORM

Advertise nationally in these columns to over 100.000 readers for only 35p per word (minimum charge 15 words). Simply print your message in the coupon and send with your cheque or postal order made payable to Argus Secialist Publications Ltd to: CLASSIFIED DEPT., HAM RADIO TODAY 1 Golden Square, London W1 R 3AB. Tel: 01-437 0699 Please indicate classification required. Name Address

Tel. No.(Day)

Please place my advert in Ham Radio Today for months. Please indicate number of insertions required. Or Debit my Access/Barclaycard (Delete as necessary) - 66 HAM RADIO TODAY JULY 1984 HAM RADIO TODAY MORSE COURSE The most effective route yet to your Class A amateur licence! Professionally produced for HAM RADIO TODAY by Shirley Hesketh G4HES and Ron Ray G3NCL, this ad- vanced interactive learning system makes use ofthe stereo cassette format to pro- vide tuition to the 12wpm test standard. With its carefully designed structure, we think that the HRT MORSE COURSEis more effective than either morse classes or electronic morse generators. Based on TWO C-60 casset- tes,it offers the controlled prompting so necessary for the initial stages of morse tuition, followed by careful- ly paced test material to br- ing the student up to speed. Full tuition notes are provid- ed with the cassettes. Toreceiveyour MORSE COURSE simply fill in the coupon below and return it to: 'HRT MORSE COURSE', ArgusSpecialistPublica- tions Ltd,No1 Golden Square London W1R 3AB II= NW NM =11 =5 =5 NW 5= 1=1 5= =I =51 IMI MB 1=1 11= 1=1 =5 I= =M MN =8 5151 51. i=I NW I= =I II= =I MIS 1M NW II= I=1 I= =5 =II =11 Please send me the 'HRT Morse Course' at £11.45 all inclusive of P & P and VAT. I enclose cheque/ PO for £ (payable to ASP Ltd) OR Debit my Access/ Barclaycard (delete as necessary)

Please use BLOCK CAPITALS Name (Mr/ Mrs/ Miss) Address Postcode Signature Date Please allow 21 days for delivery Mon10 Merton -Friday Park, 9.30-6.00 Parade, Kingston Road, (Near Nelson Hospital) London SW19 Sat. 9.30-4.30 LONDON'S NEWEST AND BRIGHTEST Telephone: 01-543 51 50/421 2 THE C.O.CONFIDENTIAL IL/ . CENTRE Credit available for FREQUENCYLATESTCOMING RINGLIST. EDITION NOW SOON FOR DETAILS °. 2mts or 70cmsorder E10 mail inc $SPECIALp&p HB9 CV's SHEPHERDAsk forFINANCEB+A written Licence details. holders through ANDOUR PRICES CRUMBLING WALL £11.50£18.507MHz1.1inctraps Baluns includingC. W.telegraphyGet THE 2 asimulated G4HXZ EASY Key morse GPOWAY HK706/7 teststape and a hi -mound London's £8.5070cms2mtsMail or order. inc The pair £19.50 inc p&p ANTENNAS NEW LINESTHE CLUNKER stockist.only inc p&p. IN STOCK NOW Full or half size G5 RV G4HXZAt last!stable, a heavy a uniquewith solid brass design brass name on handmade marbleplate, impossible or morse wooden key to base, fromdescribe the fully here. Ring now for more details. THE C.O. PHASER Just plug in your aerialTune and to T.V.channel23CMS 36 approx CONVERTERSFOR ONLY £29.95 onlyAccess £11 .50 inc p&p Phasing problems on 2+70 solved for only £10.50 inc p&p. If your thinking about and your away. Part ex. COMMODORE VIC 20 THEBARGAIN MONTH OF tionaspectamateurlistening then of radio popradiocommunica- inor and short have wave a or in fact any SHORTWAVE LISTENERS CORNERThe ultimate receiver. Collins R390/A.£350. no offer 0.2-30mhz only £38.00 Global A.T.U. A.T. 1000 °- considered. -2welcome. .\Anything extend for one month only. Boxed £70.00 new. tochat nearhelp. and certainty a cup of we'll tea. be It's able a LIGHTWEIGHT YAESU HEADPHONES YH77 £11.50