INDEX AND ACKNOWLEDGEMENTS ISSUE No.13 MARCH 1985 Page 1................Index Page 2................News & Views Page 3................News & Views Page 4................Letters Page 5................Tech-eds Notes Page 6................Tech-eds Notes Page 7................SSTV Page 8................First Byte Page 9................First Byte Page 9................For Sale & Wanted Page 10...............Technical Index Page 10...............Library Page 11...............Diary of Events Page 11...............Club Equipment Page 12...............Membership List Page 13...............Membership Form Editor................Dave Chislett G4XDW Technical Editor......Dave Lomas G4XOW (New) Printer...............Dave Ayres G6GBC Computer Editor.......Mike Brown G4RAA (New) **************************************************************** B.B.R.C. COMMITTEE Chairman..............Dave Bentley G6LKZ Secretary.............Paul Robinson G6DVC Treasurer.............Lynas Newton G6LYN Member................Mike Brown G4RAA Member................Martin Heaver G4WSW Library...............Dave Bentley G6LKZ Club Equipment........Dave Bentley G6LKZ **************************************************************** New Club Rooms...........Haymill Community Centre 112 Burnham Lane Slough. SL1 6LZ NEWS & VIEWS Questionaire 1........There was a good response to the questionaire on Beechlog. Thankyou to those who gave them back to me. It seems that most people are quite happy with the magazine and most felt that little change was necesssary, if you mentioned a change in your form we will try to incorperate those changes in the forth coming issues. On the subject of change see elseware for changes in the editors etc. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Just recently some members of the club have bought Compact Disc Players. Apart from the goods sounds to come from these Lasers, I was particularly interested to find a low level of RF radiation from the model I bought. Contrast that with the computer this magazine is being compiled on. In the workshop recently we had a Sinclair Spectrum made for the Spanish market when opened it contained a screening paint and when closed a low level of RF radiation. Once more we find that we are the poor relations of the world with high levels of RF coming from everything we buy. Elseware in this issue are details of a paint which could help with not just computers but with all those other things that contain the dreaded CHIP. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ In this issue we say goodbye to Gerry G8VNA who retired as Tech-ed. Gerry and Carroll have decided not to rejoin the club this year due to pressures of work and the extra distance to the club house. I would like to say thankyou to both of them, both contributed so much to the magazine in the early issues, later Gerry became the Tech-ed not an easy job. I think you will all join me when I say I hope they will return to the club in the future. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ This issue sees Dave G4XOW taking over from Gerry as Tech-ed please direct all technical articles to him. The final date for all items for inclusion in the June issue is May 10th. Please, if you can, give items to the editors as soon as possible this does help reduce the load in the weeks up to publication. A new page appears this issue suggested by Mike G4RAA on computers in radio. Mike will be editing this page so items of interest on computing to him. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ NEWS & VIEWS Hot on the trail of my tale of G4VRK and his RTTY mailbox I recieved a printout of yet another mailbox heard at various places up and down the 2mtr band. This station G8ATS seems not to have heeded the words of the RSGB and BARTG and is running contrary to his licence. What I think is more worrying is that others are planned if not already up and running. What do you all think about these Mailboxes please let me no and I will print some of your thoughts next issue. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Taking of mailboxes I received a letter from a club member see next page for details. Mike got onto the Prestel computer within minutes of reading that I had a mailbox number I was at the time accessing other pages and as I was about to sign off I was told of a message. Eileen had delivered the magazine to Mike that evening. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ As mentioned previously I have found out more about the paint shown on 'Tomorrows World' for screening computers. The paint is called MS-485 RFI Conductive Coating (Black), manufactured by Miller-Stephenson Chemical Co, Inc. Quoted attenuation for a coating is 105db at 150Khz to 44db at 1000Mhz. Worse fiqure appears at about 100Mhz with only 21db attenuation. In this country the cans can be obtained from: D.Frazer and Company 129 Kylepark Drive Uddingston Scotland. Price is about #5.50 a can with a can and a half suitable for doing a TRS-80 computer. I have a leaflet and test report on the product so if anyone is interested please contact me. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Too late for inclusion in the last issue may I say congradulations to Greame and Gale on the birth of their daughter Emma Jane. Born on the 9th December. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ LETTERS TO THE EDITOR Dear Editor, I should like to express my disgust at remarks made by B.B.R.C. members and committee members during the Extraordinary General Meeting held in November last. It has always been my belief that Amateur Radio provides the opportunity to bring together peoples around the world in a common interest. Hence the delight and interest shown in making difficult contacts in obscure tangents of the globe, not to mention floating around in space. Yet, at the EGM several people openly expressed extreme racist views, indicating in no uncertain terms that anyone not white would not be made welcome. Well I suppose Mr. Ghandi wouldn't want to come anyway. I am quite aware that we all may hold whatever views we like personally, in our society where we are allowed freedom of speech. However, in a club which purports to be open to anyone with a genuine interest in Amateur Radio, the remarks passed openly at the EGM were offensive. I don't imagine that any of these people can bring themselves to do much but snigger at this letter, but I trust that I will have no further cause to be offended by any comments made in public by my fellow amateurs. Yours Eileen Chislett G6EIL TECH-EDs NOTES "You've got a BBC Computer and Word Processing facilities, haven't you ", asks Dave (G4XDW). "YES" I say. "How would you like to be our new Technical Editor?". (not a lot, seemed a good answer). But seriously here we are and firstly I am sure I will be speaking for all of the club in thanking Gerry (G8VNA) for all the work he has done as previous Tech-Ed. In order to avoid repetition, I have made an index of all technical articles to date; this will be included in the magazine. If anyone wants a copy of any of these, I am sure the Editor will oblige. My latest venture has been to construct a simple SSTV adaptor for the home computer. Thanks to Dave (G4XDW) for typing in a program from an article and getting it working! I managed to get what is best described as a J.L.B quality picture. Some way to what Tony (G4LQD) has been achieving. Apparently, the pictures on tape that I was using are frame sequential colour so with some off-air B/W signals, hopefully, Ann (XYL) will think this #1000+ worth of gear is justified. Some of the you members will be aware of my local interference on the H.F Bands. I thought it would be worth reporting the events in case any of you face a similar problem. On finally getting the G4 (after a struggle with the dreaded morse best forgotten about), I purchased a DNT CB rig and modified it to 10 metres. With no aerials up at this time I put it in the car along with a G-Whip antenna. On turning on I could hardly believe the result, S6 on every other channel with this horrible droning noise. Driving down the road it faded away so I started using 10 meters mobile making sure the contact was over before reaching home. The other phenomenon I noticed was the source was not too stable and so one could not simply avoid certain channels. After eliminating everything in the house and checking at 3 a.m. one morning, I concluded it was not local domestic equipment. Eventually, I decided the factory across the road could be the source. TECH-EDS NOTES Now what was this large diameter cable (the size of coax I wish my down lead was), that B.T. had installed when the activity changed from fixing fork-lift trucks to an export business! I managed to catch a director one day and taking the rig (nicads strapped to the case) up to their office, there was about half a dozen phones and a large steel cased super microprocessor battery backed up system. Flicking around the channels it was hard to get the meter off the end stop. Anyway he agreed to contact B.T. and I eventually decided to fill in a form obtained from the Post Office to the D.T.I. interference investigatory division. Unfortunately, this is only intended for reporting broadcast band interference, but it is all that is available. Unfortunately (again), it was sent to the Reading Division, which was about to close, so apart from a telephone call later from an engineer who had given up trying to locate our house, we heard no more until the Oxford Division took it up. I was told on the phone that they normally have to charge for anything other than interference to broadcast bands, but he would take a quick look. The result was that the installation is known to cause this problem and B.T. would be advised to fit filters to the lines, a procedure only taken when a complaint is made. Well the equipment is in a screened box, but like my transceiver with a long wire attached, it radiates nicely. This was all several months ago, has anything been done? 73 ' Dave G4XOW P.S. Question----- How far will 27 mhz go under water? Answer------- A colleague at work (C.Gross, who organises radio control demo at McMichael Rally) runs a model submarine which he tested in an 18 foot deep tank; it was controllable at the bottom. (Editor's comment?) However, it is only controllable to a depth of about 6 inches in sea water! Dave G4XOW SLOW SCAN TELEVISION As many of you are aware, I have for the past year or so been active using SSTV, mainly on the 20 metre band, using my computer, a Tandy Colour System, together with a simple interface which separates the sync from the incoming video and feeds them into the computer via one of the joy-stick and the RS232 ports. This system, together with some very complex 6809 machine code programmes, has been very effective. Recently I was able to acquire a purpose-built converter - the SC-1 - made by Volkes Wraase Electronics in Germany (DL2RZ). This is a "state of the art" converter giving 64 grey levels and can also receive and transmit FAX. For black and white pictures it can receive the following: 8 second (128 lines by 128 pixels) and store 6 pictures 16 second (256 lines by 128 pixels) and store 4 pictures 32 second (256 lines by 256 oixels) and store 2 pictures The quality of the received 32 second picture does not differ much from the definition on your normal TV set. For colour pictures, it can receive and transmit 2 different systems. 1) Frame sequential - red,green, and blue pictures are transmitted as 3 individual SSTV frames and then combined. 2) Line sequential - here, red, green, and blue lines are transmitted alternately, the memory is switched automatically and the picture appears on the screen as it is being transmitted. The sequence lasts 24 seconds (3x8). The converter can also receive FAX (both AM and FM) at 280/120/60 lines per minute and will automatically start and stop on the appropriate phasing signal. I hope to be able to give you more experiences of this unit in a later issue. Tony, G4LQD (P.S. Dave G4XDW has done it at last) FIRST BYTE This is the first of a regular column on computing and radio. I hope that I will find topics that interest not only computer owners, but everyone else too. As always though, it is difficult working in a vacuum. So, if you hate the column or know of something worth including, please let either myself (Mike), or the editor, know. I took delivery of a new Shinwa CTI CPA-80 dot-matrix printer just before Christmas, and I'm very happy with it. It has 9 different typefaces and sizes of print, 4 different 'weights' of type, user definable characters, proportional spacing, high res. graphics and a 4K print buffer. And you thought you were confused! Just to add to the chaos, I've been given a copy of a telesoftware program which can print in a 'handwritten' typeface. Hopefully things are going to get even more exciting on the radio/computing front in the near future. Of course, many people are using computers to generate RTTY. (Including me, since last week.) Whilst this has the advantage of being a well known standard, there are other, more efficient methods of sending text (or data) over an R.F. path. One way that's very popular, particularly in the States, is Amtor. I'm sure most of you know that this is a form of RTTY. The baud rate is faster than standard RTTY, at 100 baud and, even more importantly it is error correcting. It shares with RTTY one disadvantage, though. In both modes there is a transmitter on the air at all times. This means that, when sending an over, your transmitter is radiating full power all the time. Obviously transmitters designed for SSB need to be severely derated if asked to radiate a continuous carrier. Also, of course, the frequency can only be used by one QSO at a time. There are many specialised terminal units available which will handle Amtor, RTTY and ASCII. (The latter being data sent using RTTY tones but ASCII rather than Murray code.) These black boxes are rather expensive, when you consider that you also require a computer and a rig! Naughty but nice? Fortunately there is more than one way to skin the proverbial cat. Software can often provide the solution to a hardware problem. There are, for instance, a few RTTY programs which need no terminal unit at all. Likewise there are programs to run Amtor with only a normal terminal unit, like the ubiquitous ST5. Hopefully there will be one available for the BBC B shortly. (Three guesses which computer I own.) BIT TWO The Real Thing however, is Packet Radio. Gerry (G8VNA) and I have conducted some very interesting experiments with a BBC B program written by two hams from Cambridge University Computer Laboratory. The program is a bit rough and ready (like it doesn't really work as supplied!) but has some very interesting features. It does not need any sort of terminal unit, just a lead going from the computer cassette socket to the rig. Audio from the computer goes to the rig mic socket, and from the rig speaker socket to the computer. The cassette control relay is used for RX/TX switching. Both of us were surprised how well such a simple system worked. Signals were decodable until there was quite a lot of noise on the audio, corresponding to about S 0.5 on my rig! The major advantage of the packet system though is that it is error detecting. It works like this......Station 1 transmits a packet of data addressed to station 2. If station 2 receives the packet then it transmits an acknowledgement back to station 1, which will then send the next packet. If, however, station 2 does not receive the packet then no acknowledgement is sent. Station 1 then automatically re-sends the last packet. It will do this up to ten times before giving up in disgust! That's it for now, I'll keep you posted about further leaps in technology (Quantum, or otherwise!). Mike (G4RAA) +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ FOR SALE & WANTED Bits and pieces to go in this slot!!!!!!!!!! TECHNICAL ARTICLES INDEX MAR 1982 A 24 Hour Clock (using junk sale module) Mobile Boom Microphone SEPT 1982 Base Station Microphone (using SL622 or SL1622) DEC 1982 Making Printed Circuit Boards MAR 1983 6 Amp 12 Volt Power Supply JUNE 1983 Transistor Tester SEPT 1983 Testing Transistors with a Multimeter DEC 1983 T.V Circuits - UHF Diplexer & 600Mhz (radar) Filter Simple 2 meter Dipole (using 300 ohm ribbon cable) Tone Burst Generator (using CMOS 4060 device) MAR 1984 Converting ICOM 1050 to 10 meters Tapping a Banana-Tree to receive T.V signals (not that useful in U.K!) JUNE 1984 A Wavemeter for 144 Mhz. SEPT 1984 Dry-Fit Battery Charger DEC 1984 Noise Bridge Circuit MAR 1985 Technical Index ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ CLUB LIBRARY HF Antennas for all Locations Moxon 1981 Call Book RSGB 1984 Call Book RSGB Radio communications Handbook RSGB R.S Components Cataloque Confidential Frequency List +Suppliment +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ DIARY OF EVENTS 4th Feb..................G3CWI Slide Show Antarctic 18th Feb.................G3JKV Auroras 4th March................A.G.M. 18th March...............G3RZP ATUs & SWR 23rd March...............RSGB VHF convention Sandown Park (Saturday) 1st April................FoxHunt (Please note usual start Upton Court Car Park) 13/14th April............RSGB National Convention Birmingham 15th April...............G8DPH A.T.V. Demonstration 6th May..................G4CGS H.F. propagation 18/19th May..............Spring Picnic (Sat/Sunday) 20th May.................G4END Slow scan TV & colour 3rd June.................G3CWI Slide show ? 17th June................G4PHS R.F. filter design 30thJune................LongleatMobileRally 21st July................McMichael ARS Mobile Rally ***************************************************************** Further evenings planned but not confirmed.......... Moon-bounce 6Mtr operation PMR equipment ***************************************************************** CLUB EQUIPMENT 1. 25ft Telescopic Mast/base/guys & pegs (G4XGD) 2. J-Beam 2mtr+70cms Beam/cables (G4XGD) 3. 4x23 ele JVL 23cms Beams (G4XDW) 4. Tent+Awning pegs (G4XOW) 5. G5RV HF Aerial/cable (G4XGD) 6. AM. HF Tranceiver 'valves req' (Club Rm) MEMBERSHIP LIST 001 Eileen Chislett G6EIL Sl.21896 002 Dave Chislett (Editor) G4XDW Sl.21896 003 Tony Alderman G4LQD Fc.3286 004 David Ayres (Printer) G6GBC Md.28108 006 Paul Shayler G6TSF Sl.41396 007 Bill Perkins SWL Sl.32171 008 Lynas Newton (Treasurer) G6LYN Bn.66759 009 Mike Brown (Committee) G4RAA Bn.4262 011 Dave Lomas (Tech. Ed.) G4XOW Lt.Grn.2847 012 Ann Lomas SWL Lt.Grn.2847 021 Peter Harman G4XGD Sl.28826 027 Graeme Platts G4XOF Sl.78495 030 Richard Ashberry G6RTM Sl.46012 031 Ted Swaby G4XOE Sl.75099 033 Dave Hemmins G6DRP Bn.64436 034 John Williamson G4XJN Sl.24008 038 Paul Robinson (Secretary) G6DVC Rslp.72125 043 Bruce Gilson G4WVX Bn.64415 047 Peter Melling SWL** Sl.29025 048 Mike Gathergood G4KFK 0895 834167 049 B. Mockett G1DSI ******** 050 T.Kay G6LRZ Bn.4255 ******************************************************************* Please note if your details are not correct please use the form on the back of the magazine and hand to a committee member. This will help us to keep the records up to date. ******************************************************************* THE BURNHAM BEECHES RADIO CLUB G3WIR G6WIR The Burnham Beeches Radio Club, affiliated to the Radio Society of Great Britain, serves the Slough/Windsor area, although it got its name from its original meeting place - or that vicinity. We meet twice a month, and our activities cover a wide range of topics related to radio communications, such as lectures, demonstrations, and club operating nights; there is also a keen interest in home computing among our members. We welcome members of any age and sex, who have an interest in Amateur Radio, whether they be licenced amateurs or 'Short Wave Listeners'. Meetings: 1st & 3rd Mondays of each Month at 8.00pm Haymill Community Centre 112 Burnham Lane Slough. SL1 6LZ Secretary: Paul Robinson G6DVC. Telephone. Ruslp72125. ******************************************************************* MEMBERSHIP DATA FILE NAME:.................................... CALLSIGN:................ ADDRESS:................................. DATE:.................... ................................. TELEPHONE:............... ................................. POSTCODE:................ BANDS WORKED: HF( ) VHF( ) UHF( ) MODES USED: CW [ ] SSB [ ] FM [ ] RTTY [ ] ATV [ ] MAIN INTERESTS: (Building, contests, ATV, RTTY etc;) ................................................................... ................................................................... ................................................................... SUGGESTIONS FOR CLUB ACTIVITIES: ................................................................... ................................................................... ................................................................... COMPUTER INTEREST:...................... MODEL:................... [All details held in confidence by the committee] *******************************************************************