SRW Communications Ltd.
was set up in 1987 by Stephen R. Webb, G3TPW and his wife Susan R.
Webb, G7CGS. The company was set up to design and manufacture amateur
radio equipment that
could be sold directly to the end user. The basic idea was for Steve to
his hobby and anything that he found that he needed to design and build
might be considered as a suitable company product. It was a very good
to play radio all day and every day! The Limited company was closed
Steve became a permanent employee of British Aerospace, but CobWebb
are still available from Susan, trading under her own name, S.R.Webb!
Who is Steve Webb?
Steve was born in Oldham, Lancashire on mid summers day, 21st June 1947, the peak of the peak of the sunspot cycle! His parents both came up from London in 1940, to work on the original Cossor IFF (Identification Friend or Foe) system. His father (Frank, G3ZKS) worked at RAE (Royal Aircraft Establishment) Farnborough and brought the IFF designs up to the North to be manufactured in an old cotton mill, away from all the bombs! His mother (Flo) used to teach the girls how to solder and how to wind coils and build IF amplifiers. She also taught Steve how to solder!
Steve spent a very happy childhood living in Chadderton, which is adjacent to Oldham. He always had many friends with similar interests to himself and really enjoyed his school days!
At junior school he spent the last 2 years in the final year and used to create and perform in the weekly plays, in front of the whole school, with no script and no inhibitions!! His teacher said that his diary was always full of information about model railways and rocket design! Many a young frog was launched in a cardboard nose cone atop a 2s/6d rocket, to be retrieved as it descended by polythene parachute! He wrote a marathon book on "Iron and Steel" as well as smaller efforts on "Transport through the Ages", "Marino Wool" and "Trees".
At secondary school Steve met other lads who were interested in rocket science. The field opposite the school soon had a large patch of burnt earth in it's centre, the launch pad! The school library was full of books about science, electricity and radio, so by the second year rockets had been left far behind and Steve met another group of lads, the radio enthusiasts! In the third year he started a regular weekly feature about science and radio in the class newspaper. He also wrote a book called "The History of Radio". This was actually quite good as it explained all about radio theory as the early experimenters had learnt it, and as Steve was learning it himself of course.
All this interesting work had to stop in the fifth year, as the serious business of "O" levels loomed. The school became a mixed sex school during Steve's fifth year, and his school report said,"Work has stopped this term."!!
Steve left school just before he was 16 and started work at the Post Office as a trainee telephone engineer. He had applied to the BBC to become a transmitter engineer and they had advised him to go to the Post Office for 3 years and then re-apply to the BBC!
The Post Office ran a superb no expenses spared training scheme, and Steve really enjoyed his time there. He was quite amazed when, as soon as the training department found out that he was interested in radio, he was instantly transferred to the "Transmission" group. He was sent on many training courses and studied "Telegraphy and Telephony", "Radio Communications" and "Microwave Communications" as his specialist subjects at the Tech. along with all the "Maths" and "Electronic Principles".
After just 3 years he was made an acting "Technical Officer" (on full Technical Officer pay!) in a repeater station that was located under the centre of Manchester, for use in case of Nuclear War. (The good old 1960s!!) He stayed at the Post Office for a total of 6 years and never did apply again to the BBC. The idea of sitting there in control of all that power must of lost it's appeal! He had become very interested in VHF and UHF equipment design so he joined "Pye Telecoms" as a design engineer instead.
Sue and Steve, when they first met!
Steve married Susan (now G7CGS) in 1970, her first introduction to amateur radio was when Steve's father Frank came blasting through on her radio! Steve and Sue now have three grown up children, Alex, Melanie and Jennifer. Alex, G7CGR, does most of the antenna production these days and is gradually taking over the amateur radio business side, hopefully to leave his father with more time to develop new products!
How and when did Steve become a Professional Radio Design Engineer?
Steve has been involved with communications systems design professionally since 1969, when he joined Pye Telecommunications. He designed the VHF wide band high power amplifier of the Pye “Whitehall” for the Home Office police requirement. This amplifier produced 100 watts peak (25 watts of AM) from a 10.7 volt regulated rail. He then designed all the transmit side of the AM Olympic (except PA) making sure that it tuned right down to 144 MHz!
It is interesting to note that Steve obtained his job as a design engineer at Pye Telecoms mainly because of the knowledge gained from his amateur radio activities. The training that had been provided by the Post Office obviously provided a good engineering background, but even this was helped to a large extent by his amateur radio interest. Many times when things were being explained at the Tech or on the many training courses, he would suddenly be enlightened and understand why something had happened the way it had during his G3TPW activities. The point was it all meant something to him, whilst for most of the other members of the class it was just another academic exercise.
One of Steve’s old school pals Terry Bennett, now a VE station, worked for Pye Telecoms on the sales and demonstration side. Terry drove a large bright red Long wheelbase Land Rover that was the “Pye demo wagon”, and on one of his regular trips to Cambridge he asked if Steve and Sue would like a day trip out. Whilst they were down in Cambridge Terry asked Steve if he would like to see the design labs. Steve met the Chief Engineer, the two of them talked radio for a couple of hours and a few months later Steve and Sue moved to Cambridge!
What other professional design work has Steve done?
In 1973 he joined Ferranti Semiconductors, back in Chadderton, as an RF power transistor Applications Engineer. He had been talking to the "Head of Applications" one day on the phone about the use of the Ferranti ZTX327 transistor in the "Pye Olympic" and mentioned that he was coming to see his mother, who lived just up the road from the Ferranti factory. He was invited to call in and see the lab and the factory, and was then offered a job! This job entailed designing radio telephone transmitters and power amplifiers using Ferranti devices and writing / publishing applications notes with full design information for other RF design engineers. Steve also modified customers existing equipment designs to use Ferranti components and developed transmitter and receiver circuits for specific customers, acting as a consultant. He provided technical advice to many customers, including Ferranti Microwave.
In 1975 Steve joined the Ferranti Microwave Group in Poynton, Cheshire as a Design Engineer. He re-designed the high power amplifiers of Ferranti varactor multiplier microwave sources and developed various varactor multipliers up to 14 GHz. He designed low noise and high power microwave amplifiers, phase locked microwave sources, complete microwave transmitters and UHF wide band high power amplifiers, all mainly for military purposes. He developed phase locked local oscillators and a low noise amplifier for 1.6 GHz weather picture receiver (1977). He also developed the phase locked oscillators for the worlds first reception of OTS 11 GHz TV (1978).
He was then promoted to become the Technical Manager of the Ferranti Microwave sources with design, production, test, marketing and customer liaison responsibility.
In 1979 Steve was invited to join Marconi Space and Defence Systems Ltd. in Kidsgrove, Staffordshire, as a Senior Design Engineer. He turned the offer down a couple of times because he was very happy at Ferranti, but in the end they asked him how much money it would take to get him there, so he had to go! His first task was to design the RF section of the IF simulator for the DN181 Blindfire Rapier missile system. Steve then worked on electronic warfare systems using state of the art receiver and transmitter designs. (Trying to get solid state devices to work as well as valves did 30 years ago!!
He conducted feasibility studies into the use of new techniques, produced proposals, estimates of design times and costs, technical reports, PERT diagrams etc., for an MOD research contract and then designed the receiver and transmitter modulator side of the project when the production contract was awarded. He devised an antenna test site to develop a wide band antenna and was then involved with field trials of the whole system, including the final production designs. He also acted as a consultant/advisor to other Marconi engineers on all aspects of RF and Electromagnetics design.
1984 saw a move to the wilds of North Yorkshire, when Steve joined MM Microwave of Kirkbymoorside, as Technical Director of a new Satellite Group. MM Microwave provided the finance for the development of the ASTRID (Automatic Satellite Telemetry Receiver and Information Decoder). Steve designed this system for computer enthusiasts and educationalists. It allowed any computer with a suitable serial interface to decode and display news and data from the UoSAT scientific satellites. ASTRID was Steve’s idea from original concept to final production.
After the design phase, MM Microwave provided business back up, production facilities, staff and finance, whilst Steve provided technical help, plus production and marketing organization, whilst self employed, as a Radio Communications Design Consultant/Engineer. He then designed and built prototype receivers for UoSAT and weather satellites for other companies that supplied education equipment for schools and colleges and took over all aspects of ASTRID from MM Microwave.
In 1987 SRW Communications Ltd., of Swinton, North Yorkshire was formed, with Steve as Company Chairman and Managing Director. He designed the “Loudenboomer” 400 watt output linear amplifier for the 1.8 to 30 MHz amateur radio bands, the “CobWebb” antenna for the 14 to 28 MHz bands and the “Spider” and “FlyTrap” antennas for the 1.8 to 10 MHz bands. These antennas were designed to provide maximum performance with minimal EMC problems, so that high power could be used, without the usual problems. The “CobWebb” antenna represents a major step forward in amateur radio antenna design, allowing world wide communications to take place from typical urban domestic locations, without the normal planning permission and EMC problems.
In June 1996 Steve secured a 6 month contract with British Aerospace at Brough in East Yorkshire to oversee the technical aspects of the design of an HF antenna system to be fitted to the “Hawk” military training aircraft. When this project was completed he was persuaded to join the permanent staff of British Aerospace to take over the EMC and Lightning design aspects of “Hawk”. He became the “on site” Electromagnetics specialist at Brough, whilst continuing as a freelance Design Consultant and the Technical Advisor to SRW.
First Flight of the F18 cockpit Hawk, in it's undercoat!
The work at British
Aerospace has had the unfortunate effect of vastly reducing the amount
of time available for development of the “G3TPW Ultimate HF beam”, and
meant that the existing products have not been marketed in any way.
is about to change as the G3TPW CobWebb Web Site becomes operational!
How did you become interested in Amateur Radio, Steve?
As a child, I was
in things electrical. When the war was over my father had
a company “Aerotron Radio Ltd.”, to design and manufacture radios
and amplifiers. I was sent to nursery school when I was 3, so that my
could take up a job with the Civil Service. In those days even civil
had to work on Saturday mornings, so my father used to “look after”
me at the “works”. I had lots of toys to play with, potentiometers,
resistors, coils, capacitors, bulbs, batteries and bulbs. I well
remember being frightened by the sparks produced as I connected
my little circuits
(bulbs and buzzers) to my 6 volt accumulator, my little 2 volt cell was
tamer. I was 4 years old at the time!
Steve Aged 3 and the Aerotron Van
So I guess you could say that I was indoctrinated from an early age. I went through the usual childhood interests, meccano set, steam engine and then an electric train set. I remember re-discovering “circuits” when I was about nine, in fact I remember feeling very frustrated at one stage when I could not get a circuit to work. I knew that I used to know all about those things when I played round at the “works” in my pre-school years!
My parents separated when I was six, I often wonder how much more I would have learnt if my father had been around all the time, instead of just for visits. He continued to influence me though, it was he who bought me my meccano set, steam engine and train set!
I became very
model railways, I used to build up the Air fix kits and then moved on
balsa wood buildings and papier mache hills etc. I devised a signalling
using very thin wire, 38 swg I think, supported by the scale telegraph
The system used morse keys made from meccano and those same old
buzzers from my pre-school days! I still remember some of the codes,
dots meant an express train was coming on the fast track!!
As I developed the model railway I learnt about transformers, rectifiers, potentiometers and control circuits. I had to clean out the slots on the commutators so I learnt about electro-magnets and permanent magnets, i.e. how DC electric motors worked.
By this time I had started at the secondary school and boy, did they have some good books in their library! I discovered a fascinating book called, ”The Boy Electrician”. One of the construction projects in it was “A Crystal Set Radio” !
A large mast was fabricated from some old wood and my first aerial wire (made from plastic covered steel garden wire) connected. A visit to “Gilberts” radio shop in Oldham allowed me to procure a germanium diode, a mica spaced tuning condenser and some “double cotton covered enamelled copper wire” for a coil. One of the lads at school had an uncle who worked at the BBC, a pair of high impedance headphones were thus obtained! All the connections were made by just twisting the wires together and the results were fantastic. The BBC Light Programme and the BBC Home Service!!
I remember asking my father where the electricity came from to power the crystal set. He just said that it came from the aether. If he had explained it better perhaps I would not have remained as fascinated by radio for all these years! It seemed to be total magic to me!
I was looking through some of my fathers old war time radio magazines one day (Wireless World in newspaper format!), when I came across an article about a certain Mr. W.E.F.Corsham, G2UV, who had invented something called a QSL card. Note. I did not have to look this up, his name and call sign are indelibly etched into my memory! I asked my father what this was all about and he simply said, “Amateurs” and showed me two positions on the “Short Waveband” of the family domestic radio, an old Aerotron prototype!
So I tuned round 40 metres and heard such characters as “Gee Three Motor Torpedo Boat” and “Gee Three Item Oboe Love”. I tuned round 20 metres and heard VQ4 Radio Frequency describing his transmitter output coil, which was made from half inch gas pipe wound round a beer bottle! I WAS HOOKED!!
What is it about amateur radio that interests you so much?
Must think more about this one. Originally it was the honour of being able to listen in to the conversations of these higher life forms!! Pure technical. Magic. Ego, my sigs better than your sig!! Sense of achievement when works. Opportunity to speak to people all over world. Was this before internet. Way of meeting people with same interests, again before internet.
What interested me in the past. Satellites, moonbounce, aurora, new modes, weak signal DX on 160 metres, microwaves. Practical propagation experience from 1.8 MHz to 24 GHz, using aurora, tropospheric scatter and refraction, ionospheric scatter and refraction, moon reflection, meteor scatter, sporadic E and satellite modes. All equipment home designed and built, using AM, FM, phase modulation, double sideband reduced carrier, single sideband, infinitely clipped ssb, fsk, and cw emissions.
Lecturing at radio
clubs, not only on SRW products!!!
Part Time Lecturer for 6 years (1978-1984) at Macclesfield Technical College. City and Guilds Radio Amateurs course.
Part Time Lecturer at York College of Further and Higher Education (1987-1995). Radio Amateurs, Electronic Principles, Electronics, Telephone Switching, Instrumentation and Control up to “HNC” level. Also had to set and mark course work, projects and examinations.
Feeling of getting
somewhere when get people interested. Not just in passing the exam, but
really interested. Gives one a sense of immortality, knowledge being
passed on to future generations etc.
What type of work do you like doing?
Writing technical articles. System design. New concepts. Original
circuit design. Building prototypes. Product line/marketing advisor.
Demonstrating and explaining
products. Designing and developing antennas. Inventing technical
to problems. Evolving production systems for my designs.
Electromagnetics design. EMC problem solving. Fundamental research.
These days, Electromagnetics Theories, Electro-dynamic radiation theory, antenna design proof of pudding etc.
Amateur Radio wise, I still like to work ZL and VK and the tropical islands etc. Not interested and never have been interested in contests. Used to use contests to get a few reports, but can't even do that these days cos they give you 59 all time. Sometimes go on with 10 milliwatts, I still get 59 but its a struggle so you know the signal is pretty weak really!!
Please excuse existing note format. To be expanded when I have more time!!
How did you learn the radio theory to get your Transmitting licence?
My model railway had given me a background knowledge of electrical circuits etc., but I guess I learnt the basics of electronics from the radio books in the school library. In all the construction projects the function of every component was explained, so that you understood exactly how the circuit worked. It was a lot easier to explain circuits when they were all using valves! Later on I found a war time copy of the ARRL Handbook in my fathers bookcase, so I used to read and re-read all the theory chapters for hours and hours, to cover the more advanced stuff.
I wanted to learn all about the theory of radio because I was curious about the magic of it all, and I wanted to improve my reception. My first crystal set radio would not pick up the BBC Third Programme, without having the Home Service in the background so I added another tuned circuit to improve the tuning, and thus learnt about top capacity coupled parallel tuned circuit filters and adjacent channel selectivity!
I could not get Radio Luxembourg so I erected a 250 end fed wire. I also made a new coil using thick copper wire. This was wound on a square wooden former and the enamel insulation was rubbed off one corner. I then used a cotton reel as a pivot for a piece of meccano strip, which was twisted through 90 degrees such that the edge could be arranged to make a sliding contact on the coil. The end of the strip then protruded through the wooden front panel and formed a Sliding Tuning Control! This meant that the tuning was being accomplished by a using a variable coil, so I could then use a fixed value silver mica condenser. This seemed to me to be a much more sensible way to effect a variable tuned circuit, it was much easier to make a variable coil than a variable condenser.
I discovered that this coil worked much better than anything I had tried before. I did not know anything about “Q”, but I had discovered its effects! Radio Luxembourg came in great with the tap on 26 turns and I then found that by using a matching transformer (an audio output transformer from an old jumble sale valve radio) I could listen to the Home Service on a 3 ohm loudspeaker !
It is interesting to note that I had no real need to make a radio, we had a perfectly good family domestic radio sat there on the sideboard, but I just wanted to make my own! I used to collect old non working radios from neighbours and friends, and try to get them working. Most of them used to hum, the old wet electrolytic smoothing capacitors used to dry out! If I could not fix them I used to pull them to pieces and add all the components to my ever growing junk box.
The Winter Hill TV transmitter site had had an open day and one of the older lads at school, a 3rd former, had met G8OJ and G3MYR up there. They had told him about the “Manchester and District Amateur Radio Society” and had even worked out how we could get to the meetings by bus!
The club really encouraged the youngsters and I learnt much from Barry, G3IOA who gave an hours RAE talk every other week when the club had a “Natternite”. Cliff, G8OJ also provided morse tuition and every other week there was a full blown Lecture. I remember it seemed very funny to be told to call “grown ups” by their Christian names! I found the full lectures really interesting, although at first I only understood a very small part of what was being said!
The club had a station (G3HOX) set up on 160 metres, and quite a lot of the members were on 160 metre mobile. All of the equipment was home brewed, real home brewed, not just home built using other peoples designs like they do these days. I had to get on 160 metres! I met lots of other “Short Wave Listeners” of similar age to myself, so the old push bike got quite a bit of use on visits to other peoples shacks. We all got our licences eventually, so it is obvious that we were a really enthusiastic group. We started to meet at the many radio shops in Manchester, every Saturday morning. NW Electrics, RST Components, New Cross Radio, Globe Radio, Mazels? and others that I can't remember the names of.
One very important lesson that I learnt at this stage was that it is best not to copy other peoples circuits, if you do not understand exactly how they work. I built a transistorized morse code oscillator and it did not work. I was really upset by this, but I could not sort it out because I did not know how it should have worked. Years later when I realized that it was a three section RC phase shift oscillator I might have stood a chance of getting it going! The books never seemed to explain how transistor circuits worked, not like in the good old valve days!
I eventually asked my father for help, he did not know much about transistor circuits but showed me how to design my own circuit using a valve. He explained about feedback on amplifiers, when the microphone was placed near the loudspeaker and then drew a triode valve with part of its output coupled back to its input via an interstage coupling transformer. He showed me how to put bias on the valve and suggested some component values.
I built that valve oscillator and it worked! The frequency was a bit high so I put a capacitor across the transformer to reduce it. It used a 1T4 battery valve, with expensive HT and LT batteries. I never did get that battery eliminator made, but it certainly taught me about the battery economy advantages of transistors!
I discovered that if I connected a wire from the gramophone pick-up socket of the old Aerotron radio, to one of its extension loudspeaker sockets, via a small capacitor, I could make it howl. I made a morse key from meccano and hey presto, I had a morse code practice oscillator. The meccano key was not too good for sending proper morse so I paid 1s/6d for a proper one from New Cross Radio, I was 12 years old when I screwed this morse key to a block of wood with 2 odd screws that I had to hand. It was only a few years ago that I added the other 2 screws, I have used this key all my life and have never had any desire to change it!
My father bought me a Canadian Marconi 52 set receiver for my 13th birthday, so at last I could listen on 160 metres to all the locals. I found that with my 250 foot wire and an ATU (made from a 500 pF variable tuning capacitor and a big coil with a 4 turn link coil to feed to the 52 set) I could hear lots of stations that the locals could not, 160 metre DX!!
I spent many many hours listening round the amateur bands, when I should have been doing my homework. I was mainly interested in all the technical chat by the people who were building and improving their rigs, the more I learnt the more I realized how little I knew.
I discovered that I could hear the local oscillator of the broadcast radio on 160 metres if I tuned the broadcast radio to a frequency 465 kHz lower than the 160 metre frequency. The radio used the standard valve line up of the time, 6K8 mixer and local oscillator, 6K7 IF amplifier at 465 kHz, 6Q7 detector, AGC and audio, and a 6V6 audio output with a 6X5 rectifier.
I then found that if I wound a link coupling round the local oscillator coil and switched this into the ATU in place of the 52 set, other people could hear the local oscillator as well! I put a carbon microphone in series with the link coupling and found that other people could now hear what I was saying! The modulation level was very low so I decided to invent a new form of modulation.
I called this new form of amplitude modulation “absorption modulation” because the idea behind it was that a carbon microphone absorbed varying amounts of power in sympathy with the speech waveform, to produce a standard amplitude modulated signal! The carbon microphone was connected to a second link coil on the ATU. I thought that amplitude modulation was simply variation of the carrier frequency level at the audio frequency rate, that was what it said in all the books that I had read!
I found out that it worked better if I introduced a diode into the circuit. My idea was that this would produce a DC bias for the microphone. I then found that if I fed audio from the loudspeaker socket of the radio into the ATU link coil via a diode and used a pair of headphones connected into the gramophone pick up socket of the radio to act as a microphone, the modulation was even better. I called this “Diode Modulation” but I had no idea that the diode was acting as a mixer and producing the AM sidebands! The books with their simple explanation of AM were all wrong!
I then read an article about choke modulation and realized that if I connected the HT feed to the local oscillator to the anode pin of the audio output valve, the output stage would act as a choke modulator. The output transformer would act as a choke and the system would be able to produce 100% modulation with ease. I also removed the series resister that was reducing the voltage to the local oscillator, this now made the oscillator run at an input power of over 300 milliwatts! With this little transmitter I found that I could talk to other stations all over the country, of course the 250 foot antenna helped a lot. My mother was not too pleased about the radio though!
The next project was a higher power transmitter. In those days everybody was paranoid about the Post Office Interference Service and their ability to catch pirates. My little modified broadcast radio was ideal, every time G3IOA paid one of his surprise visits there was no sign of a transmitter. My new transmitter was built into an old gramophone player carefully placed next to the broadcast radio, which was used as the power supply and modulator.
It was a real covert operation, almost like the wartime spy operations. The transmitter was a 6J5 triode valve wired as a Hartley oscillator that was again choke modulated by the 6V6 in the radio. It ran about 5 watts and I was now a big signal on Top Band. It worked quite well at the top end of the Medium Wave as well, but that's another story!!
The problem was that this transmitter was too good, people could recognize my voice. Some of the other SWLs at the club had got 19 Sets working, and we used to have nets on 160 metres after 4 o’clock, before the grown ups got out of work!
I then designed and built my first complete transmitter. It was a single valve unit using a 12AT7 double triode valve. One half was my good old Hartley oscillator design and it was choke modulated by the other half, which was driven by a carbon microphone. I lent this out to a near neighbour and we used to have many many QSOs that went on for hours on end. We used to work duplex, none of this amateurish over to you malarkey!
Then one evening at the club G3IOA announced that pirates would not be tolerated and we would all be thrown out of the radio society unless we stopped! We were all persuaded to fill in the forms to take the RAE.
We did not need to enrol at the local technical college to do an RAE course, we had already learned enough about amateur radio to pass the exam by actually doing the amateur radio. One point that I try to get across to people who have just become interested in the hobby is that you do not need to have a transmitting licence to enjoy amateur radio.
You can learn so much about amateur radio and really enjoy it at the same time, just by getting a receiver and listening on the bands. You can learn even more by building a receiver and then perhaps designing your own. You do not need to be transmitting to learn about radio, but I must admit actually designing and building the little transmitters taught me a lot!. Whilst you are talking you are only repeating what you already know, if you listen you might learn something!!
I always say that I did it the easy way, I learnt about radio whilst enjoying the hobby as a "Short Wave Listener". I spent my 5 year apprenticeship enjoying the hobby, and learning at the same time, before I got my licence. I have often found that people on my RAE courses that I have run at local colleges over the years, start off regarding the RAE as a necessary evil to be got over before they can enjoy the hobby. To my mind this is totally wrong.
I could never understand why my RAE students would not join the local radio club, a frequent answer given was that they would join the club when they had got their licence. Were they scared of being looked down upon? I did think that this could have been due to the fact that most of them had come into amateur radio via CB, but I now suspect that it was often more to do with only being allowed out one night a week!
These days CB provides a great opportunity to play with transmitters and antennas without having to worry about getting caught! When I lived in Macclesfield we used to have the radio club net on Channel 38, so that all the Short Wave Listeners could join in. I was known as "The Teacher" and I recruited many people onto my RAE classes this way!
How did your Amateur
Radio career progress?
When I got my licence I started up using G3IOA’s old 160 metre transmitter (bought for 10 shillings at the club junk sale!) and the 52 Set receiver.
By this time I had left school, and was working for the Post Office Engineering Group, so I had some money to spend! I bought three No 19 Sets from New Cross Radio. They cost 27/6d each, the real smart looking ones were 55 shillings! I modified one of them into a receiver only, with its own in built mains power supply. I played about with the other two and managed to put out a few odd transmissions here and there.
I bought some old RADAR equipment, RF24, and RF25 units, which I used to extend the frequency coverage of the 52 Set. I already had an RF27 unit from my SWL days. The RF27, was bought at a club junk sale and was a cast off from G3PJK. Vic had modified it to be band spread so that it just covered the 4 metre band, plus a little extra for Jodrell!. I used to listen to Jodrell Bank conducting their RADAR moon mapping experiments. The 250 foot dish put out a good signal on back scatter!
I soon got cracking building my own rig, so I could get on the higher frequency bands. I decided that I would use the modular approach for all my amateur radio equipment, I still use this philosophy to this day. I had already built a large mains Power Supply Unit, that I thought would serve for all my future needs. This used all ex-military components obtained from New Cross Radio, oil filled transformers, chokes and capacitors (the oil filled paper capacitors were dated 1935!!). I spent hours drilling a series of holes for all the cut outs in the eighth inch thick black iron chassis. I then had to file them all smooth. This really was a mammoth task, it taught me to always use aluminium in future! The PSU had multiple output connectors and gave out 600 volts at 250 mA, 300 volts at 250 mA and 6.3 volts AC at many Amps for valve heaters. Up to a year ago this power supply was still in use! 35 years service and most of the components were at least 20 years old when it was built!
I decided to build a transmitter to cover all the HF and LF amateur bands. I went down to NW Electrics (G3MAX) in Manchester. Fred recommended that I use a commercial VFO (Variable Frequency Oscillator) and I think I paid about £10 for a “Geloso” unit. This Italian company used to supply the British company “KW Electronics” with the VFO for their transmitter, the “KW Vanguard”, so I thought that it must be OK. I also bought a band switched PA tuning coil and a 6146 transmitter PA valve from Fred and he gave me a sketch of the “Vanguard” power amplifier circuit.
I built this up on one of Fred’s standard size aluminium chassis that he used to manufacture and fitted it into one of the old No 19 Set cases. It had two valve sockets on the front panel, one for the PSU and one for the future modulator. This transmitter worked really well and I learnt a lot from it. At first I had problems with arcing of the relay contacts that were switching the 600 volts. By talking to people on the air I soon discovered all about spark quenching resisters and capacitors, much better than learning about these things at tech or on some training course! The “Geloso” VFO did not cover the 160 metre band so I had to modify it to do this. I think I got the information on how to do this from an old Short Wave Magazine.
I put up a G5RV antenna and found out that it tuned up on all bands, 160, 80, 40, 20, 15 and 10 metres, with the Pi network tuning in the transmitter. I soon discovered that if I put up a dipole antenna for the band that I was mainly interested in at the time, results were far better on that band than with the G5RV. So I used the G5RV for general purpose use on all the bands and for comparison with other special antennas.
I was not too keen on CW so I hooked in the modulator from the old G3IOA 160 m transmitter, I could now run 10 watts of AM on all the HF bands. To run the transmitter at it's full power (60 watts DC input), with 100 % modulation, I needed much more audio power.
I bought an old American surplus modulator from Fred's. It had a pair of 807s driven by a 6V6. I couldn't understand the circuit so I stripped it down and used a circuit out of the RSGB handbook for the output (pair of 807s in AB1) and designed my own speech amp using a 6N7 into a triode connected 6V6. This used 300 pF and 500 pF coupling capacitors, which gave a good treble boost to cut through interference, with the Acos 43-5 crystal mike insert built into an old 19 Set microphone case.
I bought and built a
Heathkit RA1 receiver. This was a good valve receiver for amateur bands
only 160 m
to 10 metres. I ran this set up on the HF bands (60 watts AM, 75
CW) until 1968, in parallel with the other higher frequency activities.
was a good rig and I worked stations all over the world, mainly using
The HF bands set up circa 1965
In 1966 I designed and built a solid state transmitter for a 160 metres GM land expedition on CW only. I started with an OC169 VFO, OC169 EF, OC169 buffer, AUY10 driver into a 2G240 PA. I later added an amplifier with a pair of AUY10s in it, this gave about 20 watts RF output, real QRO for transistors! It was all built into a small aluminium box and included a parallel tuned circuit ATU for direct feeding of a half wave end fed wire. A child's box kite from Lewis's in Manchester provided the support, using the on shore/off shore breezes of the Scottish coastline. I had many QRP QSOs as the transmitter was being developed, starting when I had the first 3 stages going.
My friend Steve, G8AJB designed and built the receiver, which was a single superhet with a very narrow crystal filter at 455 kHz. The system worked extremely well and during the July of 1966 we travelled anti-clockwise all round the coast of Scotland, staying at different bed and breakfast establishments every night! We gave many stations their first contact on 160 metres with many rare counties, in those days people were mad keen on collecting all the British counties. If you had 98 worked and 98 confirmed you were really somebody! The most memorable QSO was with Portpatrick Radio! He invited us round for a cup of tea and a chin wag, and of course showed us his rig!
Back at the home QTH I continued to improve the HF bands signal. I found that I could get to the States on 160 metres when I used a half wave end fed wire and a roller coaster pi network ATU. I also tried a 66 foot vertical 66 foot horizontal inverted L system fed with 35 ohm co-ax against a massive number of ground rods and buried radials. It seemed to work well on transmit but was very noisy on receive. I tried a 500 foot triangular horizontal loop. It was OK on 160 metres but very poor on all the other bands. I had hoped that it would work on all the HF bands, as somebody had told me it would. It tuned up a treat on all bands up to 10 metres, but a dipole worked much better!
I tried ground planes on 40 metres and 20 metres but dipoles were always better. Looking back now I think my problem was that my ground planes were always fairly low so the radials were near other conductors or the ground. It was quite easy to get my dipoles up in the clear so really it was an unfair test of the ground planes. I tended to shy away from verticals because of TVI, I also avoided 14 MHz and 21 MHz, because whenever I went on these bands I always seemed to get a new complaint!
I spent a lot of time on 10 metres with a dipole antenna made out of two 8 foot tank whips. There was no TVI with this antenna. I made an indoor cubical quad for this band but it was never as good as a dipole out in the clear. It was on the landing over the stairs and used to be de-tuned as people walked through it!
My favourite band was always 160 metres. I did not have too much TVI using the half wave end fed wire on this band, once the Post Office Radio Services sorted out the 27 local Pye television sets that received on 1.9 MHz!
By this time I was a Post Office Technical Officer, working in a repeater station and I got to know the members of the PO Interference group very well. In those days people paid their TV licence fee to guarantee them interference free reception. The Post Office would come round and supply any filters needed all for free. The amateur had no need to get involved, if they got interference you just gave them a form to fill in. Even so, TVI was still a hassle and not a nice experience.
One evening the Executive Engineer in charge of the Post Office Radio Services Division called at our house, with the offer of job working for them. He said that he thought it might be better if I was on their side!! I decided against it because of having to work in the evenings.
I built the 4 metre RSGB 6146 PA design which produced about 35 watts output on this band. It was modulated by the common modulator and fed from the same PSU as the HF band rig.
I then built my 70 cms station, with 2 metres as an aside. I never operated much on 2 metres, although I made a cubical quad antenna out of co-ax and it worked quite well. 2 metres seemed to be full of posh people with bought rigs. The Cheshire set, we all dress for dinner etc.
I designed the 2 m Tx using valves and a tinplate chassis. Solder seams etc. cut out with tin snips. Use feedthrough capacitors so all non RF components on top of chassis and all hot bits underneath EF91, EF91, 5763, QQVO 3-10 about 6 watts RF O/P
This is the 2 m tinplate transmitter
70 cms tripler QQVO 3-20 6 watts RF O/P. Note use of two old halfpennies as tuning capacitor! Very nice 1 inch diameter discs!
I later built a
and modified the valve tripler into a straight amplifier which gave
12 watts RF output.
G2DD 70 cms converter (RSGB handbook design)
and transistor pre-amp.
14 ele Labgear antenna £2 from one of the University summer students at work, G3RVR.
23 cms. 2C39A tripler, 6 watts RF output at first then reduced to about 3 watts after running the valve with no heater supply for long periods. (Using RF back heating of the cathode) K6AXN converter and an 8 over 8 antenna made from brazing rod.
1969 decided to make all new solid state equipment Sold or gave away all existing gear. Years later saw my old HF bands transmitter on display at the home built equipment competition of the Belle Vue radio convention!!
1970 new house in Cambridge build shack in loft, complete new tx, rx and converter system. Never get rid of your old equipment before you have built the new stuff, it takes a lot longer to re-build than you think!!
10.7 MHz fix tuned receiver 50 ohm i/p modified Pye Westminster boards. home brew 10.245 VFO to convert 10.7 MHz down to 455 kHz with variable bandwidth. (Overlapping crystal filters on 10.7 MHz and 455 kHz) 100 Hz to 15 kHz bandwidth. 455 kHz splitter feeding FM IF board with noise operated squelch and AM IF board with home brew "S" meter and BFO for CW and ssb reception. All built in pcb box.
My new construction technique, pcb. can solder screens etc. easy to cut with hacksaw and can be drilled and filed. build circuits on 40 mm wide strips of single sided pcb using 3 mm wide strips of double sided pcb cut up as required (using standard wire cutters) to form stand off insulator sections or pads. These pads reflow soldered into position. better than gluing because can move them if you want to make changes. The prototype becomes the end product. When finished building developing and testing a new circuit on long length of 40 mm wide pcb, cut it off and solder directly into pcb box. build in modules so can be re-used in future projects. etched pcbs waste of time, only useful for mass production not for one offs.
4 m and 2 m converters using VCOs with direct conversion to 10.7 MHz. was going to use a phase locked system, but found the VCOs to be so stable that I carried on using a manual tuning system using 2 pots for fine and coarse tuning, with a large meter to indicate the frequency!
Regulated 14 volt PSU with 3 stage feedback system very similar to that used on the "Pye Whitehall" equipment.
4m Tx dipole fm for no TVI. PA of 4 metre Tx very similar to that used on the "Pye Whitehall" equipment.
2m 150 watt solid state tx. Maximum legal DC i/p power but 80 % efficient so gave 120 watts of RF output. Worlds first solid state moonbounce but only got a few weak echoes etc. We borrowed the Cambridge Universities radio telescope antenna for the receive system, but it was resonant on 153 MHz or somewhere and did not work very well on 144 MHz.
70 cms transistor tripler amp and a 30 watt PA.
23 cms Tx Transistor parametric tripler.
28 to 30 MHz tuneable IF converter to 10.7 MHz using dual gate mosfet rf and dual gate mosfet mixer. 2 dB noise figure, 30 dB maximum gain with 40 dB gain control.
Receive converters for 2m and 70 cms using crystal osc chains to convert down to 28 to 30 MHz.
1296 MHz down to 144
for 23 cms receive.
1973 moved back up north to Royton, between Oldham and Rochdale. Mainly active on 4m and 2m with 10 m down link for satellites.
The Royton antennas for
4 m and 2 m
OSCAR 6 etc Beams and
tilt over system etc 17.3 to 19.3 MHz VFO for a more stable 28 to 30
MHz receiver system. In own box with 50 ohm co-ax socket output.
High frequency so
no harmonics in amateur bands.
70 cms QRO etc
OSCAR 10 etc beams and how to tilt over and calibrate direction etc
Computers UoSAT etc Radio club and tech RAE etc
The 2 m and 70 cms antennas at Macclesfield
2m ssb rig computer club TVI with clubs rig on 15 metres etc TVI filter design
Microwaves 10 GHz and 24 GHz Phase locked 10,368 MHz onto 144 MHz exciter
1979 North Yorkshire. UoSAT 2m ssb pa etc Inf clipped ssb 10XY Phasing
1989 Return to HF, Bought HF rig!!! Was going to design down converter for 2m ssb rig but thought of Loudenboomer as a company product so the company bought a signal generator called a Yaesu FT 747! Needed quick don’t need to re-invent wheel HF Antennas CobWebb Spider FlyTrap Loudenboomer beam antennas
1999 Computers PC and Internet. Buy equipment for 2m and 70 cms!!! Antenna for car
Web site to market
Please excuse existing
note format. To be expanded when I get some time!!
What books or web sites can you recommend to learn all about antennas?
All the books and the sensible web sites that I have seen stick to the standard agreed ideas. All confirming one another’s views and back patting. No original thoughts or even direct measurements of actual reality. Computers Rule OK? There is a certain perceived wisdom about antennas, and nobody seems to want to be different. Mathematical evaluations of antennas can be full of assumptions, statistics are math! The math may be correct, but it might not represent reality!
How exactly is the energy stored in a magnetic field? What is a magnetic field? Can a magnetic field exist without movement of electric charge? And then the real cruncher, is a magnetic field just the effect caused by the movement of electric charge? I never was too happy about magnetic fields being separate entities in their own right, but I still use them when I am doing analysis work. It is often much easier to visualize and understand what is going on in terms of magnetic fields rather than electro-dynamics!
Computer simulation merely puts pre-conceived ideas forward as fact. So called computer design is often merely analysis of an existing design. Computers are not very good at invention but they can try a million different combinations very quickly! They are also very good at looking through and re-arranging long lists. Any knowledge that a computer has, has been programmed in. At the end of a computer design process you still have to apply the PCO, (Post Computer Optimization) to make sure that it is right. When you make something new you have to test it.
In reality it does not matter how things work exactly. What does matter is that designs are based on reality (which must be correct) rather than theory (which at best will be incomplete and at worse incorrect). My philosophy has always been to start with something that works and the try to improve it, using very carefully made direct measurements. Do not have pre-conceived ideas about what should and should not work. One day I will write my book on antennas, when I retire!
My ideas about how antennas work have evolved from all my experimental work on antennas over the years. From experience I know what works and what does not work. It does not really matter exactly why things work the way they do, but we all like to have an explanation. I started from the fundamentals and slowly determined my own theories that seem, to explain all my actual measurements. These theories explain many things that conventional theories do not cover, it was really interesting when lots of effects that I knew about were suddenly easily explained. All I have done is put my understanding of antenna operation into words.
My theories do not really matter. They were just devised to explain the known facts for my own use. My theories do explain why some small antennas produce very high local field strengths, even though they do not put out good signals. The point is I already knew that this happened, so I did not learn anything from the theories! What are important are the known effects, verified by careful measurements. The only thing that does matter is reality and there is only one reality! The facts came first and the theories followed on.
It is interesting to note that on the internet there are lots of people who have got this all wrong. They invent the theory first and then spend all their time on the internet telling everybody all about it. They never seem to bother about doing any accurate meaningful measurements, it's their personal theory and it's damn well right!!
There are the web sites that are designed to convince people that they have a new magic antenna for sale. It is funny that I cannot hear these 30 kilowatt broadcast stations in Egypt, that are using antennas that are supposed to be 6 dB up on a full size quarter wave vertical! Other stations from the same part of the world are very strong though. Just a little higher in frequency at 1.8 MHz, even the amateur signals are S 9 plus many dBs!
So I can not tell you what books to read or web sites to visit to find out all about antennas. Books that I have enjoyed reading are “Antennas” and “Electromagnetics” by John Kraus, "The ARRL Antenna Compendium", "The ARRL Antenna Book" and “Antennas for all locations” by Les Moxon. W4RNL and G4FGQ have good web sites that are valuable sources of standard information. The newsgroups also have a lot to offer. I only monitor sci/physics/electromag and alt/amateur radio/antennas these days, they seem to be the best ones.
How do you design antennas?
The original idea is often just inspiration or accident as you are playing with existing designs. Then I sit down with pencil and paper and sketch out various ways of implementing the idea, and perform all the calculations. All the different options have to be analysed to come up with a practical end product that can be easily manufactured at as low a price as possible without compromising performance or reliability.
How do you evaluate antennas?
The most important aspect of antenna design is the measurement of results. What we want to do is to produce the strongest transmitted signal possible and have the best signal to noise ratio on receive. We must not make any assumptions without very careful analysis involving actual measurements and must not have any pre-conceived ideas about performance. It is very easy to convince yourself that your latest creation is better than anything else that has ever been invented!
It is a very good idea to test as many standard antennas as possible. This provides you with the necessary measurement skills and gives you confidence in your results. It also teaches you a lot about antennas. I once spent over 100 hours proving that the latest magic miniture antenna was 35 dB down on a dipole. I really did work hard trying to prove that my analysis and calculations were wrong because I wanted it to be a new breakthrough, using manipulations of Maxwell's equations!
There is much folk lore in the amateur radio perceptions of how antennas work. I have enjoyed trying to find out where many of the mistaken ideas actually come from. I have found that most of them are like some old wives tales. They are based upon experiences in a certain set of circumstances, that have then been applied as a general rule. I have found that some of the tales are true but the wrong reasons are given as an explanation. I find that unravelling the mysteries of antennas is much more interesting than any other aspect of amateur radio. That’s another title for my retirement books, Amateur Radio Antennas, Facts and Fallacies.
Direct comparison tests
on air. Comparison with other stations nearby. Can be problem with
etc. even if peak power same.QSB QTH slightly different.
Some stations run a lot more power than they say they do. Ego problem. Legal levels TVI etc good leveller. Can say that need technical knowledge to operate high power with no TVI so as long as make the amateur responsible for ensuring that he does not cause TVI self regulating. If the amateur does not know how to cure his TVI problems with 100 watts then he will have to join the QRP club. If he can operate with 5 Kilowatts (and some of them do) then good luck to them. The only problem comes when they are using the excuse that their signal is so much stronger than all the others because of the special antenna system or the particular soil in their garden!
Two antennas side by side with isolation. Very important that antennas have lots of isolation, otherwise results can be totally confusing. One can act as director or reflector for other, or most of the radiation can be taking place from a different antenna to the one that you are feeding power into!
I remember when I first got my licence I was testing out a 4 foot long base loaded whip antenna for 160 m. It was sat on top of my transmitter in my bedroom shack. I found that I could work the South Coast with ease, and I really did think I had come up with a magic design for the coil or something. It was a few weeks before I noticed that if I put a neon bulb on the end of my 250 foot wire, which came in through the bedroom window and ran across the room to the ATU, it would light up very brightly every time I transmitted on the whip!!
Can instantaneously switch on Rx and do thousands of tests. Can even switch electronically and display on oscilloscope. Must make sure both antennas have 1:1 SWR and must test first with 2 identical antennas to prove the test system. Assume reciprocity theory correct but must be careful and watch for noise effects on the “S” meter. Must always be looking out for possible problems leading to incorrect measurements. Always playing devils advocate and try to disprove your own work. If “S” meter responds to noise pulses then can show a higher reading on a noisier antenna. If the noise pulses are very short then the antenna with the noise might still sound just as good as the quieter one.
I always start off by testing two antennas side by side, with at least 20 dB isolation between them. My reference mast is due south from my main mast and I always conduct my tests to the east. This maintains my isolation. I find that the path to Perth in Western Australia is very stable and it is also almost exactly due east. India is about half way, so is useful to check out the shorter range propagation.
Most of my tests so far have been conducted at the standard height of 35 feet. This is what I consider to be the optimum cost/performance height for HF antennas on a typical suburban house. A standard 20 foot aluminium pole on "T and K" wall brackets, or a small tilt over mast/tower is all you really need to be a big signal all over the world, as long as you have the correct antenna on top of it! Yagi beams and straight dipoles need to be higher to be at their best. Their electric fields are not confined so losses will be introduced by any surrounding trees, buildings, TV antennas and other amateur radio antennas.
Real enthusiasts go for 60 foot towers, not my idea of amateur radio, not best value for money. Will do tests at 45 feet and one day might even get a tower. Did consider getting one because a company expense but would need planning permission and could not be bothered. Also too slow when putting antennas up and down every few minutes for development. Think that’s one reason why people waste so much time with computers, it takes too long and is too difficult to take their antennas down to make any changes to them.
My philosophy is that I must be able to raise and lower antennas single handed in under 10 seconds and with no effort at all. Electric winches are far too slow. When the antenna can be raised and lowered this quickly it will be found that it is quicker to make a change to the antenna and measure the result, rather than input the data to a computer program and see the effect. This technique has the added advantage in that it is actually real!
Manual tests can be done on transmit with other stations but you have to conduct thousands of tests to overcome the QSB diversity problems, and people are often unreliable witnesses. The signal to local stations is being measured at zero degrees elevation, which may not be the angle that the signals on the air are being received from. The main problem is still that peoples "S" meters can not detect small changes in signal strength. When you are developing antennas you need to be able to measure to a fraction of a dB.
Another way to measure the transmitted signal is of course to measure it directly with a field strength meter. Ground reflections have to be taken into account when conducting these types of measurements as up to 6 dB of extra gain can be realized if you are not careful. This method still suffers from the same zero degrees elevation problem, as per using local station reports, so this must be taken into account. Modelling can be done on higher frequencies, but I find that the effect of the ground is very different at 144 MHz than 14 MHz.
To make accurate field strength measurements you need to have a field strength meter that is sensitive enough to provide a reading from a distance of at least 5 wavelengths. You also have to make sure that the FSM is not activated by any other local transmitters. Local TV transmitters can produce high field strengths at sometimes surprising distances, they run an awful amount of power. I had to include a filter in my design to get rid of the Bilsdale TV transmitter that is located about 15 miles from my QTH.
My system consists of a home designed and built remote FSM that drives a voltage controlled audio oscillator which modulates a telemetry transmitter. Thus by swapping the antenna and then adjusting the power output of the test transmitter until the frequency of the received tone is exactly the same, the difference between the two antennas, at zero degrees elevation, can be calculated very easily to within a minute fraction of a dB.
Obviously the telemetry system has to be completely EMI proof and the field strength meter must not be affected by the telemetry transmitter. I did use a system with a buried screened wire direct feed back to the shack, but it was obviously fixed and attracted some unwanted interest from the local inhabitants. I was always worried that somebody might take a fancy to the battery, or even the complete system!! The present system is installed in a vehicle, which can be parked up, locked up and left. This system is also much safer from a practical point of view, it was hard work setting up the system, carrying the batteries making sure they were charged up etc. etc.
It would obviously be very interesting to measure the field strength at various angles of elevation, but I have not got round to tethered dustbin liner bags filled with hydrogen yet! I have thought about it though, hydrogen can easily be generated under pressure from scrap aluminium and caustic soda. (Helium is for wimps!!)
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