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ZL1ABS > ALL      02.08.21 11:26l 137 Lines 23257 Bytes #999 (0) @ WW
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Subj: Martin the Wireless ZL1UC Looks back into History
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From: ZL1ABS@ZL2BAU.#79.NZL.AUNZ
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"Martin the Wireless" Looks back.
Harry G. Martin ZL1UC

Part 1

My first introduction to wireless was in 1922 when I was living in Newcastle
on Tyne and the BBC opened a station there with the callsign 5NO.
My first lesson went like this -"Well you see 5NO transmits on 520 metres and
to receive it you need 520 metres of wire (wireless?). Of course you
can't put 520 metres of wire out in your backyard, so you put as
much as you can outside and the rest you wind in a coil inside
(usually on a 5 inch former)". With the addition of a condenser, a crystal
detector and a pair of headphones you had your receiver.
To get exactly the right length of wire, the coil was provided with a brass
contact which could slide up and down the coil. This was the "tuning".
The condenser was fixed, but no one told me what it was for until much later.
The detector was a chunk of galena crystal screwed into a small metal cup, the
other contact being a springy piece of wire (catswisker) with which you
prodded the crystal until you found a sensitive spot, whereupon the music came
forth. Very exciting. Of course if anyone sneezed or walked heavily across the
room, the catswisker jumped off and you had to start all over again.
Selectivity as we know it now was absent, but was hardly as problem as the
only other station anywhere near was Cullercosts Radio GCC which worked
shipping in the North Sea and used a spark transmitter on 600 metres.
(Sparkies have to be heard to be believed - worse than any "Woodpecker").

These crystal sets could be made for a few shillings, except for the headphones which were fairly expensive. Some sets used variometer tuning, that is with one coil rotating inside another. In one position the coils aided each other to cover the longer wavelengths, rotated 180 degrees they opposed each other and received the shorter wavelengths. The condenser was still fixed.

 Then at the age of 12 my family moved to Hastings on the South coast and as the nearest broadcast station was London a crystal set wasn't too good. I was lucky enough to have a schoolmaster who was interested in wireless and he commissioned a P.O. Engineer to make us a receiver. (Amazing the number of P.O. components I recognised when I joined the P.O.) This was housed in a cabinet about a yard cube and needed a huge heavy car battery to heat the three valves. These needed 1 Ampere at 4 Volts, the excess from the car battery being absorbed (wasted) in filament rheostats. This was the recognised method of volume control in those days. It had plug in basket coils, swinging coil aerial coupling and reaction, and, miracles of miracles, we could receive Eiffel Tower and later one or two continental stations as well as 2LO.  I was thrilled to be elected chief wireless operator until I discovered that part of my duties was to carry the car battery down to the nearest garage about a mile away once a fortnight and bring back the replacement. No transport and it took two of us to carry it. I can remember the excitement when we bough our first “dull emitterö valve - 37/6 it cost, which was a lot of money in those days. The extra HF stage meant another set of basket coils with 12 inch extension handles on the swinging ones to avoid hand capacity effects, so tuning became really arduous.

At home I plodded through a succession of one valve (with variable grid leak!), two valve and three valve sets and even a five valve superhet with frame aerial and plug in I.F. coils. Can you remember the “Cossor Melody Makerö, the “Mullard Master Threeö and Scott Taggart's “Super 60ö?

Those were the days when one made up ones' own variable condensers - so many fixed plates, one less moving plates, hundreds of spacing collets, lengths of screwed rod, and cut out suitable pieces of ebonite sheet for the end plates. As I said, “those were the daysö.

Obviously when I left school I wanted to be a Wireless Engineer but the only such firm in Hastings wanted a higher apprenticeship premium than my parents could afford and a wage of only five shillings a week. So when I heard at a night school prize-giving that the Post Office Engineering Dept. accepted youths without premium and at much higher wage of 12/6 a week, I put my name down at once. After two years of pedalling round the town on a P.O. red bike as a boy messenger, I took the entrance exam to higher things only to find to my horror that I had passed too high to be an engineer and was appointed as a sorting Clerk and Telegraphist at 19/6 a week. Upon my protest that I wanted to be an engineer, our inspector sneaked around to my Mother and told her that I should be digging up roads for two years and this so shocked her that with pressure from home & work I accepted the SC & T post.
Telegraphs wouldn't be so bad I thought (courage you brass pounders - Morse course was 4 hours a day for 3 months to achieve 20 wpm). But redundancy was on its way.
In three years our instrument room dwindled from twelve Morse circuits and two Baudot printers to just two teleprinters. As the females couldn't at that timework in the sorting office, it was the male telegraphists who were kicked out of the instrument room. I hated the sorting office and when I saw an advert for the P.O. Ship/Shore wireless service I applied at once.

After a particularly filthy morning (5AM - 1PM) parcel sorting, without any prior warning I was told to report to the Postmaster's room to be interviewed for the W/T post. My feelings can be imagined as bleary-eyed & dirty, I faced my interviewer, but I answered his questions more or less satisfactorily and passed his Morse test at 20 WPM. He turned to the Postmaster and said, “When could you release Mr Martin?ö The PM's reply - “You can take him now if you want toö was hardly the best recommendation, but within a month I was on my way to Fishguard Radio in South Wales. There I became “Martin the Wirelessö, along with “Evans the postö and “Jones the Breadö.

Before we were “certifiedö we had to pass a Morse test at 27 WPM, pass a theory exam to 1st class PMG standard and get our elementary certificate in French and German. The two latter proved to be of little use, however, as most French and German operators spoke better English than we did, and anyway we had the interlingual cipher books which did away with the necessity for any language. For theory our bible was the “Admiralty Handbook of Wireless Telegraphyö which at that time still spoke of “Micsö (microhenries) and “Jarsö (the capacity of a standard Leyden jar = 0.0011 mfd).

Part 2
“Martin the Wirelessö was my title when I was a Post Office wireless operator in the small Welsh village of Goodwick, Pembrokeshire in 1932, where half of the population was named Davies, Evans or Jones and some descriptive addition was essential, such as Evans the Post or Jones the Bread. So our crew were known as So and So the Wireless.

Fishguard Radio GRL was set on a cliff top on the Goodwick side of Fishguard Harbour. Down below was the Great Western rail terminal from which departed the ferry steamers for Ireland. Our service area was the South Irish Sea and the Bristol Channel, although when conditions were right we could work as far as Icelandic waters when nearer stations, Wick or Portpatrick Radios could not. (Introduction to Skip?)

Our main duties were (1) Distress watch - “SOS'sö (2) Medical and other urgent assistance when required, (3) telegrams to and from ships (4) collecting and sending to Lloyds by landline information on ship's movements.
Under (1) we would co-operate with Coastguards, lifeboat, ocean-going tugs and other nearby vessels. These latter could be alerted, if off watch, by an Auto alarm system that accepted a pre-arranged Morse signal and rang an alarm in the W/T office.
Under (2) ships would often ask for medical advice if there were illness on board and no doctor. We would pass the message to our local Doctor or Hospital who would prescribe. A serious accident might mean diversion of another ship with Doctor to go to assist.

Language was no difficulty as every ship and shore station held a cipher book in its' own language.
Under (4) Lloyds compile a daily list of positions of every registered ship in the world, where been, where going, expected E.T.A. etc. Incidentally Lloyds and the tug companies used to send us a Christmas box of cigars or tobacco as a reward - or to keep us sweet.

Our power supply was from the Harbour generators at 400 Volts DC that made it necessary to run motor/alternators to give us the various voltages required. When the harbour cranes were unloading the ships, those voltages went up and down like yo-yos. One of our M/As was a rouge, now and again it used to take off suddenly and increase its' speed to screaming point until we had to switch it off before it spun out of its' bearings. The output was the usual 220 Volts at 400 cycles and this gave us our distinctive 800 cycles ICW note when rectified but not smoothed. When the M/A took the bit in its' teeth that note became almost supersonic. No one could ever discover the reason for this roguery.

I was just too late to see the spark transmitter, which was originally at GRL, but was told that it could be heard over most of the village. Some ships still had spark transmitters with crystal receivers at that stage.

Our main transmitter was rated at one and a half kilowatts and was housed in a cage about 8 feet square. It was very simple, being only a one-triode valve Hartley oscillator with 11,000 Volts on the anode. Inside the cage were the oscillator valve with its' filament transformer; two rectifier valves with their filament transformer; the HT transformer; an oil filled condenser for smoothing the HT if CW was required (very seldom as many receivers could not then resolve CW); an air-spaced fixed condenser and tuning coils of half inch copper tube. These last, by the way, were dutifully polished until they shone, as a nicely polished coil was reckoned to be more efficient than a tarnished one. Tuning was by variometer and we tuned for maximum aerial amperes without running the valve too hot. A dull, red glow on the anode was quite acceptable. No comic business with SWR meters!

 As for keying, believe it or not, the key was in the primary circuit of the HT transformer and broke 10 Amps at 220 Volts.  Little wonder the key was totally enclosed in an earthed metal case. No relays anywhere. The aerial came right into the room and everything metal had to be earthed. If one was unwary enough to touch the DF gear while sending, one was assured of a nice RF burn which turned the skin of the fingers into a white powder and smelt like burning toast.

The main aerial was 120 feet high and 200 feet long. We used wavelengths of 600 metres for calling, 705 & 800 metres for traffic.

The main receiver was a real antique. The station had been opened in 1920 and the receiver was the original. Some of the valves were original too. It was a Marconi BT 12A with six HF stages; Detector and two LF valves; all triode types; DER & DEQ; the sort with a pip at each end and one on each side. All bright emitters, so that at night one scarcely needed any other illumination. It was a marvellous set though, background noise was zero, yet during darkness we could often hear the American coast stations WAG, WSC etc on 600 metres. Despite this sensitivity, when ships came into the harbour below, their signals did not blast our eardrums. This was due to the limiting effect of the valves, none of which could handle more than a fraction of a milliwatt, but could amplify well enough. The HF stages were coupled with untuned HF transformers wound with Eureka wire so that their selectivity (?) covered the whole shipping band from 600 to 800 metres. Much later a Superhet unit with AGC and a BFO was fitted in place of the HF panel, but while selectivity was improved, the background noise was terrible.
A goniometer was fitted for DF work, Bellini Tosi style, but it was not calibrated accurately and we used it only for cutting out interference. The DF aerial loops were 90 feet high.

 
For short distance work, mostly trawlers and some coastal vessels, we used 149 and 220 metres. The set up here was more modern. The transmitter was a Marconi ship set nominally 200 Watts, in size about 2 feet by 3 feet by 1 foot. Four 50 Watt triodes - two in parallel as the oscillator and two in parallel as the modulator. For ICW all four were switched in parallel, but in fact we used to get almost as much power from one valve alone. The microphone was an ordinary P.O. carbon type and we found we had to build a pre-amp to get anything like enough modulation.

The trawler receiver was merely an HF - Detector - LF set, again with a goniometer. The latter was never used for the simple reason that RF from the main transmitter had long ago burnt out the windings till the rotating coil was like a hedgehog with bits of wire sticking out all around and sounded like a child's' musical box when rotated.

Both receivers were battery operated with a 6 Volt 200AH accumulator for the 4 Volt filaments. Filament rheostats were fitted and often used as volume controls. HT supply was from 120 Volt accumulator, 50 AH. A further 80 Volt 50 AH accumulator served the Morse landline to the nearest main P.O. All batteries were duplicated and had to be charged in turn every few days. The Westinghouse rectifiers for charging occupied a space about 6 feet by 4 feet by 3 feet. You will see that I have used the nomenclature in use at the time.

It was a happy life there; traffic was light (too light actually as the station closed later as being uneconomic) our hours were conveniently arranged and the countryside very pleasant. As much bathing as one could wish for down by the harbour and “the natives were friendlyö.

My next posting to the worldwide Burnham/Portishead Radio was not so happy - hours much worse; much more work and the continual lambast of noise - atmospheric especially on 2100 metres, made life a literal headache.

Part 3

To Portishead/Burnham Radio (Being my unofficial and possibly inefficient memories of the period 1934 to 1939).

When Fishguard Radio was closed as being uneconomic I was transferred to Burnham Radio and my interest in short wave radio began from that date. This was the main British radio station for communication with ships at sea all over the world. Most communication was in CW on “Long Wavesö of 2400, 2100 and 2013 metres, also on “Short Wavesö on 18, 24 and 36 metres. The transmitters were at Portishead and the receivers were at Burnham-on-sea, 19 miles apart so that we could work several ships at once on the same waveband without interference to each other. Beside each receiver at Burnham was a control panel by which operators could choose any of the transmitters at Portishead.

As we operators were stationed at Burnham, I can really only describe the receivers there. Although we used to visit Portishead occasionally on a social basis, the place seemed to us to be a complete jumble with transmitters standing on top of others with barely room to walk between them. Most transmitters were around the 6 kilowatt mark.

There were four long wave receivers, one for “searchö on 2100 meters, one on 2013 metres, one on 2400 metres and one standby. They were heterodyne receivers (Not superhets) and had two main tuning controls, one “Tuneö and one “Hetö. The four H.F. amplifiers and the push-pull demodulator could be individually tuned, but with a “Heath Robinsonö arrangement of pulley wheels and catgut they could be tuned together by the main tune knob. The Het knob tuned a separate beat oscillator near the received frequency. These sets were almost exclusively used on the North Atlantic shipping which at the time was in its' heyday of transatlantic liners.  They kept us very busy and if ever the Reykjavik or Thorshaven cables broke down we used to take their traffic as well. These two latter normally sent Morse on a Wheatstone machine at 100-200 wpm and they could never slow down to much less than 40 wpm, so we used to put two operators on - what one missed the other hopefully go! Great fun. The continuous atmospheric noise at 2100 metres was simply terrible and one could not usually stand it for more than one hour, so operators were “rotatedö on short wave, landline teleprinters or clerical work. The sets had no A.G.C. or noise limiters but we used to find some relief by plugging in a 2 mfd condenser into the spare phone jack as a deadener - actually quite effective for C.W. work using H.R. phones. I don't suppose it would work with the low impedance phones now in common use.

The short Wave section was a joy to work in if you were interested in technicalities as distinct from working ships. Being a comparatively new service we used to have receivers on loan from various companies to try them out and the section was therefore largely experimental. Later on of course things became more standardised and (Marconi) CR 150s were fitted throughout. At the time of which I am writing, however, we had a collection of prototype receivers from Marconi, GEC etc. and even an old Atwater Kent. Most of these sets were “straightö, HF - Detector - LF stages.  Many ships used I.C.W. but if C.W. was used we just increased reaction until the set self-oscillated. Some had separate tuning for each stage, but this wasn't as bad as it sounds because the shipping bands were quite narrow and each stage kept more or less in tune and only needed peaking up when a ship was heard on tuning only the detector stage. The aerial could be plugged into the detector stage only, or into as many HF stages (usually four) as one needed to achieve more gain or selectivity. Of course more gain meant more background noise, but these straight sets usually had a much better signal to noise ratio than superhets, which were at the time quite rare.  
To set up after changing bands one merely had to key the transmitter at Portishead and tune all stages on that. Thereafter only a touch was necessary to bring in the ship (Selectivity was hardly knife-edge in those days).

Then came the great day when our “P.O. Quick Searchö receiver was installed. This was a masterpiece of engineering occupying four six feet tall by twenty-two inches equipment racks. It was a double Superhet using twenty-seven valves, but all tuning was done with one knob driving the first beat oscillator. A second knob was provided tuning the first mixer, but this was used only for peaking up. The first IF was 30 megacycles, chosen as we were told because there was little or no activity on that frequency (where were the Amateurs then?). Every stage that could be was in push-pull with HF 610 or SG 610 valves, which had pins at each end that laid horizontally and fitted through holes in the screens. Every valve was wired back to the end panel, which was confined entirely to testing and switching. Test was done daily and any valve under 70% emission was changed. A rotary switch was fitted above the panels to give a choice of eight different aerials. Changing bands was done with a plug-in coil, would with quarter inch copper tubing!

 In contrast to this colossus we were once loaned a battery operated Eddystone “All World Fourö an HF - Det -LF model with plug-in coils and using reaction to receive C.W. We liked this so much - it's outstanding feature was the almost complete lack of background noise - that five were ordered and proved themselves, dare I say it, more popular than the “P.O. Quick searchö.  Though L.T. requirements were met by a central secondary battery, H.T. was at first supplied from individual dry H.T. batteries under the tables, which gave the place a rather untidy look. These were later centralised when inter-set interference problems were ironed out.

As for our aerials - hams would class them as an aerial farm. Five 150 foot masts supported arrays of multiple dipoles, some horizontal pointing to the most used shipping areas and some vertical for omnidirectional searching. For 18 metres a large rotary array, which ran on a circular railway, it needed a five horsepower motor to drive it and could be controlled from the panels beside each receiver.  At first these aerials were all led into to the building by 600 Ohm open wire feeders, right down to the receivers, each receiver having a choice of four selected by wander plugs. As you can imagine the place was a festoon of wires. 
Later on a system of coaxial feeders was introduced. All led to sockets on a central switchboard. Each receiver then had four co-ax leads with which one could go to the board and select any four aerials that suited the working frequency at the time. Needless to say, this tidied up the room considerably but I'm afraid efficiency suffered. With the open wire feeders we often got better results when one plug was in a leg of one dipole and the other plug into another dipole. So much for theory and practice.

After I left the station was completely remodelled and huge rhombic aerials were erected, fortunately we had acres of room. What happened after 1939 is unfortunately classified, but can you imagine what a row of thirty HRO receivers, rack mounted and each with a Morse tape recorder alongside might look like?

Typed by Michael ZL1ABS 14 April 2008
[Harry Martin ZL1UC SK was my Morse Code Tutor back in the 1980s.He had immigrated to Auckland, New Zealand with his wife after retirement. His three part memoires were printed in the local NZART inc. Branch 29 magazine around that time.  Recently I found these paper copies and decided that they might make interesting reading on Packet Radio and are worthy for preserving electronically.]


Harry Martin ZL1UC (I don't recall what his G callsign was) didn't write
about his WW2 efforts, claiming they were "Officially Secret". Maybe the
secrets expire after 50 years?
But alas Harry is no longer alive to pass on his further memories. I don't
think he left any "sealed envelopes" with anyone.
He was a very British gentleman & practically never went anywhere unless
dressed in a suit. He even had a "gardening suit". He drove a "Mini" with
cloth covered seats.
I do remember he had a part time retirement job in ZL demonstrating power
tools in shopping malls. He was an active club member of the North Shore
Branch 29 of NZART inc, often doing jobs on the building the club owned
back in those days. There used to be regular Saturday morning open days &
training classes for the Amateur examinations. That was when most shops
were required to be closed for the weekend, by law.
Now that everything is open practically every day of the year, it's hard
to get a Saturday meeting of Amateurs together. 

His wife began to have serious health problems, but Harry died first in
the end. I was still a lad in school at the time or might have just joined
up the New Zealand Post Office Telecom branch as a trainee Telephone
Technician (December 12 - 1977 I recall).

I'm pleased that one or two Amateurs are interested in the tales of
"Martin the Wireless". It makes it worth my time typing the text from the
1981 copies of the local club magazine.

73 - Michael, ZL1ABS @ ZL1AB




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