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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment.

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Old 17th Jun 2012, 6:57 am   #41
trh01uk
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Default Re: NORWICH 1951 Transmitter found sealed in box

Sean,

referring to Pat Moore's history of amateur radio in the UK, I note he says:

"In November 1949 the GPO agreed to the use of 150 watts on all bands above 28 Mc/s (except 420-460 Mc/s)."

Thus implying that the 70cm band was available back in 1949 (and probably earlier than that too). He says the 2300MHz band was released in September 1946, so its possible that 70cms was around a great deal earlier.

My point was really that there was remarkably little activity at UHF back then - though no doubt it got going pretty quickly when items like this T.1951 hit the surplus market!


Richard
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Old 19th Jun 2012, 2:59 pm   #42
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Default Re: NORWICH 1951 Transmitter found sealed in box

Hi all,

What a wonderful discovery!

I suspect the circuit will be similar to this (AN/APT-2, 400-470MHz, 8W RF out 'Carpet II'):

http://www.nj7p.org/millist/sch/apt-2.gif

The transmitter is modulated with noise derived from a photomultiplier lit by an incandescent lamp (in the black cylinder at the back of the chassis) amplified by several tuned stages to give it the widest possible bandwidth, and choke-modulates the push-pull RF power oscillator.

A really good site dealing with the German radio and radars is Arthur O. Bauer's here.

Cheers
Alan
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Old 1st Feb 2013, 5:59 am   #43
Anthony Thomas
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Default Re: NORWICH 1951 Transmitter found sealed in box

The find of a lifetime, this equipment surely has kept well in its waxed cloth despite not having been looked after since the early 1950s

Tony
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Old 1st Feb 2013, 6:45 pm   #44
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Default Re: NORWICH 1951 Transmitter found sealed in box

Anthony,

It's actually surprising just how much stuff does turn up like this - still as new in its original packing. I have just been admiring a GEE receiver R3515 which is "as new" and in its original packing crate.

Often people bought them way back, put them away somewhere and just forgot about them. In some cases - literally - as in this instance.

Someone from New York emailed me a couple of years ago, having turned out his (deceased) uncle's flat. He found a WS19 brand new in its packing. I alerted various people over there that it had been found, and they might be interested in making an offer for it. I was very surprised to find that no-one in the USA I contacted was at all interested. Apparently they see far too many "WS19s new in their packing" to be bothered with yet another one!


Richard
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Old 1st Feb 2013, 8:41 pm   #45
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Default Re: NORWICH 1951 Transmitter found sealed in box

Richard

The trouble with such finds "over there" in the US would be one of costs freighting it over to the UK. The last few years I have come across and also been given some WWII equipment that should also be included in the many projects that people are working hard to recreate whilst the parts are available. I must take photos of some of the stuff I have and post on here, not planning to get rid of things just yet but one fine day it may be too late to send things to a worthy recipient that can make valuable use of these artifacts for want of a better word.

Back at the end of the 1970s when PW had the Purbeck oscilloscope project going I contacted A&H Supplies in the UK and purchased an ALA-6 Azimuth indicator for about £25 and started to strip this for my Purbeck project. Luckily I didn't get too far and still have all the parts I stripped off. I used a 3BP CRT with mumetal screen from a Loran aparatus that was scrapped. ALA-6 are hard to find these days I seem to think, there isn't much info on them at least.

Silent Key house clearances have now jolted my conscience to perhaps start sorting through and passing on things from my "spares box" that others are now looking for, I have seen with utter horror how much gets chucked into rubbish skips due to lack of knowledge.

Yesterday I looked through my hobby room and found the three RF24 units I have (thought they were RF25 but they are RF24) one in absolutely perfect condition and unmolested, one other is good but not excellent whilst one is incomplete and it came that way to me. Must take some photos

Tony
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Old 14th Oct 2015, 2:02 pm   #46
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Default Re: NORWICH 1951 Transmitter found sealed in box

I added some additional information to the APQ-9 web page at http://aafradio.org/countermeasures/APQ-9.html (including a system schematic that includes the PP-51/APQ-9 power supply.)

- Mike
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Old 24th Oct 2015, 7:59 pm   #47
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Default Re: NORWICH 1951 Transmitter found sealed in box

Reading this thread has prompted my memory. While I was was at School (1963), myself and a friend split the cost of an "Indicator unit type 10Q", bought in Hoe street Walthamstow. It seemed to be larger then the indicator units shown here, all IO valves and we thought it was of American manufacture, for air use (110V 400 HZ) PSU, we tried mains, it blew the fuse. It had a 3BPC1 CRT and a lovely little AFO which could be unplugged and slid out. The fixed frequencies (about 30 selected by a rotary switch) were selected by switching in little inductors. When I left School I had the tube, he the rest. I made several CROs re-using the same tube which I eventually sold in about 1975.
I wonder if any of you knowledgeable people could tell me what it was used for and its AFO?
Frank
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