NORWICH 1951 Transmitter found sealed in box

[AC/HL]

What would the average "irk" do when the item was needed in service?
The packaging is designed for this, and the equipment would survive this.
Just open it.

[dseymo1]

Is 1951 the date of manufacture?
To my reading, it's when the dessicant was last renewed, which may well have been later.

[trh01uk]

The 1951 date is for "the last charge". Odd words those, which I don't understand. I suspect its to do with packing and checking the item - almost certainly nothing to do with its manufacture. Particularly as these equipments were made in the USA anyway!

When it finally emerges from its packing it should be in pristine condition.....


Richard

[geeoboeh2s]

Richard

If this unit was used post war it may have been in a training role.
In which case restricting the highest frequency to 485 MHz was probably to avoid unintentional interefence to other "friendly" users. Safer to physically restrict it than to rely on operator control.

I have a P58 search receiver (vintage 1944/5), that includes the above frequencies, reconditioned by Plessey for the Admiralty in 1959, almost certainly for training purposes.
WW II equipment still had its uses up to the 1960's.

Chris

[trh01uk]

Chris,

yes, that sounds very sensible.

Incidentally, based on my experience in the CCF in 1971 to 74, WWII equipment was very much still in use well into the 70s. We had WS88s, WS31s, WS19, R107, WS62, all running with original batteries, and serviced by an Army technician who called into our school in a truck full of test equipment. I know that the equipment got sold off eventually sometime in 1975, mainly because the school was being turned into a 6th Form College, and the new head didn't believe in nasty activities with guns, uniforms, etc.


Richard

[G6Tanuki]

Yes, that was commonplace. In the mid-1970s I was Sgt.Sigs in my school CCF: we had 31/88-sets, an 88AFV, lots of B44s, several 62-sets, A40/A41s, and a brace of C12s operating on the National Radio Net (5.mumble MHz). I recall 'acquiring' [via a chat with the QM at COD Donnington] about fifteen of the big metal-cased 110AH 12-volt batteries - then freaking out the chemistry lab-technician when I said I needed several gallons of H2SO4 to fill them.

A C12 into something like 500-feet of wire puts out rather a potent signal !

G6Tanuki.

[n_r_muir]

Hi, If it is part of the Carpet equipment for jamming the German Wutzburg Radar then it might look like the unit shown in this link

http://www.tubecollector.org/equipment/8012-radar.htm


Ross

[geeoboeh2s]

Richard

I should have added in my last report that around the mid 1980s I went on an official visit to 360 sqdn, the EW training unit, at RAF Wyton. We saw the equipment fitted to their Canberra aircraft that were used in the Thursday War and at EW Training ground at Spadeadam.
Apart from a Tektronix spectrum analyser the other equipment was valved and looked of WW II origin.
Unfortunately I don't remember any type numbers.
I also seem to recollect an article in Radcom some years ago by an ex 360 sqdn member who was a radio amateur and I am wondering whether that may provide further information.

Chris

[G3VKM_Roger]

Originally Posted by geeoboeh2s

If this unit was used post war it may have been in a training role.

It's also probable that the equipment was put into storage after the last desiccant change because there was real concern that it might be needed again, maybe not to jam Wurzburgs but Sino-Soviet transmissions. In 1951-3 the UK amateur radio magazines carried frequent wanted adverts for American equipment, from BC-221s, ET4336 and APN/4s, up to microwave test gear and it's probably that these commercial buyers were feeding the Korean War effort and repatriating the equipment.

Could be that both US and UK had disposed of their war surpluses too quickly and were now regretting it, so even gear that was obsolete was put into store "just in case"?

Roger/G3VKM

[mercede5]

Heres the final piece in the jigsaw - looks like a number of you were on the money.
additional info
label inside
Mc Michael radio Ltd (see image)

Transmitter has a metal plate (top left) on it
Signal Corps
Radar Transmitter T-39/APQ-9
serial No 451 Order No 868-Day-44
Hudson American Corporation
80-115v 1(symbol O with a vertical line through it) 400-2600~24 V.D.C

Another metal plate (top centre)
transmitter T39/APQ9
T1951 WD Symbol (Arrow pointing up) 10D18253

If you need anymore images (close-ups etc) just let me know. Can only post 5 at a time so here they are

Many thanks for your assistance- it has been great.

[Nickthedentist]

Goodness, it really is mint, in spite of the desiccant being slightly past its use-by date!

[HamishBoxer]

That would be the condition I would expect. I like what looks like two 807s in the final RF stage.

[Sean Williams]

Nope, the 807s are the modulator, it uses an 8012 as the RF output valve

[trh01uk]

Originally Posted by Sean Williams

Nope, the 807s are the modulator, it uses an 8012 as the RF output valve

Sean,

you don't have a copy of the manual for this kit do you? I had some photos (from Mike Dean) of Phil Judkins extremely poor copy - from which I managed to extract a circuit diagram (just!). A decent copy would be nice. I can get a decent scan from Phil's - but its a long way to his house!


Richard

[Sean Williams]

Sadly not Richard.

I will probably be seeing Phil soon, assuming he has the time I could ask him to loan me the manual and then scan the diagram for you?

Sean

[trh01uk]

Sean,

well, if you think you can get the manual from Phil that would be great - thanks a lot. He won't loan the manual to Tony and I - but he said he would be happy for me to scan it next time I am visiting. Trouble is that I don't make the trip that far north too often!

Richard

[G6Tanuki]

Originally Posted by Sean Williams

Nope, the 807s are the modulator, it uses an 8012 as the RF output valve

Given the frequency-coverage of the RF part of this beastie, I'm wondering if it might have been adaptable to the 420-450MHz Amateur-band? That could perhaps explain why such gear was being sold off and bought by radio-engineer types.

--G6Tanuki

[trh01uk]

I rather think that 1951 was a bit early for most people to be interested in the 70cm band, given that only 10 years earlier there were only a few people on 56MHz, and the highest band (112MHz) was seen as really esoteric.....

Sadly, I think most surplus equipment was sold off as a handy source of components. Not much of it could be easily converted into something useful, so most of it ended up as a source of top quality resistors, capacitors, etc. Of course, some items were useful - such as WS19s, and GEE displays to make TVs.


Richard

[HamishBoxer]

This great that this has been found in mint condition.

[Sean Williams]

I have some US based amateur books that refer to 420Mc operation, these date around 1949 through to 1953.

Admittedly this was all quite experimental, and the UK may well have been somewhat behind the times given our circumstances at that time.

Sean