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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 16th Sep 2019, 10:12 am   #1
llama
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Default Mystery A.M. transformer

This is the transformer in the mystery RF device I recently offered. It has Air Ministry markings that look like 10M/162 or possibly 10A/162. It has about 10.5mm of laminations and the markings on one side are IP and OP with what looks like an unused tapping. On the other side it is marked OS, T2 and IS. I suppose these are all input/output, primary/secondary (apart from the "T2" connection).

Overall size is 5cm lamination length, 3.8cm max winding width and 2.9cm height. Coloured dark brown varnish.

I wonder if, just out of curiosity and a sense of completion, anyone has the appropriate AP that would identify the characteristics of the transformer and/or the equipment it's likely to have come from. Speculation welcomed!
Graham
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Old 16th Sep 2019, 10:40 am   #2
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Default Re: Mystery A.M. transformer

Without checking, it sounds as if it might be one of the transformers from the A1134 intercom amplifier as used in the Lancaster bomber (like the one shown here about 2/3 down the page):

http://www.tibblestone.com/oldradios...adio/T1154.htm

If so, I'm afraid one or more of the windings is likely to be o/c.
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Old 16th Sep 2019, 11:13 am   #3
M0FYA Andy
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Default Re: Mystery A.M. transformer

More likely 10K/162.
This is shown in AP1086 as a Transformer Type 285, LF Output, overall ratio 1:2

Andy
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Old 16th Sep 2019, 11:45 am   #4
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Default Re: Mystery A.M. transformer

Would those need a beehive trimmer capacitor and what looks like an inductor with an adjustable core at bottom left?
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Old 16th Sep 2019, 11:52 am   #5
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Default Re: Mystery A.M. transformer

The chassis look like an electrickery backing box...

Lawrence.
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Old 16th Sep 2019, 12:17 pm   #6
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Default Re: Mystery A.M. transformer

It is: https://www.vintage-radio.net/forum/...d.php?t=159770
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Old 16th Sep 2019, 12:33 pm   #7
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Default Re: Mystery A.M. transformer

A 10K/162 transformer was used in the R1147 receiver.

Lawrence.
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Old 16th Sep 2019, 1:06 pm   #8
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Default Re: Mystery A.M. transformer

As a guess it might be for IFT alignment?

Lawrence.
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Old 16th Sep 2019, 1:06 pm   #9
M0FYA Andy
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Default Re: Mystery A.M. transformer

Quote:
Originally Posted by ms660 View Post
A 10K/162 transformer was used in the R1147 receiver.
Well spotted!

Andy
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Old 16th Sep 2019, 1:09 pm   #10
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Default Re: Mystery A.M. transformer

Thanks to a Radio Constructor archive.

Lawrence.
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Old 16th Sep 2019, 1:17 pm   #11
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Default Re: Mystery A.M. transformer

Ah I see, a transformer re-used for a spot of home brew. Sorry I took a while to catch on.
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Old 17th Oct 2019, 6:09 pm   #12
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Default Re: Mystery A.M. transformer

Thanks for device this is the circuit and valve line up pin numbers match resistor at top ht to anode is 56k
any one a clue as to where the green and the green/red wire would go also ideas on what it is ? thanks Mick
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Old 17th Oct 2019, 6:28 pm   #13
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Default Re: Mystery A.M. transformer

If the green wire is connected to the red/green wire, the double-triode becomes a "cathode-coupled oscillator" whose frequency is determined by the coil and capacitor.
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Old 19th Oct 2019, 12:36 pm   #14
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Default Re: Mystery A.M. transformer

Hi thanks connected green to red green fitted ECC81 6v+200v ht and got a carrier on 1.45 mhz . the other stage i would think is a af osc ? (does not work) caps way off value/oc so transformer is used as a modulation transformer. i would think this is an alignment aid or a marker osc. Will recap and retest Mick
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Old 19th Oct 2019, 1:02 pm   #15
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Default Re: Mystery A.M. transformer

Yes the other stage is an audio oscillator - like you said it's set up to tone-modulate the RF-oscillator, so your 'thing' is indeed probably an alignment-aid/test-signal-source for the medium-wave band.
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Old 19th Oct 2019, 4:49 pm   #16
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Default Re: Mystery A.M. transformer

Quote:
Originally Posted by mickm3for View Post
Hi thanks connected green to red green fitted ECC81 6v+200v ht and got a carrier on 1.45 mhz . the other stage i would think is a af osc ? (does not work) caps way off value/oc so transformer is used as a modulation transformer. i would think this is an alignment aid or a marker osc. Will recap and retest Mick
Or maybe a "pantry" transmitter so you can play recorded music or programmes onto a vintage RX?

73

Roger

Last edited by G3VKM_Roger; 19th Oct 2019 at 4:52 pm. Reason: spelling
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