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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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5th Mar 2021, 11:38 am | #1 |
Nonode
Join Date: Jun 2009
Location: Herefordshire, UK.
Posts: 2,495
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A possible PYE 45 Mc/s radar IF strip
I've a possible PYE If strip - somewhat modified by others; home-built TV? I've tried looking for circuit diagram information on what it might have originally been.
It has an identity number painted on it 10DB/84.65, and comprises 5 VR91's and what was, but is no longer present, a small valve diode detector. The best I've achieved so far is a Practical Television article, March 1952, Page 436. However the info there is incomplete. The article talks about an R.A.F. unit no. 153. Ideally I'd like the original circuit diagram and knowledge on how it was originally controlled in terms of voltages and signals applied to it. Can anybody point me in the right direction? I know that these valves were extensively used in Second World War Radars and that there were IF strips of differing types that used them. |
5th Mar 2021, 10:50 pm | #2 |
Nonode
Join Date: May 2007
Location: Preston, Lancashire, UK.
Posts: 2,511
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Re: A possible PYE 45 Mc/s radar IF strip
Receiving Unit Type 153 has Stores Reference Number 10DB/6097, your unit with Ref No 10DB/8465 is a Receiving Unit Type 153A.
I'm trying to ascertain the difference, probably not very much. Andy |
6th Mar 2021, 12:11 pm | #3 |
Nonode
Join Date: May 2007
Location: Preston, Lancashire, UK.
Posts: 2,511
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Re: A possible PYE 45 Mc/s radar IF strip
Here is the circuit of the Receiving Unit Type 153, I'm still looking for information on the Type 153A but I'll be surprised if there is much change.
I'd be very interested in some photos of your unit, please, including the Stores Reference Number. Andy |
6th Mar 2021, 12:47 pm | #4 |
Nonode
Join Date: May 2007
Location: Preston, Lancashire, UK.
Posts: 2,511
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Re: A possible PYE 45 Mc/s radar IF strip
OK, here is the circuit of the 153A. Used in H2S MkIVA.
andy |
6th Mar 2021, 12:48 pm | #5 |
Rest in Peace
Join Date: Mar 2010
Location: Berkshire, UK.
Posts: 72
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Re: A possible PYE 45 Mc/s radar IF strip
Receiving unit type 153 led to a number of very similar units used by all three armed services and with different part numbers and stores numbers. Some had very minor differences but were still allocated a different part number even if only from a different manufacturer.
You say that yours has 5 VR91s and is missing the VR92 diode. The five VR91s are the bandpass ampifier stages. There should also be a sixth VR91 the other side of the VR92 cover. This is a video amplifier. You made no reference to a further mssing valve so has the socket been removed. Andy has requested a picture that should help with identification. Chris |
6th Mar 2021, 2:33 pm | #6 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
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Re: A possible PYE 45 Mc/s radar IF strip
Yes, the 45mc/s IF strips were used in homemade 50's television. Very often with a green CRT.
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6th Mar 2021, 6:38 pm | #7 |
Nonode
Join Date: Jun 2009
Location: Herefordshire, UK.
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Re: A possible PYE 45 Mc/s radar IF strip
Here are some 'photos as requested.
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7th Mar 2021, 11:32 am | #8 |
Nonode
Join Date: May 2007
Location: Preston, Lancashire, UK.
Posts: 2,511
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Re: A possible PYE 45 Mc/s radar IF strip
Is there evidence that the chassis has been shortened at the right-hand end in your first picture?
Andy |
7th Mar 2021, 11:50 am | #9 |
Nonode
Join Date: Jun 2009
Location: Herefordshire, UK.
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Re: A possible PYE 45 Mc/s radar IF strip
I've attached a photo of the end, where on very close examination I reckon the final VR91 stage has been cut off. Who ever did it did quite a good job. The modifications that I've discovered so far are:
1) The two input Pye connectors replaced by a single Belling & Lee Socket; 2) The original 8 pin Jones plug replaced with a 6 pin Jones plug. This only uses 5 out of the six pins; 3) The removal of the original pin 5, 6 circuitry and its replacement with a -5 volt line derived from the heater circuit; 4) The replacement of the VR92 valve diode in the little shielded box with a semiconductor diode. By the way, the modifications list on the box has no entries. So all in all, a little hacked about... |
8th Mar 2021, 6:30 pm | #10 |
Nonode
Join Date: Jun 2009
Location: Herefordshire, UK.
Posts: 2,495
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Re: A possible PYE 45 Mc/s radar IF strip
An update:
The input circuitry has been slightly modified; the 82 and 270 Ohm resistors have been removed. The output circuit is simply the output end of L16 (see the 153A .pdf above). A correction to item no.5 of my list above, the voltage should read -1.5 Volts. Anyway, it works. I can receive the pulses of an Ionospheric Radar system which operates on 46.4 Mc/s. Rather appropriate, a radar IF strip receiving radar signals... Thank you MOFYA_Andy for your help. |
9th Mar 2021, 12:39 pm | #11 | |
Nonode
Join Date: Dec 2012
Location: Stockport, Greater Manchester, UK.
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Re: A possible PYE 45 Mc/s radar IF strip
Quote:
My friend in Germany reckons that would be the Belgian BRAMS radar, Yper & Dourbes on 49.97, 150W brams.aeronomy.be He once heard 46.3MHz, radar PRF=25 Hz, with tone beep, Es dir=East
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9th Mar 2021, 12:55 pm | #12 |
Nonode
Join Date: Dec 2012
Location: Stockport, Greater Manchester, UK.
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Re: A possible PYE 45 Mc/s radar IF strip
Sorry, having looked through the BRAMS pages I see that it is a CW system, which leaves an interesting question about the pulsed emissions. He only once heard pulses on 46.3, radar PRF=25 Hz, with tone beep, dir=East during Sporadic E conditions, which certainly have not occurred this week.
My friend has one of the best all-band receiving installations in Europe but says he has never heard anything of the HAARP High-frequency_Active_Auroral_Research_Program from Alaska, which uses 49MHz among others. dx.3sdesign.de/ I think you must have a local source
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9th Mar 2021, 7:17 pm | #13 |
Nonode
Join Date: Jun 2009
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Re: A possible PYE 45 Mc/s radar IF strip
Julesomega,
I would not be surprised if it was localish - it is strong. I've received it on Band I DX TV, just below the old channel E2 vision frequency, for a few years now. I re-confirmed the 46.4 Mc/s frequency with a separate radio today. It is not CW, rather a sequence pattern of regular pulses with non regular ones. |