|
Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
|
Thread Tools |
20th Sep 2020, 8:53 am | #1 |
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,654
|
Anyone recognise this naval equipment?
I picked up the attached photos of this "Amplifier A/S 31" on a facebook post recently - a piece of naval equipment I've not seen before. I think there are some intriguing elements to the schematic - but I will let others comment before pointing them out.
Obviously Collingwood might well say exactly what it was for, and what equipment it was part of - and I have recommended the owner gets in touch with them. Richard |
20th Sep 2020, 2:09 pm | #2 |
Nonode
Join Date: May 2007
Location: Preston, Lancashire, UK.
Posts: 2,511
|
Re: Anyone recognise this naval equipment?
Richard,
I wonder what 'A/S' means? I have an odd Admiralty unit, Receiver A/S 324, which I'm struggling to find anything on. Dated 1944, a rather anonymous steel box, it looks to be a VLF TRF receiver. Searching the Collingwood website, which I find to be very unfriendly, doesn't throw up 'A/S'. Andy |
20th Sep 2020, 2:31 pm | #3 |
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,654
|
Re: Anyone recognise this naval equipment?
Andy,
well, fully agreed on the unfriendliness of the Collingwood website. Its got an absolute mine of information in it - but finding anything specific is a total nightmare. I have had a good rummage but failed to turn up anything with the prefix "A/S". Plenty of other amplifiers of course. Looking elsewhere on the web does suggest that "A/S" might stand for "anti-submarine". An example of that is given here: https://en.wikipedia.org/wiki/Loch-class_frigate I've analysed the circuit to some extent, and I believe it to be a TRF receiver, with a heterodyne oscillator mixing in a semiconductor rectifier, followed by a couple of audio stages. Looking at the tuned circuits, the capacitor values are suggestive - given that the variable is 7nF (!!! - how big is that brute??) and you can switch in up to 3 more 6nF capacitors. So we have a total of some 25nF. So the frequency range is probably down to 13kHz or so. And that would be typical of submarines, which I understand can transmit submerged on such extremely long wavelengths. That would mean the figures on the dials - which I can't read (too blurry) are probably in kHz). Further clues are that there is only one RF stage, but in front of it is a hefty resistive attenuator. If a submarine was close - the field strength from a powerful transmitter might be extremely high. And if it wasn't close I presume the ship wouldn't be that interested..... Richard |
20th Sep 2020, 3:01 pm | #4 |
Octode
Join Date: Mar 2011
Location: Sheffield, South Yorkshire, UK.
Posts: 1,453
|
Re: Anyone recognise this naval equipment?
No idea what it is but agree that A/S is most likely Anti-Submarine.
|
20th Sep 2020, 3:15 pm | #5 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
|
Re: Anyone recognise this naval equipment?
What's the Admiralty Pattern number?
Lawrence. |
20th Sep 2020, 3:36 pm | #6 |
Heptode
Join Date: Apr 2010
Location: West Midlands, UK.
Posts: 663
|
Re: Anyone recognise this naval equipment?
Could it be something to do with ASDIC, the frequencies seem to be similar.
|
20th Sep 2020, 3:41 pm | #7 |
Heptode
Join Date: Dec 2014
Location: Lincoln, Lincolnshire, UK.
Posts: 583
|
Re: Anyone recognise this naval equipment?
I would agree. A/s is accepted as anti submarine and because of the frequency it could be sonar but the only circuitry I have to hand is American.
|
20th Sep 2020, 4:12 pm | #8 |
Dekatron
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,603
|
Re: Anyone recognise this naval equipment?
Way back for a long time I worked on Naval Sonar systems, a few of the very old ones were designated A/S xxx for Anti Submarine.
Never come across A/S 31 though, a wild guess is that it is pre 1950. David |
20th Sep 2020, 5:01 pm | #9 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,935
|
Re: Anyone recognise this naval equipment?
These are 1930,s 2 volt valves,certainly the PM3 is.(Equiv NR15)
__________________
G8JET BVWS Archivist and Member V.M.A.R.S |
20th Sep 2020, 5:02 pm | #10 |
Octode
Join Date: Dec 2017
Location: Morden, Surrey, UK.
Posts: 1,559
|
Re: Anyone recognise this naval equipment?
Certainly is from the valves - PM4DX and PM24A.
From my Dad`s handwritten Navy / Army / Air Force / Commercial equivalents book which pre-dates CV types. |