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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 Jan 2021, 4:25 pm | #1 |
Dekatron
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Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
A recent thread on the date of service of a ADF module has piqued my curiosity about one in my possession.
It has 4 tuned stages and embodies transistors, a Nuvistor (as far as I can see) and a valve. It has a physically massive ground plane which is so thick in comparison to its power that seems to also serve as a method for ruggedisation/ blast proofing ad well as EMP-resilience. In the MOD record integers 1-10 are stamped: are these 2001-10? I haven’t disassembled it so can’t give active component deets. 70’s? Early 80’s? (These a my best-guesses, not based on any insight) I did note the comments on the length of service of modules that are doing a perfectly good job so don’t get replaced just because of tech advances that don’t do anything to improve on outstanding existing quality. Shame some of the leads were hacked; it’s in otherwise perfect nick.
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Al Last edited by Al (astral highway); 5th Jan 2021 at 4:43 pm. Reason: Clarification. |
5th Jan 2021, 4:35 pm | #2 |
Nonode
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Re: Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
The Mod Record tells you nothing regarding dates. As each successive modification is embodied the numbers are struck through sequentially to record its incorporation.
Andy |
5th Jan 2021, 4:41 pm | #3 |
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Re: Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
Part of PTR 175 comms radio, Plessey I think:
https://www.blunham.com/Radar/Signal...oInstnList.pdf http://members.home.nl/a.k.bouwknegt...en/PTR175_.htm https://scottbouch.com/ptr175.html Lawrence. Last edited by ms660; 5th Jan 2021 at 4:48 pm. Reason: links added |
5th Jan 2021, 4:56 pm | #4 |
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Re: Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
It's built into a casting. Don't deduce anything from the wall thickness other than it had to be so to leave some material when the screw holes were drilled and tapped.
Basic sand-castings are normally rough-surfaced, so where you need a lid to fo on, a valve holder to seat or a PCB to seat, you have to get a milling cutter in to prepare a smooth, level face. Ditto for outside faces that fit onto other things, where screw heads seat, connectors fit etc. Better grade castings can be a bit more detailed, so you can have thinner walls and put bosses where you need a drilled and tapped hole. This saves weight. Not too important in ground avionics, but very valuable in flying avionics. In the military and aviation circles, they don't want to keep re-inventing the wheel because of the costs of certification/proof as well as the logistics of spares holding, test procedures etc. So things stay in use a lot longer than is normal for consumer stuff - a cellphone design has the life expectancy of a mayfly! So, it's hard to say when something was made or used, but looking at the design, the technologies used and the parts used can set an era for when the thing was designed. Miniature B9A B7G valves say early 50's onwards. What looks like a TO-5 transistor can on a plastic seat on a piece of board says mid sixties onwards. Those look like ptfe insulated turret tags in some places. I'd say it was designed arounf mid sixties parts and techniques. David
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5th Jan 2021, 5:08 pm | #5 |
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Re: Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
Thanks, Lawrence. Brilliant work!
So based on a unit designed in the early seventies fits well. It's an aircraft comms radio covering the 118MHz civilian frequency range as well as the military UHF channels. 48 toobs and a few transistors in the mixer/IF areas. Fits nicely. David
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5th Jan 2021, 5:17 pm | #6 |
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Re: Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
In the first photo, is that what looks like a Nuvistor in the middle compartment next to the B7G valve?
Nuvistors were invented by RCA and the first ones were released-to-market in 1959. http://www.r-type.org/articles/art-150.htm |
5th Jan 2021, 5:56 pm | #7 | |
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Re: Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
Quote:
Lawrence - thanks ! Great sleuthing! And David - interesting , I’ve learned something completely new there.
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Al Last edited by Al (astral highway); 5th Jan 2021 at 6:04 pm. |
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5th Jan 2021, 6:07 pm | #8 |
Heptode
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Re: Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
That looks vaguely familiar. Were versions fitted to EE Lightnings, and early-ish Harriers? If the latter, then their performance left a lot to be desired, and pilots were always grumbling about them. During the Falklands conflict, they regularly went unserviceable, leading to a fully armed aircraft returning to the carrier. If they had a heavy bomb load, the weapons were jettisoned before attempting a landing.
Colin |
5th Jan 2021, 7:37 pm | #9 | |
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Re: Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
Quote:
Thanks, Colin, that does sound like a woeful performance. How on earth could that be allowed to be put into service? G6 Tanuki: here's the link to the Nuvistor-based converter I built in 2009, in case you're interested. This set does intrigue me with its concurrent use of silicon, Nuvistor and conventional valve - David, when you say '48' tubes, what's the full designation so I can look it up? Thanks
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5th Jan 2021, 8:32 pm | #10 |
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Re: Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
In the documents Lawrence has.. it's listed as having 48 tubes in the full radio.
David
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6th Jan 2021, 12:17 pm | #11 |
Nonode
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Re: Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
Right enough, PTR175 came into RAF use in late 60's/early 70's. It was a modified version of ARC52. ARC52's original 220MHz - 399MHz range was extended lower to encompass the VHF frequencies formally handled by the old 10channel 1985 series.
Silly me actually had one, so should've remembered. However, I donated it to the Shackleton Restoration project at Coventry Airport, along with its 3" thick 800 page AP, several years ago. Both ARC52 & PTR75 were in totally pressurised rugged enclosures which were cooled by a fan attachment on the front mounted rotary PSU. Both were also used with the "Violet Picture" SARBE S&R homing equipment. Seemingly, Birketts in Lincoln, years ago, had a storeroom full of all this equipment, when it became redundant(replaced by PTR370). 30MU at RAF Sealand had hundreds of sq. yards of workbench space & dozens of J/T's & Cpl's working constantly for years, I remember from by visits there. And to a lesser degree 103MU out in Cyprus, where I worked in the late 60's. Regards, David |
7th Jan 2021, 11:36 am | #12 |
Heptode
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Re: Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
There was one advertised for sale on an auction site recently, and the seller identified it as fitted to the Harrier GR3, which was the Mark that the RAF sent down to the Falklands. Hence my earlier comment about servicability and reliability. We never really got on top of the problems, and why an update and/or new design was urgently sought.
Colin |
7th Jan 2021, 5:07 pm | #13 |
Nonode
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Re: Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
Am I correct in guessing, Colin, that you too are ex RAF ? Talking of "North Yorkshire" - my first posting after leaving B/E training at Cosford was on 202(formerly 228) S&R Helicopter Squadron at Leconfield. During my time there the Whirlwinds underwent a major up-grade to MK10's which included changing from 1985 series VHF/SARAH to ARC52/VP. From what I recall from 58 years ago, there weren't any reliability issues. Some years later I did a couple of short stints on 56 & 111 Lightning Squadrons, and also seem to remember that their ARC52's were reliable. However, I remember very little about PTR175, & SFA about PTR370.
Regards, David |
7th Jan 2021, 9:07 pm | #14 |
Heptode
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Re: Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
Not RAF, but supplier research and development plus 'brewing' mods to improve or circumvent bugs/inadequacies. I now live 2 miles straight line distance from Teesside International Airport, formerly RAF Middleton St George. 226 (OCU) Squadron Lightnings were based here and I sometimes went spotting as a teenager. I spent a lot of time on sets for Harriers, particularly the GR3 variant at Wittering and Gutersloh. After the Falklands conflict, we had a huge list of grumbles to clear. Not only the radio was subsequently modded, but also the antenna and its placing.
Now, 72-year old, with failing memory, much of my career is hazy. Hence not being sure if the mentioned set had been used on Harriers. Colin |
8th Jan 2021, 5:22 pm | #15 |
Nonode
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Re: Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
Hey Colin,
Middleton St George was one of our 202 Sqdn's Helicopter bases. HQ being at Leconfield. Right enough, being over 3 score years & ten certainly taxes one's memory. I can remember several highlights from the 60's, but trying to pinpoint a particular month in a particular year is difficult. Mind you, threads like this one are certainly enjoyable, and do bring back memories. Like being sent to RAF Feltwell on a three week in-depth course on ARC52. Plop one on my workshop bench now - I wouldn't have a clue ! Regards, David |
13th Jan 2021, 11:40 pm | #16 |
Triode
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Re: Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
i should think it must have been it was produced after 1974,this is due to the fact that the nato stock number includes a "country code" which is 99. 99 is for u.k. up until '74 the nato stock number didnt have the origin country code as it followed the old f.s.n (federal stock number) system of the us govt. 00,01 are u.s. designators. as its quite likely it originally was an older design that remained in service over a period of years.later productions and replacement modules would reflect the stock numbering system of the era in which they were produced
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25th Jan 2021, 5:48 pm | #17 |
Heptode
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Re: Date of mfr. and service of this (avionics?) VHF/ UHF amplifier module?
It's all coming back to me now. The radio fit in the Falklands-era GR3s was comprised of 5 units connected by bundles of wires (without any notations on each wire). Many problems came about from poor connections and a dodgy relay box. The 'toobs' didn't behave too well in a 6g manoeuvre as they weren't properly restrained in some cases.
Hope that helps. Colin Last edited by camallison; 25th Jan 2021 at 5:49 pm. Reason: Spollong! |