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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 3rd May 2020, 1:15 am   #1
thoyer454
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Default New to me RCA AR80

Had another RCA follow me home today, an AR80. Overall it seems in good shape except for the plastic lens over the dials.

Figured I'd find a bunch of info on the web, but not the case - minimal info out there.

Anyone have info / manuals / schematics on it? Looks like a derivative of an AR-77.

Tom
W3TA
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Old 3rd May 2020, 7:23 am   #2
G3VKM_Roger
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Default Re: New to me RCA AR80

Hi Tom,

There was a mention and some photos of an AR-80 in the collection of a UK amateur in the following thread on this forum:-

https://vintage-radio.net/forum/showthread.php?t=67315

Might be worth contacting him?

73

Roger/G3VKM
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Old 3rd May 2020, 10:26 am   #3
g4aaw pete
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Default Re: New to me RCA AR80

Hello Tom

certainly looks like an AR77

http://www.radiomuseum.co.uk/AR77overhaul.html

Can't help you with a schematic though.
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Old 3rd May 2020, 12:04 pm   #4
Dave757
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Default Re: New to me RCA AR80

Hi Tom,

I'm the chap who took the pictures back in 2008, and I never managed to
find any info on the set, but I can confirm that the set you have is
not that one , so there must be at least 2 around!

I know the set that I photographed was subsequently modified by
someone, and is currently (to the best of my knowledge) being
restored to original by its present owner.

If you wish, I will contact him, and ask him to get in touch with you.

Incidentally there do seem to be detail differences from the AR77
such as the speaker and phones output on the front panel, and the
round multipin connector on the rear panel just above where the
tagstrip is on the AR77.

Kind regards
Dave G0ELJ
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Old 3rd May 2020, 7:52 pm   #5
thoyer454
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Default Re: New to me RCA AR80

Hi Dave,

That would be great! Any info on the radio at this point is helpful.

My direct email : Deleted, click on Tom's username.

Thanks,
Tom
W3TA

Last edited by AC/HL; 3rd May 2020 at 8:52 pm.
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Old 3rd May 2020, 8:34 pm   #6
turretslug
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Default Re: New to me RCA AR80

It does seem generally similar to the AR77- I wonder if it's essentially a development of it for the professional market with rack-mounting front panel as opposed to "table" metalwork? It's a bit reminiscent of the SP200 series in presentation, though these are more sophisticated circuit-wise. Are the bandspread scales still marked for the amateur bands, or for something like the marine or aviation allocations? Coverage stopping at 27MHz suggests that maybe the amateur wasn't the prime market for it. There seemed to be quite a few 1x RF, 2x IF general coverage sets in the pre-war US professional category, presumably not everyone needed or could afford the no-messing approach of the AR88 and similar sets.

In the UK, we were probably spoilt post-war in that so many AR88s (and similar-category ex-military receivers) were available, a set like the AR77/AR80 would otherwise have been regarded as pretty mouth-watering by the pre-SSB amateur/keen SWL. Overhauled and aligned to spec., I bet it still makes a very good broadcast receiver.

Colin
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Old 3rd May 2020, 9:13 pm   #7
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Default Re: New to me RCA AR80

Those external illuminator hoods are rather odd- as both the sets mentioned so far have them, it was presumably a standard feature or at least option, yet they're markedly out of keeping with the rest of the front panel. From a stylist's point of view, a considerable detraction from that crisp '30s frontage and from the production engineer's standpoint, rather more metalwork and fasteners than illumination from behind- vis. the AR88's cheapie clip-on bulb-holders. Unless of course, the tuning scales are an opaque material like metal.
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Old 4th May 2020, 1:25 am   #8
thoyer454
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Default Re: New to me RCA AR80

The dial scales seem to be solid metal like an SP-600. No backlighting them.... Although you have to wonder why they didn't down light or side light the dials like the SP-600.

When I get some free bench space (or until my curiosity gets the best of me, whichever comes first), I'll remove the front panel and the crazed plastic lens. Hopefully the dial scales are still in good shape.

The front panel is not your standard rack width (19"). It is smaller. A BIG PLUS is that this radio doesn't weight nearly as much as the AR88's. I can easily move this one around.

Tom
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Old 4th May 2020, 1:27 am   #9
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Default Re: New to me RCA AR80

Couple more pics. Looks very similar in layout to the AR77
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Old 4th May 2020, 4:47 pm   #10
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Default Re: New to me RCA AR80

Quote:
Originally Posted by thoyer454 View Post
The front panel is not your standard rack width (19"). It is smaller. A BIG PLUS is that this radio doesn't weight nearly as much as the AR88's. I can easily move this one around.
Lol, I'm sure many who used to have or would like to own an AR88 are put off by the sheer size and weight of the thing, not just a 6U high front panel but very deep chassis as well, and a serious threat to flimsy furniture. I think that the Eddystone 750 here beats it for mass/unit volume but it is at least notably compact for a half-decent valve radio, 5U and just 24cm deep making it about half the volume.

Reading further into the AR77 literature, it seems that rack-mounting options were available, so that makes my previous supposition about the AR80 less tenable. The coverage of the AR80 being 500kHz to 27MHz as opposed to 540kHz to 31MHz for the AR77 sounds as if it could be done with much the same coilset but a bit of tweaking to trimmers and maybe padders. Maybe RCA felt that a receiver initially aimed at the well-heeled amateur also had potential professional application, able to tune 500kHz for marine applications but not needing 10m coverage and the "AR80" designation served to distinguish it from its otherwise very similar progenitor. Could calibrated metal tuning scales be cheaper to produce in small numbers than setting up to print translucent plastic scales as used on AR77 and AR88?
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Old 4th May 2020, 5:36 pm   #11
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Default Re: New to me RCA AR80

Tom does well in unearthing these interesting mystery sets. First he was accosted by an unusual AR88 variation. Now he has an AR80 which [a bit confusingly] is probably a variation of the AR77. It's definitely not the same as an AR88 on size and shape alone [never mind weight]. The AR77 may well have been more friendly in a smaller or domestic environment as suggested.
At one point I was very keen to actually view an AR77 but a little disappointed to see how different it was to the 88 [despite the 77 being described as a good set in it's own right. Looking at things from the other end of the telescope, I wonder how the research and design carried out with the onset of war resulted in such a massive [in every sense] jump to the bigger Rx from an AR77. Was it primarily the required operational spec for example or did the no expense spared military operational attitude dictate a more high quality and solid item? They seem very heavy now of course and they are but the 88's were used in large Diversity Racks. Mine is labelled "Slave 31" for example, out of how many There would be enough [young] personnel to lift them about back then. Does the large build mean that a greater performance could be achieved than would be difficult in a relatively confined space [it's still well packed as it is]. We've all seen breadboard devices that worked brilliantly but not so when built into a smaller cabinet.

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Old 4th May 2020, 8:50 pm   #12
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Default Re: New to me RCA AR80

I'm thinking that the more exacting governmental-organisation types who would have set the specs for the likes of the AR88 would have been looking for improved image rejection as a priority, hence 2 tuned RF stages, and a need for good selectivity shape factor and AGC capability meant that 3 IF stages seemed wise. Tight screening to assure that good image rejection and low spurios adds metalwork, size and weight. Separate LO valve and voltage stabiliser meant that a frequency could be sat on for hours without the irritation of too much operator twiddling but shunt stabilisers need a good dollop of HT current to keep them favourably centred in their optimum window despite mains fluctuations and AGC-induced HT current changes- say 15-20mA. That 2nd RF stage and 3rd IF stage add maybe as much again. HT current's gone up by 40mA, so mains transformer and chokes need to be 50% bigger.... Those extra valve sockets, IFTs and another switched coilbank with its additional tuning gang section mean that the chassis has got a good deal deeper, and hardware and bracketry need beefing up. Diminishing returns bites with a vengeance!
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Old 4th May 2020, 9:09 pm   #13
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Default Re: New to me RCA AR80

Yes I think that's it TS. Extra stages and parameters well above the 77 standard but also a Rolls Royce build to accompany it all.The unfortunately vulnerable Mains Trans slip might have been a rush to production but they were clearly concentrating on the other end. Imagine it with 2 IF frequencies and a bigger dial.

Dave
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Old 5th May 2020, 1:09 am   #14
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Default Re: New to me RCA AR80

The timing is interesting. As I understand it both the Hallicrafters SX28 and the AR88 were introduced about the same time- 1941, but before Pearl Harbour. Both were aimed initially at the amateur market. The SX28 was widely used by the US military despite being somewhat inferior to the AR88, most of which found their way to the UK.
I wonder if the AR88 being produced in Canada had anything to do wiih it?
BTW I don't recall ever seeing the AR88 advertised in QSTs of the prewar period, whereas the SX28 frequently was.
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Old 5th May 2020, 7:41 am   #15
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Default Re: New to me RCA AR80

AR88s seem almost rare in the US, and very common over here. I think distribution of them was dramatically swung towards export/lend-lease. The UK and Russia being recipients. Are there many in Australia?

The AR77, CR88 etc are unusual sets in the UK. I've heard of people with them, but never seen one in the flesh

The AR8516L was made by RCA in the UK. Interestingly, it has the AR prefix. It sold into the civil maritime market in the sixties, where it was considered to be not quite wonderful and there was some sort of partially covered-up monkey business which saw many of them taken out of ships and dumped onto the amateur radio market. It's got a lot in common with the CRM-R6A which is rare here, but common in the US, now this one has the CR prefix! I knew someone who bought an AR8516L, a very impressive bit of kit for an amateur in the late sixties, and rather expensive for the amateur market even second-hand. AR8516L being AC/DC for ships and had a cheapened-off IF system.

Oh, I once saw a Japanese copy of an HRO.

David
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Old 5th May 2020, 5:16 pm   #16
John KC0G
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Default Re: New to me RCA AR80

I vaguely recall Pat Hawker, G3VA, writing in one of his Technical Topics columns that the AR88 was designed to meet a British joint military services specification. It would a lot of hunting to find it.

73 John
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Old 5th May 2020, 5:38 pm   #17
thoyer454
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Default Re: New to me RCA AR80

Quote:
Originally Posted by Radio Wrangler View Post
The AR8516L was made by RCA in the UK. Interestingly, it has the AR prefix. It sold into the civil maritime market in the sixties, where it was considered to be not quite wonderful and there was some sort of partially covered-up monkey business which saw many of them taken out of ships and dumped onto the amateur radio market. It's got a lot in common with the CRM-R6A which is rare here, but common in the US, now this one has the CR prefix! I knew someone who bought an AR8516L, a very impressive bit of kit for an amateur in the late sixties, and rather expensive for the amateur market even second-hand. AR8516L being AC/DC for ships and had a cheapened-off IF system.
I have an AR-8516 non L. Nice radio but mostly 3 volt tubes with filaments wired in series.

Tom
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PS: Radio came from the same source as the AR80 in this thread.


More pics on my web site www.thdesignsinc.com scroll down to radio projects
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Old 6th May 2020, 5:28 am   #18
John KC0G
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Quote:
Originally Posted by John KC0G View Post
I vaguely recall Pat Hawker, G3VA, writing in one of his Technical Topics columns that the AR88 was designed to meet a British joint military services specification. It would a lot of hunting to find it.
Found it. On page 52 of the May 1994 issue of the RSGB's Radio Communication, Pat commented that some years before he had been told this information by Ron Glaisher, G6LX. He used the term inter-service specification. Apparently the resources were not available in the UK and a delegation was sent to the USA and persuaded RCA to develop the receiver.

73 John
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Old 6th May 2020, 10:08 am   #19
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Default Re: New to me RCA AR80

It seems an odd oversight that the AR88 didn't (at least in initial bulk wartime production) feature a front-panel crystal phasing control whilst the earlier and less comprehensive AR77/80 did. Surely for a top-flight comms receiver, a minimal-expense option for nulling adjacent QRM when reading code signals would feature on the "wanted" list. As discussed recently on the forum, adding front-panel crystal phasing to later sets was a very simple production alteration, just a trivial re-arrangement of controls, a short flexi-shaft and an extra knob. Like the AR88, the British CR100 featured a single crystal for tight selectivity with internal pre-set phasing- perhaps they were specified from a similar background in the UK.
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Old 6th May 2020, 12:26 pm   #20
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Default Re: New to me RCA AR80

The phasing variable capacitor is there, halfway back inside. It was just an extension shaft and a knob missing. Not so much saving, maybe more a wish to keep the panel layout symmetrical?

David
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