[ARC5] British WWII Avionics

Sun Jul 8 13:14:02 EDT 2012

After experiencing what a POJ the SCR-522 was at a friends around 1956 I 
picked up/converted the ARC-5 VHF rig and built a tuneable receiving 
converter....much much better. The next progression was a W2AZL clone 
crystal controlled converter and a HB 829B transmitter which was kept 
operational into the late 60's when I went SSB/CW and got into meteor 
scatter and "DX".

----- Original Message ----- 
From: "Sandy" <ebjr37 at charter.net>
To: <jfor at quikus.com>; "Robert Eleazer" <releazer at earthlink.net>
Cc: <arc5 at mailman.qth.net>
Sent: Sunday, July 08, 2012 11:45 AM
Subject: Re: [ARC5] British WWII Avionics

> Amateur conversion of the SCR-522 were popular before the advent of the
> Gonset Communicator.   The BC-624's used the somewhat "dull" 9003 pentodes
> instead of the later 6AK5's.  These could be substituted and it picked the
> sensitivity up quite a bit.  The set had some very good points in spite of
> it's vintage.  What "MADE" the BC-624 and hopped up the BC-639 receiver 
> was
> the advent of the 6BQ7 cascode dual triode preamplifier.  It quickly drive
> the old 6AK5 into oblivion as a decent RF stage capable of a decent noise
> figure.
>
> There was nothing that could be done on improving the transmitter section 
> of
> the '522.  Some of the locals added things like the Millen design 829B
> amplifier for more RF output.  Later the AX9903/5894 dual tetrode became
> very popular on 2 meter AM.
>
> One amateur who owned a construction company (Bill Kelly W5MXJ) converted
> quite a few SCR-522's and used them for communications in his construction
> equipment and trucks instead of spending big bucks on the double bucket
> Motorola FM stuff.  Bill was an inveterate tinkerer with VHF gear in his
> amateur career.
>
> 73
> Sandy W5TVW
>
> -----Original Message----- 
> From: J. Forster
> Sent: Saturday, July 07, 2012 9:28 PM
> To: Robert Eleazer
> Cc: arc5 at mailman.qth.net
> Subject: Re: [ARC5] British WWII Avionics
>
>> I note that all of the SCR-522 sets have both U.S. and British nametags.
>> I wonder if any other equipment had that feature?
>
> Some BC-929's were double badged, and I've seen at least one with an added
> RAF nameplate. I suspect some APN-4 LORAN-A sets were also.
>
>> The 522 must not have been too horrible, because it appears that the
>> receiver formed the basis for the BC-639 ground radio, which of course
>> dispensed with that bizarre crystal tuning scheme.
>>
>> I read that the British invented microwave airborne radar and bought it
>> to the U.S.
>
> I believe it was more the Microwave Magnetron. A sample was brought to the
> US on the Tizzard Mission.
>
>> They thought the Americans were boastful when they described
>> their enthusiasm for the new technology and how they would use it.
>
> The British magnetron was hogged out of a solid copper block. Copper is
> hard to machine, because it is soft and tears badly.
>
> The sample was shown to Percy Spencer of Raytheon and he worked out how to
> mass produce the thing by furnace brazing a stack of punched out plates,
> interspaced with solder preforms. Maggies made this way could be made in
> numbers that staggered the British, and because the cavity strapping was
> better, produced a lot more power.
>
>
>> But a month after the British introduced the U.S. to the radar
>> technology the U.S. knew as much as the British and had designed their
>> own version of the set, with a better receiver.
>
> The MIT Rad Lab was set up to do that kind of thing...  from concept to
> working model very quickly. Companies like Raytheon followed a half step
> behind.
>
>> A month after that the new factory to build
>> the sets was completed.  And a month after that the set was in full
>> production.  The British were astonished.  The Americans were not
>> bragging but simply stating facts.
>
> R&D and the vast US industrial base was capable of very fast quantity
> production. Remember, much of the surplus we are playing with still was
> built in under 4 years.
>
>> The British quit building the sets and just bought them from the U.S..
>> They eventually started building some of their own later, just so they
>> would not forget how.
>
> The US had big advantages, including about ten times the population, vast
> natural resources, and a huge industrial base. It was also not under siege
> and at the end of a long, U Boat threatened, supply chain.
>
>> I think the same thing happened with the SCR-522.
>>
>> As for British bomber radios, I would guess they had no need for a
>> "command set."  The RAF heavy bombers did little daylight formation
>> flying until the latter part of 1944, when the USAAF had pretty well
>> cleaned up the Luftwaffe relative to the shorter range missions, such as
>> to France.
>
> The RAF did a lot of night-time bombing, guided by the Pathfinders.
>
>> I wonder if the B-17's, B-24's and B-25's the British operated used U.S.
>> or British radios?
>
> Almost certainly US radios, I'd think.
>
> -John
>
> ==================
>>
>> Wayne
>
>
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2012.0.2195 / Virus Database: 2437/5118 - Release Date: 07/08/12
>
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1424 / Virus Database: 2437/5118 - Release Date: 07/08/12
> 