[ARC5] British WWII Avionics

[D C *Mac* Macdonald]

The transmitter I built up on a 19" rack panel 
so my novice-licensed bride (WN6DFR) could 
get on phone back in 1962 still resides in my
garage. If there were any AM operation going 
on, I'd try to get a power supply for it. I had 
two original RA-62(?) for it, but they went to 
a landfill when tornado took house in 1999. 
I used it in Ft Worth, TX for several years 
along with a BC-639 (sold a few years ago), 
an Ameco Pre-amp and Cushcraft 16 element 
collinear array. Lots of fun back then. 
 
BTW, same bride is now KA5BJS. 
  
* * * * * * * * * * * 
* 73 - Mac, K2GKK/5 * 
* (Since 30 Nov 53) * 
* k2gkk at hotmail.com *  
* Oklahoma City, OK * 
* USAF, Ret (61-81) * 
* * * * * * * * * * * 
 
 
 


 

> From: ebjr37 at charter.net
> To: jfor at quikus.com; releazer at earthlink.net
> Date: Sun, 8 Jul 2012 10:45:26 -0500
> CC: arc5 at mailman.qth.net
> 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