[Milsurplus] SCR 522

[Ray Fantini]

I don’t know, maybe it’s me. I have read the green books years ago along with a bunch of other stuff. But my speculation about the Brits and adaptation of VHF had a lot to do with their early war experience. During the Battel of Britan by monitoring Luftwaffe air to air and air to ground channels during preflight tuning a good estimate can be prepared of what would be upcoming. That would be all HF stuff and although the German aircraft were sitting on the ramp, enough signals could be detected at distance to gather information. All of this being HF AM. Germany did use VHF directional antennas, Knickebein radio navigation for blind bombing and the Brits did a good job of intercepting and redirecting. Search “Head aching and Aspirin” and the Battel of Britan for more information.  Think there was a book that I read years ago called the “Battel of the Beams” or something like that.
To avoid the problem of communications going too far to be of use to the enemy and to accommodate lots of traffic using the limited HF bandwidth VHF for air to ground and air to air was the answer. Nineteen forties technology was barely able to accomplish that so the assumption would be its relatively secure and similar channels assignments can be used in multipole locations without confusion like what would sometimes happen with HF
The answer for the Brits was the TR-5043 or 5-1143 or something like that Bendix copied for US SCR-522, we did have an ARC-5 style Command set, the T-23 and R-28 but they sucked. The channelized auto tune 522 was far superior and quickly adapted for all applications. Or at least until superior designs like the ARC-1 and ARC-3 came out but VHF-AM ruled the day for aircraft opps, VHF-FM developed along a completely different line for ground communications.
Because the ARC-1 and 3 quickly replaced the SCR-522 tons of SCR-522 hit the surplus market after the war,  although it was only maybe five years at the most between design and fielding of  the ARC-1 and 3 they had the benefit of newer tubes and technique that enabled some ARC-3 radios to stay in services as long as the seventies, where the SCR-522 was thru by 1945
The 522 drawbacks were a boom to the Ham community. Maybe it’s not well remembered today but early Ham two meters before the rise of repeaters was all AM, look at all the old Heathkit lunch box radios or “Gooney Box” CD sets,  all that stuff was AM, so the 522 would fit right in at the time until you started looking at some of its limitations like its broad bandwidth and low sensitivity.
The CQ Surplus conversion manuals treated the 522 as being used for AM from what I remember, may have been something regarding FM but I don’t recall it myself. But as my wife will tell you I am often wrong.
I think in your case of dealing with the B-17 and ETO the SCR-522 is the only radio to consider. Although I think a lot of the B-24 liberators were already being equipped with radios like the ARC-1 but anything being operational in the ETO would be using a SCR-522 prior to Overloard, another thing to also consider that by the time of Overloard or just after we had learned a lot about combined ground to air operations and had by that time moved to a model of using forward air controllers and most air support would be thru a FAC and not directly to ground units so cannot Imagin many SCR-522 being used on the ground for that function, espicaley in an armored vehicle.
At least that’s my limited understanding, not trying to be difficult or derogatory but just wanted to have an open discussion.
On a personal level I have to say that the SCR-522 is one radio I have never mastered and, being you have at least two up and running I consider that a huge technical accomplishment and worthy of respect.
Let’s see what others may have to say on the subject.

Ray F/KA3EKH


________________________________
From: milsurplus-bounces at mailman.qth.net <milsurplus-bounces at mailman.qth.net> on behalf of Charlie L. via Milsurplus <milsurplus at mailman.qth.net>
Sent: Monday, April 20, 2026 9:37 PM
To: milsurplus at mailman.qth.net <milsurplus at mailman.qth.net>
Subject: [Milsurplus] SCR 522


I can't find my post about it either, but I have 2 of them, one working on its original dynamotor PS, and intended for the B17 'Lucky Thirteen', the other I will eventually get going on just a DC supply.  I was thinking that the 522 was featured in CQ's surplus conversion manual as a rig folks converted to FM, and maybe confused myself with the AM/FM issue from that,  if I can find my manual I will check that again.  Details of what the capability of the Germans were comm wise, and why the US played catch up can be read in the post WW II book, volume 1, 'The Emergency'.  SCR522's were retrofitted in B17's to allow them to communicate with British aircraft and ground directly.  Tankers conshawed them from depots and put them in Shermans to do the same thing, and eliminate the step of having to request air support and to direct fire without having to relay back wards, then over to the Brits.  US Comm was pretty fouled up prior to and at the start of WW II, but we figured it out.  The Army had to learn how to properly relay a message from station to station with zero defects  by using ARRL information  after seeing  hams doing it every day.

Charlie in NC
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