[Milsurplus] Chicken or Egg Question

[Jack Antonio]

It is frustrating trying to clean and  organize the shack, I keep 
getting distracted.

Current distraction is that I found a Bendix Aviation Radio Catalog,
copyrighted 1941.

In it is an IF-12 Portable Frequency Indicator, which looks exactly like
a BC-221.

So the question is, which came first? Did the military adopt the civilian
component, or did Bendix market commercially something developed
for the military?

Also found a listing for an RA-12 Instrument Landing Receiver, and
its companion ground transmitter, the TG-12  Looks
like a midway step between the Navy's ZA system, and the Army's later
RC-103 and AN/ARN-5.  Used one 93.3 Mc transmitter for both localizer 
and glide slope.
This is going to take some more research. (Another distraction).

Jack Antonio WA7DIA/4