[Milsurplus] was: Pre-WW2 USAAF nomenclature

[Hue Miller]

So-

the "middle codes" were not exclusive to the USAAF, but were 
used for the USA ground Army also?

Again, what did the first letter of the two letter middlecode 
represent?
Examples, BC-RC-183, BC-SA-167

Isn't it surprising, for apparently how few prewar SCR-183's
survived, how many actual production runs there were?
( AA thru AS at least )

I wonder if in the US Army there tended to be less of a need for
long-distance type aircraft radio than in the US Navy and USCG.
Witness the ultra-rare CW add-on for the SCR-183 series.
William, do you know which  SCR -A*-183 set used the CW 
oscillator.
I note that the Navy's similar RU receivers all - apparently -
were CW capable from the start.
-Hue Miller