[ARC5] Basic Question on Use of Command Sets

[David Stinson]

----- Original Message ----- 
From: "Robert Eleazer" <releazer at earthlink.net>
To: <arc5 at mailman.qth.net>
Sent: Friday, January 07, 2011 7:41 PM
Subject: [ARC5] Basic Question on Use of Command Sets


> Relative to the ongoing discussion of audio output capabilities of ARC-5 
> sets,
>prior to WWII was there any need for such sets to be used in anything
> but fighters and perhaps 2 seat trainers?

Large aircraft with multi-person crews have been in service
since the beginning.  The idea of splitting the radio systems to
accommodate the differing communications missions evolved
slowly through the 1920s SCR-132/-134 era.
It became firmly established in 1932-34 with the introduction
of the SCR-183 (Army) and GF* (Navy) "Command Sets,"
which gave the pilot his own channels to talk to ground
controllers and other aircraft, and SCR-187 (Army) and
"G"-series (GO, GP) "Liaison Sets," which were the
territory of the Radio Operator with his long-range
and frequency-guarding missions.  While the first SCR-274Ns
were produced on 1941 orders, the first Acceptance Tests
dates on ATA/ARA (from which SCR-274N was derived)
were from Feb. 1942.  274N would therefore have come
into Army inventory sometime in the second half of 1942.

Large Army aircraft in service before that date
would have been equipped with SCR-183 / -283
for the "Command" mission.  General Doolittle's "thanks"
letter to Western Electric radio workers in the Kearny, NJ
plant is conclusive evidence that the raid aircraft were
outfitted with SCR-283 (the raid was in April of 1942).
If they had been using SCR-287, he'd have written
General Electric's workers and W.E. didn't start building
SCR-274N until after this date.

There would certainly have been exceptions to
the "two system" standard,
such as a transport aircraft that repeatedly flew
a fixed overland route and had no need for more than
a single set.  But be it 1933 or 1943,
attempting to do the pilot's comm and radio op's comm
on a large ship with a single set would have been a big mess.

73 DE Dave AB5S

*  In the early Navy "Command Set" deployment,
   "GF" designated the full receiver/transmitter set.
    "RU" was the designation for a receive-only set.
   "GF/RU" came into use as a designation later when the Navy
   settled (for a short while) on using "Gx" to designate
   aircraft transmitters like GO, GP etc.