[Milsurplus] Navy Nomenclature "a" Usage Variations

[Mike Morrow]

Robert wrote:

> The GF transmitter was used with RU-2 receiver.  RU-2a was supplied with
> a beacon band coil set and operated stand alone.

I posted a couple of days ago on the ARC5 list a discussion of the early RU/GF
components, which seem to illustrate further unpredictability on the way the USN
applied such things as the "a" modification designation.

For example:

The GF transmitter CBY-52004 was initially used with the GF receiver CBY-46006
(1932).  This receiver looked like a RU-type, and had no AGC or CW oscillator.

At some point, the system was modified to use the RU-2 receiver CBY-46012 (1932),
with a reduced coil set, and likely a different junction and control box.  (I
don't have a GF/RU-2 system component listing to compare to the GF/GF listing.)
The RU-2 was also used with a full coil set for some liaison transmitters.  The 
RU-2 had a CW oscillator, but no AGC.

The RU-2a (1937) also used the CBY-46012 receiver for the beacon band only.

The GF-1 transmitter CBY-52027 was used with the RU-3 receiver CBY-46036 (1934),
with reduced coil set.  The RU-3 could also be used as a liaison receiver,
with full coil set.  The RU-3 had a CW oscillator and AGC.

The GF-2 transmitter CBY-52028 was used with the RU-3a receiver CBY-46041 (1934).
The RU-3a used a reduced coil set, and a receiver different from that used for
the RU-3 (46041 vs. 46036). 

I don't know what the differences between the 46036 and the 46041 are, but they
are likely small.  All RU receivers (and the oddball RAJ receiver CBY-46046) had
CW oscillators and AGC beginning with the RU-3.

So in this short history, we see the "a" used in RU-2a for an RU-2 with beacon
band only coil set, and the "a" used in the RU-3a, which uses a different receiver
than that used in the RU-3.

I hate the pre-war USN nomenclature system.  One can't tell by the Txx designation
if the item is just a transmitter, or a transmitter-receiver.  I guess the Army system
is much worse.  One can't tell anything about function from SCR or BC designations.

Mike / KK5F