[ARC5] [Milsurplus] Airship radio equipment? (1933 RU/GM??)

[Mike Morrow]

Nick wrote:

> See photo of the airship USS Macon radio room at
> http://www.moffettfieldmuseum.org/photos/showimg.php?file=/Macon/Interior/macon_inside13.jpg

Robert wrote:

> My guess, based on one inconclusive data point and the rather large size, 
> is that it is either a GK or a GK-1.  I don't know of any photograph 
> available that is identified as such.  But SHIPS 242A lists only one transmitter
> as being for Rigid Airship, the GK-(*).  500 W output.  Covers 5 narrow bands 
> (about 2 MC wide on the higher ones) between 300 KC and 18.1 MC.  Made by 
> Westinghouse 1930 and 1932.  Emission A1 & A2.  Paired with the RU.

The transmitter pictured in Nick's link seems very *small* for a 500 watt
transmitter, one which likely had separate IF and HF sections like the
earlier GH and GI units.  The pictured transmitter would have been of 1933
technology, and it is only slightly larger than the RU-* next to it.  The
RU-* and G? control boxes pictured in the top left are fascinating.  They
lead me to think that this installation is a command set with typical remote
control capability.

My guess is that it might be a GM, which is discussed briefly at the top of
page 68 in this interesting 1935 document found on Mike Hanz's site:

    http://aafradio.org/docs/1935-Navy-Radio-Gear.pdf

That page states that the GM was used with the RU-2 for VF (fighter) and
VB (bomber) squadrons, so an installation on an airship wouldn't be too
unexpected.  SHIPS 242A says that the GM covered 3000 to 4525 and 6000 to
9050 kHz (A1, A2, A3) and was made by National in 1933.  The USS Macon ZRS-5
( http://en.wikipedia.org/wiki/USS_Macon_(ZRS-5) ) was commissioned in 1933
and was lost in a crash in California in 1935.  The 15-watt GM would serve
well as a command set, given the Macon's role as an aircraft carrier for 
F9C-3 Sparrowhawks ( http://en.wikipedia.org/wiki/Curtiss_F9C_Sparrowhawk ).

Anyway, it's all just a semi-educated guess on my part.

73,
Mike / KK5F