[ARC5] WWII Aircraft Set- Primer?

[Mike Morrow]

> ...the aircraft version on the TBW was the GO-9...

And the principal electrical distinction was the TBW's 843 PA grid modulator stage. which allowed A3 emission.  The GO-9 is A1 and A2 only...with A2 generated from the 800 Hz primary AC power.

> Question, somehow I have only ever seen GO-9, was there a GO-8 or 7?

There were 11 different GO-series liaison transmitter systems between 1933 and 1944. All were A1 and A2 emission.  The intermediate frequency transmitter for all covered 300 to 600 kHz MF.  The HF transmitter frequency coverage in kHz varied:

GO      1933     Hygrade-Sylvania     4000-13575 
GO-1    1934     Western Electric     3000-13575
GO-2    1935     Western Electric     3000-13575
GO-3    1937     Westinghouse         3000-13575
GO-4    1938     General Electric     3000-26500
GO-5    1939     General Electric     No HF unit
GO-6    1939     General Electric     3000-26500 (No IF unit)
GO-7    1940     Westinghouse         3000-13575
GO-8    1940     Westinghouse         3000-13575
GO-9    1940     Westinghouse         3000-18100
GO-9a   1944     Westinghouse         2200-18100

The scant surviving technical information indicate that there were major design differences from one manufacturer to another.  Most except the GO-9 were likely made in quantities well under 100, so very little equipment or tech info has survived for most GO sets..

List member George has what is probably the only surviving 1939 GO-6 HF transmitter, and the Pensacola Naval Aviation Museum has a cutaway PBY on display that appears to have a 1935 GO-2.  Everything else that has survived seems to be a GO-9 unit.

> Also the TBW and the GO-9 were so close but yet not the same, 
> how did that happen?

Patrol plane communication service requirements differ greatly from those of "portable" ground communications service.  What is remarkable is that the GO-9 and TBW transmitter units are so similar, not that they differ in small details.

> What came first?

The first GO was made in 1933, and the first Westinghouse GO-3 in 1937...years before the Westinhouse TBW.

Some other GO-related notes:  I believe the amazing upper limit of 26500 kHz for the 1938 GE GO-4 is what motivated A.R.C. to develop the RAT and RAT-1 (13500 to 27000 kHz) sets to extend liaison receiver coverage beyond the 13575 kHz limit of the RU-11 and RU-12 liaison receivers.  Further, it seems that A.R.C. designed the eight-receiver RAV 190 to 27000 kHz set to replace the RU-12/RAT-1 with modern superheterodyne receivers.  However, the A.R.C. RAV was definitely the inferior set in most qualities to GE's RAX-1 three-receiver liaison system.  The RAX-1 had much better staging in its two receivers that provided most of its 200 to 27000 kHz coverage.  Only 46 RAV liaison receiver sets were made, while the RAX-1 was made in the thousands.

A.R.C. made up for it with five receivers identical to or very slightly simplified from the RAV system becoming standard "command" set radios purchased by the tens of thousands.

Mike / KK5F