[Milsurplus] Pre-WWII Aircraft Radio Transmitters

[DeWitt Clay]

Ray, 
The Navy had the LJ and LM frequency meters to set up the GO, GP, GF on 
frequency. The specs for the GO (1933) called for the rig to 
maintain a given frequency setting to +- .05% of F. The GO-3, GO-7, GO-8, and 
GO-9 Westinghouse rigs are most likely similar in design and 
appearence. The data for the GO-3 (1933) and GO-9 (1940) shows that quite 
clearly. I have no data on the tube lineup for the GO-1, GO-2, GO-4, GO-5, GO-6 
so I can't comment. I'm making an educated guess that the Westinghouse GO-7, and 
GO-8 closely follow the GO-3 and GO-9 in appearence and design. 

73, DeWitt N4QNX 




----- Original Message ----
From: Ray Fantini <RAFANTINI at salisbury.edu>
To: DeWitt Clay <n4qnx at yahoo.com>; milsurplus <milsurplus at mailman.qth.net>
Sent: Sun, June 12, 2011 1:04:02 PM
Subject: Re: [Milsurplus] Pre-WWII Aircraft Radio Transmitters

More on the GO series, the GO transmitter used two 860 (VT-17) tubes in a MOPA 
circuit and  that tetrode was introduced  in March of 1929, a master oscillator 
PA type transmitter of that era (1930-33) would be inherently unstable and 
produce little power at frequencies above 20 MHz. In a MOPA circuit every tuning 

adjustment can have an effect on stability and frequency. In the early thirties 
it was difficult to determine power or frequency above 20 MHz, no less produce a 

working reliable design that can be bolted into an aircraft. I can see the older 

series GO transmitters working great up to 9 or 12 MHz  but 25 or 26 MHz another 

thing entirely. The GO-3, GO-7, GO-8, GO-9 used three tubes, a oscillator, 
driver to decouple the oscillator from the PA and a 803 PA. 


Way more stable design but still subject to instability from shock and 
vibration. I will still stand by my earlier statement that the PA of the 
primitive GO series was capable of being configured as a doublers or maybe 
Tripler to have the transmitter be able to operate the oscillator at a lower 
frequency with improved stability with the LO set to 5.25 MHz and the output 
tank tuned to 21.0 MHz you’ll get something on 21.0 and a lot of stuff on 10.5 
too, all reasons to support a radical redesign as evidence by the apparent 
difference in GO-7 and above transmitters. Need a schematic to answer that 
question.
Ray F
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