[Milsurplus] Pre-WWII Aircraft Radio Transmitters

[DeWitt Clay]

I had to rush this off due before due to an approaching thunderstorm, hihi! So 
here are a few more comments from the 1936 Radio Materiel pamphlet (1 inch 
thick, hihi). 

Hygrade Sylvania GO Aircraft Transmitter:


The Navy had the LJ and LM frequency meters availible to set up the GO, GP, GF 
on 

frequency in the 1930s. The specs for the GO (1933) calls for the rig to 
maintain a given frequency setting to +- .05% of F. The oscillator design calls 
for plate circuit doubling of the grid circuit frequency as is the practice to 
improve stability. The discussion of the PA circuit makes no mention of doubling 
taking place there. So the oscillator grid circuit runs from about 1500 KC to 
6800 KC with the oscillator plate circuit doubling from 3000 KC to 13600 KC. The 
860 PA then runs staight thru.
Appearence wise, the GO has the same 3 bay setup we are all familiar with in the 
GO-9. The controls layout are somewhat different but I think most of would 
recognize it as being a GO transmitter.  

I have a couple of other manuals that show Sylvania made a communications type 
receiver about the same time as the GO came out. This plus the GO indicates that 
Sylvania had entered the communications equipment field at that time. Sylvania 
also brought out a line of carbon plate transmitting tubes about 1934.  

I can tell you that the Westinghouse GO-3 and GO-9 are similar rigs in 
appearence and design. The drawings and data for the GO-3 (1933) and GO-9 (1940) 
shows that quite 

clearly. The 1942 Radio Materiel pamphlet listed them as representive of the GO 
line that the aircraft radio man would likely encounter. 

Sorry, I have no info on the tube lineup for the GO-1, GO-2, GO-4, GO-5, and the 
GO-6. 

More fun facts on the GO-3 and GO-9  next time, hi!

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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