[ARC5] [Milsurplus] Pre-WWII Aircraft Radio Transmitters
jcoward5452 at aol.com
jcoward5452 at aol.com
Sun Jun 12 18:31:55 EDT 2011
Hello All,
DeWitt mentions LJ frequency meter. I have not heard of this one, Can anyone elaborate on this? Do any exist today and in what time frame was it developed ( I presume WWI to between the Wars like 1935)?
Thanks,
Jay KE6PPF
-----Original Message-----
From: DeWitt Clay <n4qnx at yahoo.com>
To: milsurplus <milsurplus at mailman.qth.net>
Sent: Sun, Jun 12, 2011 2:54 pm
Subject: [Milsurplus] Pre-WWII Aircraft Radio Transmitters
I had to rush this off due before due to an approaching thunderstorm, hihi! So
ere are a few more comments from the 1936 Radio Materiel pamphlet (1 inch
hick, hihi).
Hygrade Sylvania GO Aircraft Transmitter:
he Navy had the LJ and LM frequency meters availible to set up the GO, GP, GF
n
frequency in the 1930s. The specs for the GO (1933) calls for the rig to
aintain a given frequency setting to +- .05% of F. The oscillator design calls
or plate circuit doubling of the grid circuit frequency as is the practice to
mprove 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
800 KC with the oscillator plate circuit doubling from 3000 KC to 13600 KC. The
860 PA then runs staight thru.
ppearence 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
ecognize it as being a GO transmitter.
I have a couple of other manuals that show Sylvania made a communications type
eceiver 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
lso 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
ppearence 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
ine 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 ----
rom: Ray Fantini <RAFANTINI at salisbury.edu>
o: DeWitt Clay <n4qnx at yahoo.com>; milsurplus <milsurplus at mailman.qth.net>
ent: Sun, June 12, 2011 1:04:02 PM
ubject: Re: [Milsurplus] Pre-WWII Aircraft Radio Transmitters
More on the GO series, the GO transmitter used two 860 (VT-17) tubes in a MOPA
ircuit and that tetrode was introduced in March of 1929, a master oscillator
A type transmitter of that era (1930-33) would be inherently unstable and
roduce 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
t 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,
river to decouple the oscillator from the PA and a 803 PA.
ay more stable design but still subject to instability from shock and
ibration. I will still stand by my earlier statement that the PA of the
rimitive GO series was capable of being configured as a doublers or maybe
ripler to have the transmitter be able to operate the oscillator at a lower
requency with improved stability with the LO set to 5.25 MHz and the output
ank tuned to 21.0 MHz you’ll get something on 21.0 and a lot of stuff on 10.5
oo, all reasons to support a radical redesign as evidence by the apparent
ifference in GO-7 and above transmitters. Need a schematic to answer that
uestion.
ay F
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