[Milsurplus] JAN Dual Tetrodes

[Scott Johnson]

My guess is that they were simply used in DOD purchased prog line gear.  I 
have a military PA designed to boost the output of a military UHF airborne 
transceiver, such as an ARC-27/34/51 etc. to 50W carrier for some unknown 
purpose, has one of the "super" 5894 type tubes similar to the ones used in 
hi power Motracs (the number escapes me), but I have never run across a 6907 
in mil gear, airborne or otherwise.

Scott
----- Original Message ----- 
From: <gl4d21a at juno.com>
To: <milsurplus at mailman.qth.net>
Sent: Tuesday, June 28, 2005 8:21 PM
Subject: [Milsurplus] JAN Dual Tetrodes


>
> Hollow state discussion.  Silicon fanatics need not read.
>
> In the beginning there were 829Bs and 832As and some RK somethings or 
> other, then Amperex upped the ante with the 5894 and it's cousins.  And, 
> somewhere in there, Amperex also introduced the 6252, a little bottle 
> which was good to 500 MHZ, but needed cross neutralization.  Badly needed 
> it.  See ARRL handbooks of the '50s.  Around 1955, GE Mobile Radio went to 
> Amperex and said: "If you can get that bottle self neutralized in the 
> 450-470 MHz band, we'll buy a whole bunch.  Oh, and by the way, it also 
> needs to work from 405 to 420, too."  And, so, the 6907 was born.  And GE 
> Progress Line 450 used two 6907's in every transmitter.  The higher power 
> version of the bottle never materialized, even though all transmitter 
> chassis had two sets of holes for the plate circuitry of the final 
> amplifier, one for the 6907, and a second, slightly further away for a 
> taller, more powerful tube.  No, 5894s won't fit, darn it.
>
> What does this have to do with milsurplus?  Well, I think I asked before, 
> with inconclusive results.  What government equipment used 6907s?  In 
> clearing out the estate of an SK MARS member, I found several 6907s in 
> typical military disintegrating cardboard boxes, and with JAN nomenclature 
> stencilled on the glass.  I have never known of any other application for 
> that bottle than GE 2-way, and am real curious about why JAN versions 
> would be produced.  I suppose it would be a natural in 225 - 400 MHz 
> military aircraft comms equipment, but I am not familiar with enough 
> different models to know of an actual use.  What am I missing?
>
> Experts?
>
> 73,
> George
> W5VPQ
>
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