[Milsurplus] GP 7 Transmitter Question

[WA5CAB at cs.com]

First, don't butcher the TU.  It is highly unlikely you will get anything out 
of it that you will ever do anything useful with.  Many years ago, I nailed 
the front panel from one of the TU's to a bulkhead in my shack to remind me of 
that fact.

If you keep it intact long enough, sooner or later, someone will need it, if 
only to repair one that someone else butchered.

The GP-7 was the 8th and final model of the Navy GP series of aircraft 
transmitters.  For some reason, as with the GO-9, it is almost the only model that 
ever seems to turn up.  All I can figure is that the Navy deliberately 
destroyed all of the earlier models rather than let them go to surplus sales.  I've 
heard from a couple of people who have a GP-6 and one who had a GP-3 but never 
heard of anyone with any other models.  The GP-7, like the TBX-8 and TBY-8, 
seems to have survived in some quantity because it was produced right at the end 
of the War and many were never issued.  It's intended function was the same as 
that of the competing GO, TCX, ATC and ATD, a medium power aircraft 
transmitter.

The GP covers 350-9050 KC AM/MCW/CW.  Like several other late Prewar designs, 
it uses plug-in single band tuning units instead of bandswitching.  Slightly 
smaller than the ATC and ATD, it's input power was 115 VAC/800 CPS.  Final 
amplifier tube was an 803 and it used low level grid rather than high level plate 
modulation for voice.  Rated output power was 80-125 watts CW and MCW over 
the operating range and 30-40 watts AM voice.  Physically, its proportions 
(width, height and depth dimensions) are similar to the TCX, ATC, ATD and BC-653 
(and several Postwar Johnson and Heath transmitters), fairly wide and not very 
tall or deep.

There aren't a lot of them around, but there are a few on the air.

FWIW, I still have somewhere several of the MF antenna loading units NOS.

In a message dated 9/6/2007 9:50:22 PM Central Daylight Time, 
bluebirdtele at embarqmail.com writes: 
> Hi:
>  Picked up a GP 7 transmitter tuning unit (6-9 mhz) at a recent hamfest.  
> Looks good for harvesting hv transmitting parts.
>  Can someone fill me in on the GP 7 transmitter. Don't know a thing about it 
> and no references on the web.
>  Tnx
>  Greg
>  WA7LYO
>  Kinston NC
> 

Robert & Susan Downs - Houston
<http://www.wa5cab.com> (Web Store)
MVPA 9480
<wa5cab at cs.com> (Primary email)
<wa5cab at comcast.net> (Backup email)
   
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