[Milsurplus] AT-12 Photo

[Hubert Miller]

I'd read, in SPRAT i think, of some Brit fellow who was running a T-1154  aircraft transmitter with lower voltage for QRP operation, so i was aware of that option.
I have an ATD also, which uses the same 814, and the fellow i bought it from, back around 1976, told me he powered it up with something like 150 volts on it,
just "proof of concept" i suppose. So it is possible to run the AT-12 on say, 650 volts or so, something i could build without too much difficulty. However, thinking
about the 2x 32.5 watts inside, just to heat the tubes.....!!!   Anyway, i have lots of time to think about it....lots to downsize before i start any new project.
-H 

-----Original Message-----
From: Milsurplus [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of Richard
Sent: Wednesday, March 8, 2017 12:53 PM
To: milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] AT-12 Photo

The 814 has a small 5-pin base, the same as an 807, so it's an easy change.  However, the 814 is a beam-power tube, which is not so sensitive to plate voltage, and will probably work fine down to 500 volts.  Overall efficiency will not be great when you're putting 32.5 Watts in each filament.

Richard, AA1P