Yep,
Quite a few of us here in VK6 run the TMC amp based on the PL172.
The tube is actually the Eimac 8295A ceramic pentode. The part we use is
the Intermediate power Amplifier stage of a much larger transmitter.
We run 3200V on the Anode, 500V on Screen, around -110V on the Grid and 0V
on the suppressor. The specs say to run +35V on the suppressor grid but the
socket has it grounded so it is a little difficult to achieve Hi hi.
We run it in AB1 with a 50 Dummy load capacitively coupled into the grid.
100W drive gives us more output than we are allowed here in VK.
The original chassis has a 6cl6 followed by a 6146 driving the 8295. We
ripped all that out and just used the final tube as described.
The transmitters are still in use today at WWV. Have a look at their site
for the pics. You can see the part we use located in the middle section of
the transmitters.
If you need more info, just give me a yell on 20m. I am on most days around
14.257 at 2145 -2300 UTC beaming long path US using that amplifier.
73, Merry Christmas to all,
Alek. VK6APK.
At 09:17 AM 12/24/98 -0500, you wrote:
>
>Hello all:
>
>I just saw an Ad for a military Technical Material linear that uses a
>PL-172 or 8895 tube. Ad says 1KW output, continuous tune from 2 to 28
>MHz, Key down all day on AM. 4' high rack mount. Anybody heard or know
>of such an animal? Is a PL-172 equivalent to anything from Eimac?
>
>Thanks..
>
>'73 KI4Z
>
>
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