[Amps] Thinking out loud

[Vic K2VCO]

On 4/21/2010 1:12 PM, Carl Clawson wrote:
>
> I run a pair of grid-driven 813s, actually a number of pairs. See the
> "single band kilowatt" in ARRL handbooks from the 60's, may also be there in
> late `50s. Plus, the article's available to members on the web site.

A classic!

> Recently I added a 6 dB pad on the input, so it drives in class C with 40 or
> 50 W. This was to keep my exciter power away from the threshold where the
> Elecraft K3 switches to its 100 W final amp, which made the power adjustment
> too fiddly. You could do that to limit the input, but make it more like 8 or
> 9 dB. Drive will undoubtedly depend on the band so set it for the highest
> drive you'll need and you'll never go dangerously far over. I used Caddock
> MP9100 series resistors on a nice hunk of surplus heat sink.

Excellent idea. The pad will also reduce the SWR to the exciter.

Thanks, this is simple and will make my life easier.
-- 
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/