[VHFcontesting] Harris amp on 222

[N1BUG]

I have one of the Harris channel 11 amps which I use on 222. I have been 
somewhat disappointed with it. A friend bought one from the same source 
and reported it would do 1100 watts out (He backed off and ran it at 
less, I think). Mine maxes out at 800W out with 45W drive. It will not 
do any more no matter how hard it is driven. That is with 51V under load 
from a power supply that is more than capable. I haven't been able to 
find the reason why mine is so much lower than another. I will add that 
as received the bias was *way* off on some of the FETs. I went through 
the bias setting procedure per the Harris manual but it did not get me 
any more output. Some of the quarter modules run cooler than others. I 
think they are just tired and need new FETs. The efficiency is the same 
as you are seeing: in my case 1800W input for 800W out.

73,
Paul N1BUG


On 4/18/20 7:13 AM, mike repinski via VHFcontesting wrote:
> Has anyone tweaked a channel 11 amp for 222 mhz?  I am using 2
> modules in parallel. With 30 watts drive I am seeing 18 amps at 50
> volts input. That would be 900 watts input. I am getting 400 out. Not
> very efficient. It makes a little more at 220 than 222. Thanks Mike