[Elecraft] K2 key clicks

[Vic Rosenthal]

Barry Simpson wrote:
> 
> What I found was that if I run with the power control at maximum there
> are quite noticeable key clicks on 160m, 15m and 10m. This is with about
> a 14.8 volt power supply. However if I back the power control off a bit
> the clicks disappear. It seems like either the PA or driver changes from
> linear to non-linear operation at maximum power on certain bands or
> maybe develops instability.

Hi Barry,

This does occur as a result (I think) of overdriving the TX mixer.  The problem
is that when the power control is set for 15w it increases the drive until it
gets it -- and on those bands the overall TX gain is too low to produce 15w.  I
suggest making sure the BPF alignment and RF output detector adjustment are as
spot-on as possible, but you still probably won't get 15w on those bands.

The way to prevent the clicks is to keep the power control at or below the point
that it calls for more power than the K2 can provide.  Before I installed the
KPA100, I found that 13w was the most I could get on 10/12 and 160 meters.

Maybe the real experts will chime in with a better answer!

Vic, K2VCO