Hi Stefan,

On 11/20/18 6:50 AM, DK7FC wrote:
> Don't waste to much time, it is now the best time in the season! Do you 
> have a second PA, maybe a QRP version? Still worth to try!

No, because I had an attack of stupidity. ;-) Instead of saving my
old PA, which would be 3 or 4 dB down from the new one, I took it
apart to experiment with the design. My idea was to upgrade and
modify it to create a spare PA that could be almost equal to the big
one. Seems the idea was OK. :-) But for many reasons I did not
continue that project. I will look around for the box which contains
that project, maybe I can easily put it back to its original form...
if the cat didn't find the box and take too many parts!

> Maybe you can run a permanent carrier and reach negative R values then? 
> The world's energy problems will be finally solved! ;-)

Hmm, then I will be rich and famous or just famous?
Or neither and remain infamous? ;-)

> Depends on how you measure the current. A saturating current transformer 
> will become warm or hot. Should be easy to check.
> Or it is an iron dust core thermally drifting away. It is useful to 
> measure the voltage behind the LPF.
> Just some spontan thoughts.

OK, thanks for the ideas. I did notice last night something
interesting on MF. The phase was changing slightly during each TX
period. Something to note is that on MF, the coax to the antenna is
almost exactly 1/8 lambda electrical length. So any change in
antenna R shows up mainly as a change in phase at the transmitter.

So it may be that something in the antenna is changing R on MF also
(with only ~75 watts RF). It's a completely different coil and
transformer so what could it be. I don't know.

Maybe I am cooking trees? Just joking. It will be some engineering
defect in my RF systems. Good news is there is plenty of snow now,
so any fires around the antenna should be slow to spread. :-)

73,
Paul