[Elecraft] K2 RF Output

[jerry]

All,

   My new QRO K2 behaves a little strangely...

On Tune - it makes 108W on 40M, very nice.

But on 20M it behaves strangely.  It won't make more than 20W or so, 
complains about high SWR. Even though my Heathkit HM-102 SWR/Wattmeter 
says the SWR is zilch.

So I moved it to a dummy load.  As I turn the power up, it makes up to 
about 80W, and then says "Hi CURR".  And it claims that the dummy load ( 
an 800W "Florida RF" resistor bolted to a large heatsink ) is 1.6 to 1, 
which is totally bogus.

OK, there's a null trimmer for the SWR bridge.  I got it down to 1-to-1 
SWR on 20M.  It degrades on higher bands though - up to 1.5 to 1 on 10M.

Now, 20M gives me a max of 45W - above that it complains "HI CUR".  It's 
doing that on all bands.  With the PA off via menu, I get a maximum of 
about 8.5W before getting the "HI CUR" message.  I tried setting the 
current up a little bit on the CAL CUR menu, but no real difference.

   With a clamp-on DC ammeter ( which I don't trust THAT much ) I see 
340mA on receive,
and just about 3.6A when the display goes "HI CUR".  This is with the PA 
turned off.  The
display shows 7W just before this happens.  Hmm, 13.8V times 3.5A means 
48.3W DC input.  Seems a little excessive.

                      - Jerry KF6VB