[Elecraft] K2: Tune For Low SWR or Max Power?

[Jon Perelstein]

I'm running a K2 (with KPA100) with an MFJ941E Versatuner.

My antenna is a multi-band Windom that will load up on 80, but is less than a 
half-wave on 80.  On most bands, lowest SWR per the tuner coincides with the 
highest output power showing on the K2 (usually 20 or 21 watts).  However, when 
in TUNE mode in the CW portion of 80, the lowest SWR per the tuner shows a 
reduced power output per the K2 (about 16 or 17 watts).  In that portion of 80, 
I get the maximum power output showing at about a 2.5:1 SWR per the K2.  The 
readings on the tuner's forward and reflected power meters are consistent with 
what the K2 is showing, with a noticeable dip in forward power when I get 
minimum SWR.

Receive signal strength is also consistent with what the K2 is showing.  By ear, 
received signal strength is lower at the minimum SWR point than at about a 2.5:1 
SWR setting.  Similarly, the K2's S-Meter shows that the received signals are 
about 1 S-Unit lower at lowest SWR than they are when I tune for that 2.5:1 SWR 
setting.

I understand that this antenna is not "optimal" for the lower stretches of 80, 
but given that it's all I can put up at the moment, am I better off tuning for 
the best output power or for the lowest SWR?  If I tune for the best output, how 
much should I back off on the output power to adjust for the fact that I'm 
getting more reflected power coming back into the rig?

Thanks

Jon
KB1QBZ