K2: Tune For Low SWR or Max Power?

Posted by jperelst on Dec 25, 2010; 10:12am
URL: http://elecraft.85.s1.nabble.com/K2-Tune-For-Low-SWR-or-Max-Power-tp5866142.html

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
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html