Topband: EWE Tweaking

[Michael Sapp]

>Chuck Hutton charlesh3 at msn.com 
>Sun Feb 27 14:00:57 EST 2005 
>•Previous message: Topband: EWE tweaking 

>Somewhere on Mark's site there is data for other antennas  but I don't
>recall seeing anything on EWE's. The situation should be the same: if you
>are in need of the best possible nulls for any antenna that relies on a
>termination to ground, it would be good to have a remote control to tweak
>the termination.
>Chuck

Hi Chuck & Group:  Yes, I have read up extensively on the subject and
agree. A single variable termination would have
made things easier to control for the two back-to-back EWEs, but it looks
like independent terminations is the way to go.
Instead of the Vactrol route (times 2)  I've found another possible
solution. Mouser sells a dual 10K potentiometer with a 3 to 6 VDC motor
drive for about $10. It's made by  Xicon/Alpha and the Mouser part number
is 316-1020-10K. If I parallel each pot with a 2.2K resistor that should
give me plenty of termination value range for each antenna
termination--both controlled from a single motor drive. I may need to pulse
the DC to the motor to slow it down, but that does not seem very
complicated and the controller would be in the shack. I may give this a try
when the snow melts next month.

        Mike WA3TTS