[TowerTalk] Change in SWR

[Rick Stealey]

Doug, 
I'd like to suggest something to try.  I haven't actually done this but it might bring results, and won't cost you a dime, or even get your feet or fingers cold, no matter how cold it is at your QTH.

Your low dipole, MAY be coupling to the yagi, that's the concern, right?  And if so, if you detune it, the amount of interference would change.  So my idea is to NOT go out to the antenna feedpoint and do anything but rather to put variable impedance across the feedpoint of the low dipole in the shack.  Use an antenna tuner, and tune it through every impedance you can, all the way from a short to an open and everything in between.  These impedances will be transformed to some other impedance at the feedpoint of course.  The objective is just to see if ANY impedance will cause any change in SWR.  If you see any effect whatsoever you know there is some amount of coupling and you can take it from there.  But right now I believe your concern is whether the new dipole is involved in the SWR changes, and this technique should answer that question for you.

Rick  K2XT