Had a few good ideas about how to determine why my new interlaced 5 el 10/5
el 15 yagi was a poor performer. This afternoon I rotated the antenna on
the mast 90 degrees so it is at a right angle to my 20/40 interlaced yagi
that is 14' above it..
Well the results are nothing short of AMAZING. The 15M antenna now performs
like the 10 (when comparing to the A3 reference antenna 20' down the
tower). Where I used to see little/no difference between the A3 and the 15M
antenna I now regularly receive reports of " 2 S units better" for the 5
element. I'm not sure if it was the 20M or 40M antenna (or both) causing
the problem - but the improvement seen via F layer skip (and ground wave)
is in the 6-10 dB range, depending on what you think an S unit is.
The SWR changed VERY little - was about 1.5:1 and now 1.3:1. So in my case
looking at SWR. SO all you guys with stacked antennas out there don't just
believe that good SWR means no interaction. I strongly suggest you have
some type of reference antenna to test against. I never thought I would see
much of a problem with 14' spacing from the 10/15 to the 20/40. But it was
there in a big way and was, I'm sure, there with my previous 15M antenna.
Now if I can just try and figure out a way to keep the 90 degree offset
straight...
73
Jeff N5TJ
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