I came back from vacation to find my 20 meter stack not working right. To
make it short, the bottom stack 100/50 is fine, SWR is the nominal
1.2-1.5. Of course if one part has to go, it is the top one.
The top stack, 200/150 is the problem. Directly connected at the base of
the tower the SWR is around 3.5 and drops to around 1.7 at around 15.6 mHz.
I have not gone up the tower yet to check it out hoping to get a couple
of suggestions before doing so. Physically, from the ground, the antennas
look fine, and with the SWR at least getting near a "normal" reading, even
if out of the band, I think the baluns are good. The antennas are M2 with
1:1 baluns.
I do have a phasing harness made up of a tee-connector with two 1/4 wave
75 ohm matches leading to the two antennas as well as a couple of a other
coax connectors. My hope and thinking is that perhaps one of these suffered
some water intrusion even though they were pretty well waterprooofed.
Since I wasn't home, and we did have t-storms, lightning could also be a
source
of the problem. By the way since the antennas do have baluns I checked
the resistance and it was about 1 ohm....pretty much what you expect, but
that could be due to a short on the line.
Any ideas before I climb? I plan to take my trusty MFJ259 and a
multimeter and check all connectors that I can reach.
Bill K4XS
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