Gary, it could be an antenna issue or a feed line issue. I suggest you
temporarily dangle a new coax line from the feed point down to the ground level
and make a test to determine which it is.
Perhaps you have a method of checking the SWR right at the feed point with
a remote readout?
Happy hunting!
Gerald K5GW
In a message dated 4/2/2016 7:21:54 A.M. Central Daylight Time,
rxdesign@ssvecnet.com writes:
I’m testing a yagi... I can raise it to ~37’ for testing and lower it to
about 8’ for adjustment ... it was made as a duplicate to another one and
testing showed it to be just that – a duplicate. Until it rained! The SWR
shifted downward. At 21425 it was ~1.35:1 ... and it would go over 2:1. I’m
at a loss as to what is causing this. It is a used antenna reassembled...
but I find it very difficult to believe that water could get in to the
mechanical joints and cause this kind of a problem. The balun doesn’t appear
to
be taking on water – there wasn’t a drain hole in the bottom – there is now
– I went out early this morning just after it rained – SWR up high – and
there was nothing coming out of the drain hole. I have checked all
connections – they’re tight. Oh – and the strange thing – it goes back to
normal
after only about 4 – 5 hours without rain. It has done this 3 times now. It
is now – 45 minutes after checking it this morning where it was at 2.33:1,
its now down to 1.8:1 and continuing its decent. And further note the SWR
seems to be about the same – its just shifted downward when wet. Also I
hosed it down – the balun/coax connection, hairpin for a good 5 minutes – no
change. I hosed down the elements at their joints – no change. It rains:
changes! The fact that it shifts seems to be independent of height – it does
this if at 37’ or at 8’.
Also: is Noalox the same as penatrox? It is the No AL OX sold by HD ... it
says it is for increased conductivity as well as anti-seize... perhaps IT
is the problem at the joints ... unless someone knows it to be fine (or
KNOWS it to be bad).
thanks – I’m hoping someone has personally seen such a thing and has an
idea. Its holding up the testing of the other antennas.
Gary
ps: the first one had no problems when it was rained on.
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