I'm not sure but the possibility exist that the electrical size of your
elements increases (getting thicker) due to collection of rain drops. As an
element has to be slightly shorter if it is thicker (larger diameter)
collected water on the outside of the elements should have a similar effect.
The fact that the SWR shifted to a lower frequency support that.
Hans - N2JFS
-----Original Message-----
From: StellarCAT <rxdesign@ssvecnet.com>
To: tower <towertalk@contesting.com>
Sent: Sat, Apr 2, 2016 8:21 am
Subject: [TowerTalk] frustrating rain and connections... also Noalox?
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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