Thanks to the replies – here and direct...
preface my responses with this statement: although I can reply to these as I
have below – that doesn’t mean it is definitive although checked as stated ...
obviously whatever is wrong I’ve not yet found.
replies:
-The only problem with a ground association is that the effect is the same
whether it is 8' up or 37' up number one that obviously would not be the case
in the real world – we’re talking 3/4 wavelength at 15 meters - and second and
most important - the first antenna showed absolutely no ill effects from rain.
-Nothing is different from this antenna to the other. And again: the other
antenna was rained on when it was up for testing – no change whatsoever that I
remember.
-near field would be a good start – but there isn’t anything there, the other
antenna had the same ‘near field’ ... and rain sure shouldn’t change any thing
nearby in the nearfield (‘move’ metal)...
-although I’ve not checked otherwise I found it hard to believe this could be
water ingress into coax – it would not clear that fast and repeatedly.
I’m going to have to take it down and move the testing of this antenn to 2 1/2’
above ground on a saw horse. I’ve got to move on with the 5el20 testing. Up
until now the testing has gone quite well ... just need to get this dumb thing
sussed out.
I’m happy to hear Noalox isn’t the problem. I do have a rivet at each junction
to augment the 2 through bolts used by the manufacturer.
Gary
From: George Dubovsky
Sent: Saturday, April 2, 2016 8:33 AM
To: StellarCAT
Cc: tower
Subject: Re: [TowerTalk] frustrating rain and connections... also Noalox?
Hi Gary,
I'd look for things that are different, like the coax or balun connections. And
I've never had any issues with brand-name NoAlOx in joints, either new or years
later.
73,
geo - n4ua
On Sat, Apr 2, 2016 at 8:21 AM, StellarCAT <rxdesign@ssvecnet.com> wrote:
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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