[TowerTalk] Stange SWR/AttenuationpProblems, goes away when the sun comes up

[Gene Smar]

Rich:

     I suggest checking the ground block you identified throught the link, 
below.  As I mentioned in our private e-mail, it's difficult to seal these 
things at the connector/plate interface, especially the upper connector, and 
moisture may have bewen wicked inside one of the PL-259's.


73 de
Gene Smar  AD3F


----- Original Message ----- 
From: "Richard Thorne" <rmthorne at att.net>
To: "Towertalk" <towertalk at contesting.com>
Sent: Sunday, April 01, 2012 11:01 AM
Subject: [TowerTalk] Stange SWR/AttenuationpProblems,goes away when the sun 
comes up


>I finished my tower/antenna install Friday.  77' of 45g with 15' of mast
> out the top.  I have a F12 D240 mounted 10' up the mast and a F12 C31 at
> about 1' up the mast.  The swr is where they are supposed to be on both
> antennas.
>
> Now for the strange part.
>
> Some time after dark my D240 becomes attenuated and the swr is very very
> high.  But after the sun comes up for about 2 to 3 hours, the
> attenuation goes away and the swr is right where its suppose to be and
> signals are clear and strong.
>
> Its been clear with no rain since the antenna has was put up Friday
> morning.  There must be some moisture in the air as dew does form on the
> grass and the roof of my steel building/shop.
>
> So I'm scratching my head on this one.  I've switched out coax cables at
> the shack, bypassed the polyphaser lightning suppressors, used the
> different antenna inputs to my Elecraft K3, checked to be sure I didn't
> have a receive antenna selected on the K3 etc.
>
> I have a single 158' run of coax from my entrance panel to the top of
> the tower and have it terminated with one of these
> http://www.dxengineering.com/Parts.asp?ID=3320&PLID=105&SecID=94&DeptID={DBD52E00-E4FA-4BB0-A7B9-1EDCD8FCDE17}&PartNo=DXE-CGB-150
> then another length of coax that forms the rotor loop, goes up the mast
> then to the f12 balun (f12 B1) at the feed point of the D240.  I have
> the same setup via another coax cable going to the C31XR which doesn't
> exhibit this strange problem
>
> I have two weep holes drilled in the bottom of each trap cover for
> moisture to escape.
>
> All connection points are weatherized using 3m rubber splicing tape
> which is then wrapped with Scotch Super 33.  All coax, connectors etc
> are brand spanking new.
>
> The next step is to climb the tower and check the connections at the top
> of the tower, if that's not the problem it will be time to bring out the
> crane again and check the connections at the feed point.
>
> Before I get to far into this I'd like to know if any else has run into
> this symptom and what the final resolution was.
>
> Thanks
>
> Rich - N5ZC
>
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