[TenTec] SWR and Rain

[k8do]

Corn,
Not to be aggressive here and not looking for a food fight, but you are
putting out misinformation...
Window line does indeed have a marked impedence change when wet compared to
being dry... This is due to the change in dielectric constant with the
insulation surface being wetted, not due to the water becoming a dummy load
and absorbing RF... That is pure fantasy on your part... If that were true
we could simply fill a pail with tap water and forego all those expensive
resistors in commercial dummy loads...
If the line is well matched when dry (as mine are) then the swr will rise
when wetted (as mine do), not decrease... I have thousands of feet of window
line in use and I can tell you if the humidity is going up or down by
checking the swr on the antennas...
I agree that well made, open wire, line has very little impedence change
when wetted, because the spreaders have limited surface area, and because
there is not plastic insulation on the line itself, so there is little
change in dielectric constant, and thus little velocity change, and thus
very little swr change... But, that does not mean that there is not a swr
change, just that it is much less than in window line, with all of that wet
insulator surface in the near field between the lines undergoing a change in
dielectric constant when wetted...
I strongly urge that you acquire some instrumentation and perform some real
world testing of antennas and feedlines...

Denny

----- Original Message -----
From: "Sherrill WATKINS" <SEWATKINS@dgs.state.va.us>
To: <tentec@contesting.com>; <holladayfd@multipro.com>
Sent: Wednesday, January 31, 2001 2:28 PM
Subject: Re: [TenTec] SWR and Rain


>
> Frank:  Interesting thought.  However, I once had a home made
> open wire transmission line and no such occurance ever happened,
> even with ice and snow.  If conduction was occuring on the spacers
> because of water, etc. then the swr would go down, not up.  As you
> know, water absorbes rf, which heats it.  This will cause the
> line to act like a dummy load and the swr will go down, not up.  This
> is a mistake that most amateurs assume, i.e. because
> their antenna system has a low swr that everything is ok when just
> the opposite may be happening.
> - 73-s- Corn - k4own.
>
>
> Politicians love unarmed serfs.
>
>
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