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Re: [TowerTalk] elevated short vertical dipole or quarterwavemonopole?

To: "Towertalk" <>
Subject: Re: [TowerTalk] elevated short vertical dipole or quarterwavemonopole?
From: "Al Williams" <>
Date: Sat, 4 Dec 2004 09:43:10 -0800
List-post: <>
----- Original Message -----
>.  Did you ever contemplate where the difference was coming from?
> Ground losses?

I have difficulty in understanding or accepting the notion of "ground
losses--...wasted power heating the earth, etc..."
I have no problem with using a dc, ac, or rf resistance meter to measure
between two earth points, but radio waves striking the earth, I dunno!
What follows is what is puzzling; maybe someone can help answer them.

1.  Radio waves from a horizontal antenna striking the ground are
reflected (exactly what is going on by reflection?) and add signal
strength to the skyward wave.  However radio waves from a 1/4 wave
vertical striking the ground are  absorbed (all? partially ? and as a
result do not provide the ~2 db gain of a dipole and the ~ 4 db gain
from ground "reflection".

2. The horizontal dipole radiates because each half of the dipole
alternately charges and discharges oppositely and equally.  But what
goes on when the feedpoint is moved off center so that metal to charge
on each side is unequal?

3. The 1/4 vertical alternately charges the vertical portion against the
ground (or ground wires, salt water).  Therefore is the problem not that
the ground is lossy but rather that the vertical part of the antenna
cannot be charged as well it is over metal wires or salt water?  Has
anyone measured the power going into the vertical part when over ground
vs when over wires or salt water?

4. Is the "ground loss" frequently referred to related or confined to
the Brewster angle consideration?

5.  Again, what is actually going on by ionosphere and ground
reflection--is it similar to metal interception radio waves and becoming
a generator?



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