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Tue, 13 Nov 2012 21:41:01 -0500 |
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I'm pretty sure that antenna impedance will be the most affected for
antennas less than a quarter wave above ground, and will go up and down in a
damped sinusoidal pattern as it is raised further. You would probably need
to be up 3 wavelengths or more to have minimal interaction. If you're
talking about radiation angle, it is most affected if the ground is very
conductive. As you get higher than a half wavelength above a conductive
ground, you begin to develop lobes and nulls in the elevation pattern. If I
had some time, I would obtain a copy of EZ-NEC or a similar program and see
if I could read any of its output.
-----Original Message-----
From: Dave Marthouse
Sent: Tuesday, November 13, 2012 12:39 PM
To: [log in to unmask]
Subject: Antenna Interaction
Hi Gang,
I should remember this but I am putting this theory question out to the =
group. What is the minimum altitude when an antenna stops reacting or =
interacting with ground? Is it a half wavelength or a full wavelength? =
Naturally for the purposes of this discussion I am leaving out ground =
mounted verticals. It has been a while since I visited this segment of =
antenna theory. Any info is appreciated.
Dave Marthouse N2AAM
[log in to unmask]
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