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Re: [TowerTalk] Impact of high water table levels on antennas

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Impact of high water table levels on antennas
From: Jim Lux <jimlux@earthlink.net>
Date: Sun, 03 Nov 2013 16:31:56 -0800
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
On 11/3/13 3:37 PM, john@kk9a.com wrote:
I do not think fresh water has much effect on verticals and even less on
horizontal antennas.


depends on how much water and how deep. That epsilon of 80 for water makes a huge difference.

If nothing else, it will reduce ground losses. Remember that "skin depth" at HF in soil is many meters, so if you have a very highly reflective layer (either by high epsilon or high sigma) a meter below the surface, that helps.

http://www.antennasbyn6lf.com/files/ground_skin_depth_and_wavelength.pdf
has the equations

but, at 4MHz,

f       mu      sigma   eps     skin depth (m)
4       1       0.005   10      4.42
4       1       0.01    10      2.81
4       1       0.1     10      0.80
4       1       0.005   5       3.97
4       1       0.005   3       3.80
4       1       0.005   80      9.59
4       1       0.01    80      4.92
4       1       0.1     80      0.87


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