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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