[TowerTalk] Impact of high water table levels on antennas

[Jim Lux]

On 11/3/13 3:37 PM, john at 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