From: WarmSpgs@aol.com
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Date: Mon, 16 Dec 2002 16:32:01 EST
To: rsgb_lf_group@blacksheep.org
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Subject: Re: LF: EARTH RESISTANCE
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In a message dated 12/16/02 1:30:09 PM Eastern Standard Time, 
g3kev.ham@virgin.net writes:

<< Dick has indicated that Earth Resistance gets higher when the ground is 
wet. That seems strange and contrary to accepted theory. The ideal ground 
plane for a vertical is on a wet plain or preferably positioned in the middle 
of a lake or in the middle of the Ocean. Have I missed something and read his 
observation incorrectly. >>

I think both points of view are correct, but under differing prevailing 
conditions.

The type of soil may make a great difference in whether moisture enhances or 
degrades radiated signal.  Where I live now, the soil seems to experience 
increased dielectric loss when wet; whereas, in other locations, I found the 
opposite to be true.  Because of the greater skin depth of the earth as the 
wavelength increases, I would expect the effect to be more pronounced at LF 
than MF or HF.  Dick's data may be partial supporting evidence that this is 
so; in which case, it's even possible that some soils will be better at MF 
when wet, and better at LF when dry.  Sounds like a fertile field for 
investigation (no pun intended).

As for bodies of water, a freshwater lake turns out not to be as good a 
location for a ground plane as I once thought.  I have tried this approach at 
LF and MF at a few very different locations, always with less signal than 
expected.

Seawater is quite a different matter!  At MF, especially, it does truly 
wonderful things for signals.  Along with our fleet of VHF FM public 
broadcast stations, I oversee one small mediumwave station on the Georgia 
coast which is less than listenable more than about 20 miles inland.  
However, it has a coastal coverage range from St Augustine, Florida, to 
Hilton Head, South Carolina.  (In fact, do we have any readers in Bermuda?  
If so, I invite you to give a listen on 1190kHz.)

John