Topband: Magic Antenna Land

[GEORGE WALLNER]

> "Hugh Valentine" <hsvdds at juno.com> wrote:
>160M inverted "L" antenna...a radial system of 20 >radials, half 33' and half 133' in length and ... an 8' >ground rod into the salt marsh ... and connects the >radials and the Salt water ground Rod together.  
> 
> Should Oval..
> 1) Connect his Ground rod in salt water to his radials
> 2) Use radials only and forget his Ground rod

Hugh,

I don't claim to be an "antenna expert". My observations 
with similar configurations and my intuition suggest the 
following:

a) The capacitance of the radial system to the salt-water 
(saturating the salt-marsh) provides a lower impedance 
path than a single ground rod. Therefore the ground rod is 
not doing much for RF, but it may be useful for lightning 
protection. (Assuming the radials are laid on the ground 
or are very close to it.)

b) If there were multiple ground rods to provide a low 
impedance path to the salt-water, there would be no need 
for the radials.

c) Having both is the best: a 20 radial field is marginal 
and marshes can dry out, etc.

On a number of DXpeditions we mounted inverted L antennas 
standing in salt-water or on salt-water saturated sand. We 
initially installed radials. Often the waves would wash 
away these radials but we could never tell the difference!

I hope this helps,

73, George, AA7JV