Here in the U.S., the simplest way to get an estimate of regional
ground conductivity is from the records of a nearby directional
(multi-tower) AM (medium wave) radio station. Their operating
parameters are based on field strength measurements that are
correlated with established ground conductivity curves. I don't know
if there are equivalent field strength measurements routinely made by
European MW stations.
An alternate experimental approximation would be to make a
dipole and measure its impedance at a low height (3 to 5M), then
raise it to 15-20M and measure it again. I was able to determine
that the ground under my antennas is lower conductivity than
expected from broadcast data simply by measuring the change in
resonant frequency (R +j0) at two heights. Select various values
for conductivity in your modeling program until the model matches
the measured data. I use EZNEC with the NEC-2 engine.
> From: "Henk Remijn" <email@example.com>
> To: "Antennaware" <firstname.lastname@example.org>
> Subject: question on ground system for good ground
> Date: Wed, 18 Jul 2001 22:20:52 +0200
> I want to model some antennes but I am stuck with what ground type to
> The place the antennes are is on a place which was before 1850 salt
> since then there is land.
> What I like to know, how can I measure or calculate the ground
> resistance of
> a location.
> Is there somebody around who can help me on this or who can give me some
> good links to info.
> 73, Henk PA5KT
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