On Thu, 02 Sep 2004 03:53:46 GMT, "GW"
wrote:

I have a question similar to but different from the one posted a few lines
below. How do you determine the quality of an antenna ground at HF on an
absolute basis? Not how well have I maximized what Mother Nature gave me at
my QTH by adding radials, but how good is my ground compared to other
stations' grounds at other locations? I have read about the advantages of
seawater, ground conductivity etc as guidelines, but how is overall ground
quality (not just soil resistivity) determined objectively if indeed that is
possible at all?

Hi George,

You compare a measured value with the theoretical, the difference is
loss. Less loss = better (objective goal expressed subjectively).

To state the objective goal objectively, you describe the difference
in dB. However, this quickly devolves to a subjective test, because
only your contact can appreciate the difference, and too often the
difference is less than many other factors of variability (like
fading).

So, let's put this in objective terms. With a dozen radials down, you
could double or quadruple that to achieve 2dB more power out. 2dB on
the conventional S-Meter may barely register more than a needle's
width change while your signal is otherwise dropping and rising 10dB
through a QSO. Go the limit (theoretical of course) of 120 radials
and you perhaps achieve 3 to 4 dB or two needle's widths.

Another objective test is to measure the resistance and compare it to
theoretical. However, take care to observe that theory covers a lot
of ground (no pun) principally depending upon the thickness of the
radiator. To take a useful and common indicator, that value would be
36 Ohms. If you measured 50 Ohms, the excess 14 Ohms could be thought
to be residing in poor connections and the loss of ground. You would
then tighten connections and add radials to shield against ground
loss. Hence by these actions, resistance would lower, and oddly (that
is, in contradiction to misguided expectations) SWR would rise. It is
unlikely you will add enough radials to achieve theoretical, but close
enough counts in RF, hand grenades, and H-Bombs.

It is called the law of diminishing returns (a business concept) where
the more you put into the ground is not matched in continued, improved
performance. It is the first few that count the most.

73's
Richard Clark, KB7QHC