Topband: Good soil vs bad soil

[Tom Rauch]

Hi Greg,

> I used the ARRL Antenna Book method, but noticed on the diagram that the
> cold side of the AC supply is grounded.  Surely that affects the results
> quite seriously, or am I missing something?

That's the least of the problems Greg.

What is measured at 60 Hz (or 50 Hz) has almost nothing to do 
with how the soil behaves at 2 MHz. The skin depth on 160 meters 
can be as deep as 30 feet or more. The ground rod measurement 
might give you the resistance of a two inch layer of good soil, when 
the rest is soaking up RF like a sponge.

You'd be better off to look at a chart from a local BC station, since 
there isn't any effective way to measure soil characteristics short of 
measuring the slope of attenuation of a ground wave signal passing 
through the site under question.

There are some test instruments that measure the soil at radio 
frequencies, but the instruments are not very common and still 
require verification from multiple measurements.

It's a shame the Handbook keeps that misinformation in publication.


73, Tom W8JI
w8ji@contesting.com


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