[TowerTalk] Soil Conductivity/Cell sites from N0AH

[Tom Rauch]

Hi Dave,

> the only real way is to buy, rent, or borrow a meter and measure it. 

The only meter that works is one that measures at the frequency 
you are using. There is no way to accurately extrapolate 
conductivity measured on one frequency to a greatly different 
frequency, since soil is not homogenous. 

Skin depth in good soil is about 25 feet on 160 meters, and nearly 
double that in poor soil. Skin depth is infinite at dc, and near-infinite 
at power line frequencies. It's less than a meter deep at 50 MHz.

What you measure at or near dc has nothing to do with what the 
soil behaves like at 2 MHz, unless the soil is absolutely uniform in 
moisture, chemistry, and composition to a depth of hundreds of 
feet. 

That is why the FCC requires conductivity measurements be made 
near the operating frequency using a test transmitter and antenna, 
by measuring the slope of attenuation of a ground-wave signal.    

.  
73, Tom W8JI
w8ji@contesting.com

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