Topband: Ground conductivity, permittivity measurement

[Tom W8JI]

> I don't know about further out where you'd have to proof an AM station
> but I just ran some models and there's kind of a weird relationship
> between vertical electric field strength at 1 wavelength out  and far
> field efficiency as ground conductivity is varied for fixed
> permittivity.

One wavelength is too close to show ground loss changes. You are really just 
looking at radiator efficiency.

The signal has to propagate for some distance on groundwave to show earth 
conductivity effects on signal level.

What I was suggesting is if soil varies from rain as much as a ground rod 
test shows, we should see this change at a distance on groundwave.

BC stations determine soil conductivity by the measured slope of attenuation 
with distance compared to an ideal attenuation slope. I was wondering if 
ground rods were ever correlated to a known way of determining soil 
conductivity.