[TowerTalk] antenna impedence and ground impedence??

[Tom Rauch]

> Measuring ground resistance is easy. You just have to make a lot of
> measurements.
> This is how we find mineral veins which we can map based on the
> measurements.
> Any introductory text on geophysical prospecting using potential methods
> will
> teach you all you need to know. The math isn't bad.

It definitely isn't easy.

It is all but impossible for a ham to measure the radiation resistance,
ground loss resistance, and antenna loss resistances. Even broadcast
stations are forced to back the data out of many dozens or hundreds of FS
measurements in a proof of performance. Even with a full proof and careful
work you are lucky to be within 3dB.

I don't know what you are measuring, but accurately estimating the portion
of resistances normalized to one point in the system from antenna loss
resistances, radiation, and ground losses so you can estimate efficiency is
all but impossible outside of a complex test environment. This is what he
wanted to do, not to know the DC or low frequency AC soil resistance between
two or three probes.

With enough measurements we can learn the average low frequency
characteristics of soil, but that data doesn't mean anything in this
application. Neither does a meter at the antenna feedpoint.

73 Tom