The definition of a good ground depends on the purpose for which it is needed/used.
An a-c ground reference using one (or several) buried "ground rods," when properly configured and installed, may be sufficient for useful protection from nearby lightning discharges for the electronic systems using them.
But for average soils, such buried rods are not very useful as a ground reference to maximize the radiation efficiency of a Part 15 monopole antenna system using medium-wave radio frequencies.
Rich said: "An a-c ground reference using one (or several) buried "ground rods," when properly configured and installed, may be sufficient for useful protection from nearby lightning discharges for the electronic systems using them."
I said: " True. The grounding system for lightning protection that was installed at our LPFM antenna location was a Delta system consisting of three 20 foot ground rods that were cad-welded to #2 solid wire. The measured resistance was less than 5 ohms.
The measured resistance was less than 5 ohms.
At what frequency or range of frequencies was that measurement made?
This ground system was for lightning protection not for antenna enhancement. The measuring device was a Megger DET4.