Problem is that loss is proportional to signal frequency through the
earth, A low audio tone is much more appropriate. With a low audio tone
on an insulated conductor buried in the earth with reference to a ground
rod or ground bed, the conductor can be traced for miles. I`ve traced
4-ft. diameter poorly insulated steel pipelines for 8 miles or more and
they were buried several feet down for protection.

Thats a suggestion that I would have liked to have tried. I have the
generator, and could have easily fabricated a "receiver". Oh well.
Another technique to add to the repertoire !

Ed K7AAT