Walter,

Your ancient charts, which I think I have once seen but don't now have
ready access to, apply to LF. Permittivity was ignored when they were
calculated. The curves were intended to be used as a guide, better
than nothing, rather than the Bible on the subject.

But amateurs are concerned with what happens at HF. There are a lot of
MHz between 16 KHz, 500 KHz and 40 MHz

I think the discrepancy about conductivity vs frequency is due to
simplification of the equivalent circuit of soil which, in its most
simple form, is a resistor in shunt with a capacitor.

As frequency increases the capacitative impedance decreases and drags
the equivalent resistive component down with it. There is a
significant decrease at around 7 MHz. At 30 or 40 MHz the soil has
changed from being mainly resistive at LF to being mainly capacitative
and not nearly so lossy.

The capacitance between a pair of 1 metre square plates, spaced 1
metre apart, is only 8.8 pF. But when muliplied by the permittivity
of damp soil the impedance at 30 MHz is quite low. The permittivity
of water is 80.

Simple conductivity does not apply. We are not talking about the same
things.

Actually, its not worth arguing about. The uncertainty in soil
characteristics is plus or minus 30 or 40 percent. And it makes less
than 1 S-unit difference to the performance of radials and Eznec take
off angles at HF. No doubt Roy will disagree as a matter of Boston Tea
Party principles. And Richard, KB7QHC, will spin off at a tangent into
Shakesperian verse.

Hope this clarifies my Altzeimer's thoughts on the matter.
----
Reg, G4FGQ