"Gene Fuller" wrote

Whether this is "resonance" I cannot say. However, it is pretty
clear
they understood that the radial currents did not monotonically
increase
as the distance from the antenna decreased. There was some sort of
variation.

Their figure 42 seems to show significant "resonance", but there
does
not appear to be any discussion of that behavior.

==========================================
I find it easier to think in terms of ground currents flowing 'away'
from the focal point rather than coming into it.

At 3 MHz, where BL&E made their measurements, in ordinary soils there
are hardly enough resonant effects to be noticed. At MF and below
there are no resonant effects. The equivalent transmission line is
mainly resistive. There is inductance of the radial wire but
propagation is largely independent of the value of soil permittivity
and hence on 'capacitance'.

Resonance effects begin to show at 7 MHz, At 21 MHz permittivity and
inductance predominate - especially with high ground resistivities.

At higher frequencies in very high resistance soils, buried radials
take on the characteristics of the elevated variety. But nobody uses
buried radials with vertical antennas at 30 MHz and above. Everybody
switches to dipoles!
----
Reg.