Richard Fry wrote:
"So it`s not just the number of radials that is important, but also
their length."

True. I don`t have B.L. and E`s work to refer to but do recall an
observation that to get the best ground connection for the least copper
it might be wise to cut the radials in half so that their number might
be doubled.

The FCC standard is 120 radials, each 1/4-wavelength long, which may
seem extreme but it produces a near perfect ground connection.

Fortunately, the length of radials does not need to be increased in
direct proportion to wavelength below the broadcast band as skin effect
varies with the square root of the frequency so as we go lower in
frequency we need to increase length of the radials by the square root
of the wavelength to keep the resistance of our contact constant.

Best Regards, Richard Harrison, KB5WZI