Dave wrote:

[regarding elevated radials]

the more and the longer the better of course! . . .

No, that's not true. The efficiency of a vertical antenna with elevated
radials declines noticeably as radial length increases beyond quarter
wave resonance. With half wavelength radials, the efficiency can be very
poor, depending on soil conditions, the number of radials, and the
height. Decreasing the radial length to less than a quarter wavelength
doesn't generally hurt the efficiency much. I'd guess that the
efficiency would peak again at 3/4 wavelength, but I haven't checked.
It's easy to model with EZNEC or similar program, and you can get a fair
evaluation of a system with a few radials using the free demo version.

I should mention that the resonant length of radials is shorter when
close to the ground than it is in free space. This has to be considered
when choosing elevated radial length, particularly if the radials aren't
very high in terms of wavelength.

Roy Lewallen, W7EL