Unfortunate I have only a NEC 2 based program (Nittany Scientific's NEC-Win
Pro), but with the Sommerfeld/Norton ground model you can approach the
ground to within 1/1000 of a wavelength closely approximating the results of
buried wires, and in very close agreement with your "RADIALS2" program. NEC
programs do require a value for ground permittivity. NEC 4 based software
is more expensive, being in the $800.00 range, plus a $500.00 license from
the Lawrence Livermore Laboratory. In any case the data are easily compared
with your program results.

I have measured my ground conductivity, but not yet attempted to measure the
permittivity.

If anybody wants to get serious with antenna modeling I recommend Ansoft's
HFSS (Often known as "Highly Frustrating Structure Simulator"). It costs a
mere $30,000, with a $10,000 per year support payment.

Regards,

Frank


"Reg Edwards" wrote in message
...
Frank wrote -
I have also used your software for modeling verticals, and it is
in very close to the results produced by NEC. The one problem with NEC 2
(Though not with NEC 4) is that it cannot model buried radials, but can
get
very close to the ground.

================================

The only program I am reasonably familiar with is the several years old
free
EZNEC. I don't know whether it has been updated or not and I make very
little use of it. Come to think of it, I don't make much use of my own
programs either.

Regarding shallow buried radials in conjunction with a vertical, have you
tried my recent program RADIALS2 ?

It is intended to demonstrate performance of the radials themselves in a
given ground rather than antenna performance. Which I suspect is the
reverse
of NEC-4.

As you probably know, the effects of above-ground radials change very
rapidly as they get within a few inches of the ground surface. But once in
the ground they tend to remain static.

RADIALS2 uses an entirely different, unconventional form of performance
analysis. If other programs don't take soil permittivity into account at
HF,
predictions must lose accuracy. Are the inputs and outputs of NEC-4 in a
form suitable for a direct comparison with my simple program?

But in view of the large uncertainties involving ground conditions,
accuracy
is not worth making much of a song and dance about.
----
Reg, G4FGQ