"Dan Richardson " wrote:

On Thu, 15 Jan 2004 13:02:25 GMT, Andy Cowley
wrote:

You also have modelling programs which don't work.

Can you please provide a list of these "non-working" programs?

Danny, K6MHE

Dear Dan,

dipole3.exe produces very unlikely values for the 'Input
resistance'(sic) of electrically short dipoles. I assumed that
'Input resistance' was the resistive component of the feedpoint
impedance. I pointed this out to Reg and got insults and bluster
but no meaningful reply.

E.g. a 16.6 m dipole at 1.8 MHz h=6m w=1.5 s=120 gives 44.3 ohms.
That seemed a little high to me. So I reduced the length to
1 metre !!!! the resistance rises ????? to 212.8 ohms. Am I
hitting some boundary condition? or am I misunderstanding the
significance of 'Input Resistance'? I'm pretty sure the radiation
resistance plus loss resistance of a 1 metre antenna on top band
should be much less than 1 ohm.

EZNEC gives values at least an order of magnitude less than the
values obtained from dipole3 for the resistive component of the
feedpoint impedance. I believe EZNEC to be a reliable, well proven
program, which gives accurate (at least in this context) results.
The mathematical basis and assumptions of EZNEC and NEC2 are
publicly available, unlike those of Reg's programs.

As far as I am concerned if one of Reg's programs has errors that
he is unwilling or unable to correct or explain then the results
of any of his programs should be checked by a more reliable method
before they are used.

Let the user beware.

vy 73

Andy, M1EBV