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[Antennaware] Re: NVIS -- modeling, mininec vs nec-2 disparity

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Subject: [Antennaware] Re: NVIS -- modeling, mininec vs nec-2 disparity
From: (John Kaufmann)
Date: Fri, 7 Jun 2002 09:51:40 -0400
Pete Smith wrote:

> I'm not sure how much of the context was on the reflector, so let me just
> add a little.  The same model, with NEC-2 and Sommerfeld-Norton ground,
> shows a VERY different result.  Instead of peak gain being at the zenith,
> it is at 41 degrees and maximum is only 5.99 dBi.  With what EZNEC calls
> MiniNEC ground, results from NEC-2 are close to those Guy reports from
> AO.  Since doubling the number of segments produces very little change in
> these results, I presume they represent good convergence.

> The question is, which modeling result is closer to reality?

I would not trust the MiniNEC ground model with horizontal wires close to
ground.  "Close" means under a height of .2 wavelengths.  The
Sommerfeld-Norton ground model is reported to be reliable, however, for
horizontal wires down to a height of about .001 wavelengths.  I  believe
this is all covered in the EZNEC user documentation.

73, John W1FV

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