Tom, W8JI wrote:
"The common Eznec programs use NEC-2 engines, and there is considerable
question about accuracy of models with conductors near earth."
==========
In a comparison test I did a year or so ago, the results of EZNEC3 and
EZNEC4 (which uses the NEC-4 engine and can model in-ground radials) were
compared. In EZNEC3, the radials were modeled slightly above ground and
in the NEC-4 program, they were modeled on (in contact with) the ground.
I was surprised at how closely the two programs agreed on patterns and
gain of the same antenna.
In EZNEC3, the high accuracy Sommerfield-Norton ground model was used and
in the program with the NEC-4 engine (modeling was done by the editor of
the ARRL Antenna Book, Dean Straw, N6BV), the high accuracy ground model
was used.
Therefore, if EZNEC3 (which uses the NEC-2 engine) was inaccurate, then
so was the program that used the NEC-4 engine.
73, de Earl, K6SE
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