Re: NEC-LIST:old question on non-physical output

Some constraints are not mentioned in the manual.

1. Do not join together segemnts of widely different lengths. About
1.5 to 1 max ratio.
        
2. Avoid co-linear wires, i.e. duplicate wires.

3. Use the average gain facility. On the RP card, I4 is named XNDA.
Set the A value to one, and sweep the theta and phi angles over the
whole sphere. The result should be close to one (i.e. .95 to 1.05).

Wayne Shanks wrote:
>
> I am generating some medium to large antenna files (800 segments)
>
> These antenna are generated automatically from a set of parameters. I
> do my best to make sure that I do not violate any wire rules, but even
> when I think there are no violations, I get strange results.
>
> For instance I may get negative port Z, or negative efficiency, or
> greater than 100% efficiency.
>
> sometimes I will have a reasonable feed Z and good efficiency, but the
> radiation pattern data is all -999.99 dB, Or the efficiency is ********
>
> Perhaps NEC4 is more forgiving of small segments, or maybe I just need
> to look into wire rule violations more.
>
> How should I interpret these strange simulation results?
>
> Wayne S
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Steve Inge, ZL2BDV, RF Engineering Analyst. Island Bay, Wellington, New
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