NEC-LIST: Re: NEC 4.1 Anomaly

I see this with NEC4S compiled with CVF. My guess is that it's an
accumulation of error. I don't see it with NEC4D, or with EZNEC/4 which
uses its own double precision helix creation routine even when NEC4S is
selected to run calculations. If you need to use single precision NEC4,
it would probably be a good idea to rewrite the helix subroutine in
double precision.

Roy Lewallen

Frank wrote:
> I have been trying to model an inductor in NEC 4.1, (code shown below)
> single precision (NEC4S600). I have observed a disconnect of 55
> micro-meters between segments 300 and 301 -- which is treated as an open
> circuit (>0.001 of a segment length at 44 micro-meters).
>
> Changing the number of segments, or the number of turns, by one or more,
> corrects
> the problem. Typically the segment end-points are within < 3 micro-meters.
> I have not identified all conditions when this occurs, but some other
> combinations
> of segments, and turns, do produce a disconnect. I have not completely
> investigated NEC 4.1, double precision, but it does run the code below with
> no disconnect evident.
>
> I have used Excel to compute the segment end points from the NEC output
> file.
>
> I would be very interested if anybody else has observed such an anomaly.
>
>
> Frank Meredith
>
> CM Inductor Calculation (NEC 4.1)
> CE
> GH 1 300 15 12 6 6 0.02015 0.02015 0
> GW 2 3 6 0 12 0 0 12 0.02015
> GW 3 6 0 0 12 0 0 0 0.02015
> GW 4 3 0 0 0 6 0 0 0.02015
> GS 0 0 0.025400
> GE 0
> EX 0 3 3 00 1 0
> FR 0 5 0 0 3.7 0.02
> LD 5 1 1 312 5.7001E7
> RP 0 181 1 1000 -90 90 1.00000 1.00000
> EN
>
>

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