You will want to visit L.B. Cebik's site: http://www.cebik.com/
There is little left to be said about modeling after you plow
through all that he shares there! ;-)
- 73, DavidC K1YP
************************************************************************
> Anyone have any experience to share modeling LPDAs?
>
> I'm trying to model my T10 using NEC4WIN, and I'm having
> what looks like ill-formed matrix problems. Granted, there are
> a LOT of segments - LPDAs have a lot of 'wires' since
> the boom is hot - I have 39 wires @ 4-10 segments each.
>
> When I graph any quantity (gain, f/b, swr) over a frequency
> range, I get mostly smooth curves, but every so often
> I get a very sharp spike off the chart. (This is in free space)
> I've tried twiddling everything, from wire size to
> # of segments, etc. Also the feed impedances don't seem right.
> The azimuth pattern _does_ look good, and apart from the
> sharp spikes the average numbers for gain, f/b, swr look good.
>
> Have I hit on a limitation of NEC4WIN? Past a point, the
> results don't change as I increase the # of segments, so I
> don't think it's a resolution problem....
>
> Tnx & 73
> Len K1NU
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