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Jim Lux · September 24th 08, 06:45 PM posted to rec.radio.amateur.antenna

wrote:
Thanks for the effort Jeff, but for some reason it doesn't seem to be
compatible. It won't open as an NEC file and I also tried giving it
just an NC tag. The closest I can get is importing it as a card deck,
but it says it has errors, and when I look at the code, it looks
totally different from other formulas that do work in the app.

Art, it does have variables... I don't know if the segments are
unlimited. It seems to work great with the included files. Normally
I'm pretty good at this stuff. I can do my own html and some other
code stuff, but I'm just having difficulty getting a grasp on this for
some reason. I did find a tutorial for NEC and read the whole thing,
but it didn't help much. I guess I'm not great with the scientific
stuff.

NEC takes some getting used to, and, the tutorials that come with it are
aimed at computational electromagnetics folks, who already understand
how NEC works under the hood, and are really looking at "how do I put my
problem into a form for THIS particular code".

There's some pretty common "tricks of the trade" used with NEC, like
using a network to create a current source (4nec2 does this for you
automatically).

Mostly, though, it's just slogging through it the first few months until
you get your mind wrapped around the conceptual model.

Start with something fairly simple (but non trivial).. like a multiband
dipole or a 3 element Yagi with just wires (i.e. don't start out trying
to model the U-bolts and stuff).

A dipole is nice to fool with, because you can put a wire in under it to
represent a tower, for instance, and see what effect it has on the
pattern. Likewise, you can do something like model your rain gutters or
the feedline as a single wire, and see how much current is induced in them.