Roy Lewallen wrote in
:

....
as a helix. There are some caveats as there always are with any
modeling process, particularly:
....

Roy,

Aren't limitations on segment size an issue, especially with small diameter
coils?

Can NEC model a typical HF helically loaded mobile whip reasonably, sy 16mm
diameter, 1.2m long with variable pitch progressing to close spaced turns
on the top 30% or so?

I suspect NEC is not a magic bullet either.

Owen