Re: NEC-LIST: NEC3, NEC4 & Radius Jumps

Nec-List,

Q1: I have created a model in NEC2 where the segment radius changes
abruptly (due to periodic capacitive loads). Apparently, the accuracy
of the model can be compromised by this abrupt radius change, although
the magnitude of this error is unclear. The abrupt radius change is
needed to ensure that the loaded segment's tiny length be
significantly larger than its radius. This situation occurs in both
curved conductors and straight conductors. I have also considered
using the EK (extended kernel) card so that I could get away with
smaller segment length to radius ratios. However, this is ineffective
for curved structures.

Assuming that I do not have the luxury of gradually decreasing
adjacent segment radius to avoid abrupt changes, does anyone know
anything about how a model's accuracy is compromised by abrupt radius
changes between adjacent segments? What is 'too abrupt'?

Q2: I heard that NEC4 (or maybe NEC3) can handle abrupt radius
changes. Is there any truth to this? Where (and how) can I get a
copy of NEC3 or possibly NEC4 ??

Any information would be GREATLY appreciated. Thanks,

Jeff Keller
University of Western Ontario, Canada
Department of Electrical Engineering
Received on Fri May 09 1997 - 10:57:27 EDT