On 10/14/22 10:21 AM, F1AMM wrote:
I only start to know EZNEC well. If you install EZNEC, it files the manual (in English) in the form of a Word file. It is huge because the author explains a lot about good and bad modeling as well as ways to identify bad modeling. It is this notice that I translated into French and completed.
As far as I know NEC motors, other than EZNEC built-in NEC-2D, are unaffordable for an OM (QSJ).
NEC2 is free, as is 4nec2, as is MMANA.
NEC4 (or NEC5) require a one time license fee to Lawrence Livermore.
Yes, one of the huge advantages of EZNEC is the modeling assistance in the manual, which is actually generally applicable to all method of moments codes (e.g. NEC).
Antenna modeling is one of those idiosyncratic things that you learn by doing, especially the subtle points and tricks.
For instance, gridding for solids (or boxes) is a whole art in itself.
Attached are a couple of screen shots from 4nec2, for a model built with some custom built software. In one, I'm gridding a 6U cubesat that has 4 2.5m long booms. In the other, I'm gridding the ground plane under an antenna for an array radio telescope.
To keep this remotely NanoVNA related, one test of the gridding is whether the modeled feedpoint Z matches the measured feedpoint Z, and that's a lot easier with a NanoVNA. It's small enough to put inside a mockup satellite, so you don't have to worry about cables.
