Jim, I've not experienced that problem when the model is properly set up.
I've designed and constructed many antennas from HF through L-band and the
1.42 GHz deep space neutral hydrogen emission using 4NEC2 which uses the
basic NEC2 engine. All have worked fine for me when finally implemented.
However, all the NEC engines have trouble handling "ground". Once the feed
impedance of a modeled antenna is determined with the NEC engines (EZNEC or
4NEC2 and some others), I then transition to SimSmith for the matching
solution.
Dave - W?LEV
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On Fri, Oct 14, 2022 at 5:56 PM Jim Lux <jimlux@...> wrote:
On 10/14/22 10:28 AM, Michael Black via groups.io wrote:
Be aware that EZNec with the built-in NEC engine doesn't work well on
higher frequencies like 50MHz. The resonant point is off by a couple
hundred kilohertz. The latest LLNL engine gets it right.
Can you provide more information? NEC *defaults* to 300 MHz (1 meter
lambda), it's basically just geometry. I've done a *lot* of NEC
modeling and never seen errors like that.
I *have* seen errors due to unwise segmentation, and with single
precision, and situations where the assumption of uniform current
distribution on the surface of a wire is broken. But that's not
frequency related.
Mike W9MDB
On Friday, October 14, 2022 at 12:22:13 PM CDT, F1AMM <
18471@...> 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).
--
*Dave - W?LEV*
*Just Let Darwin Work*
--
Dave - W?LEV
