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[TowerTalk] NEC-2/NEC-4 limitations

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Subject: [TowerTalk] NEC-2/NEC-4 limitations
From: cebik@utkux.utcc.utk.edu (L. B. Cebik)
Date: Fri, 11 Apr 1997 09:17:43 -0400 (EDT)
THose who have been on the list a while will remember that I expressed a
question mark in my notes on the Tee match:  were the results correct or
were they an artifact of modeling--in other words, did NEC-4 have some
unadvertised limitations?

The answer is yes--NEC-4 has some limits.  Too long for posting, I have
placed my notes on both stepped diameter limitations and on unequal
diameter wires in parallel and right-angle configurations at my site.  I
have also withdrawn the notes on the Tee match pending some alternative
modeling exercises in MININEC and MININEC PRO.

The bottom line is this:  NEC-4 is off base (and NEC-2 is in another ball
park altogether) when you closely parallel wires of different diameters
(as in a folded dipole for transformation ratios other than 4:1) and when
you join wires of unequal diameter at right or sharper angles.  MININEC,
with due caution, takes these situations in stride.

-73-

LB, W4RNL


L. B. Cebik, W4RNL         /\  /\     *   /  /    /    (Off)(423) 974-7215
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