For a basic yagi, multiband or otherwise, NEC2 works fine. Where NEC4
provides an advantage is with unusual geometries and features in the ground.
73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie
-----Original Message-----
From: Tom Hellem
Sent: Friday, December 01, 2017 6:45 PM
To: Jim Thomson
Cc: towertalk@contesting.com
Subject: Re: [TowerTalk] 2-el 15/20 meter duobander
Jim-
I am curious about why you are suggesting that one needs NEC 4 software to
design a 2 el. duobander.
FWIW I basically took a C-3 and removed the 10M elements, tweaked it with a
model in EZnec (NEC 2), built it according to the model. It ended up being
resonant exactly where the model predicted with an swr of 1.0 at resonance
on 20. However on 15 it ended up with 2.0-1 swr . Maybe I should have used
NEC4.
Tom H
KOSN
On Nov 29, 2017, at 6:04 AM, Jim Thomson <jim.thom@telus.net> wrote:
Date: Tue, 28 Nov 2017 16:38:40 -0700
From: W0MU Mike Fatchett <w0mu@w0mu.com>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] 2-el 15/20 meter duobander
<Why not take the measurements from a C3?? I think it is just 2 ele on 20
<and 15 with 4 on 10.
## wont work. Different yagi, and even if it did sorta work, he would
have to use the
identical tubing schedule. Whats required is auto ez, NEC-4 and yagi
mechanical to
design the eles.
Jim VE7RF
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