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Re: [TowerTalk] Fw: eznec

To: Jim Miller <JimMiller@STL-OnLine.Net>
Subject: Re: [TowerTalk] Fw: eznec
From: GM3SEK <gm3sek@ifwtech.co.uk>
Reply-to: gm3sek@ifwtech.co.uk
Date: Thu, 19 Jan 2006 14:36:24 +0000
List-post: <mailto:towertalk@contesting.com>
Jim Miller wrote:

> 
> Is there a reflector for eznec?
> 

> I am new at eznec and when I try to model a fan dipole, I get "mult
> jctn", Multiple junction?
> 
> What is the "trick" to fixing this?
> 
> Tnx es 73, de Jim KG0KP 
> _______________________________________________
> 
> On the "Source", sorry.
> 
> Jim

Don't worry - you just happen to have chosen a slightly tricky antenna 
for your first outing.

Roy Lewallen hangs out on the rec.radio.antenna newsgroup, and he also 
responds to direct e-mails... but he very reasonably asks that you read 
the EZNEC Help first.

In EZNEC, go to Help, Contents, click the Search tab and then type in: 
multiple junction. This brings up lots of references, and the first 
topic "About Sources" is the one you need.

The error message is because NEC doesn't allow you to place a source at 
a wire junction. The fix is to insert a short 1-segment wire between the 
two opposite halves of your fan dipole, and place your source at the 
mid-point.

A fan dipole may also cause a second problem for NEC, about wires 
joining from acute angles. The Help for that one ("Acute Angles") is a 
little way down the topic list that you just opened. To check whether 
NEC has a problem with your particular fan geometry, switch on the 
automatic segment tapering (in the Wires window, bottom of the Wires 
menu) and see if it makes a significant difference.



73 from
Ian GM3SEK

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