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Re: [TowerTalk] DIR-DE-DIR on a 40m yagi ?

To: towertalk@contesting.com
Subject: Re: [TowerTalk] DIR-DE-DIR on a 40m yagi ?
From: David Gilbert <ab7echo@gmail.com>
Date: Sun, 14 Nov 2021 18:36:57 -0700
List-post: <mailto:towertalk@contesting.com>


If you want to make a 3 or 2 element array be bidirectional, tune the parasitic elements to the driven frequency.  Don't make it shorter or longer.  You can run that through EZNEC if you don't believe me.

73,
Dave   AB7E



On 11/14/2021 3:16 PM, jim.thom jim.thom@telus.net wrote:
You folks   that have stepIR   3 el yagis..... I believe you can reverse
the pattern
180 degs.... by turning the DIR into a REF...and vice-versa.

Question is,  can you make  BOTH parasitic elements into  Directors ?
IE:    DIR-DE-DIR.  On paper, it should become a  2 -element,
bi-directional  yagi...with perhaps  4dbd  gain in both directions .   Does
that concept work ?

I'm  assuming equal spaced elements to begin with..and  DE mounted to the
mast...above the boom a bit.

Aside from the 180 deg reversal  feature,  for  SOME applications,  having
gain in 2 x directions at once can be of benefit.

Ok, here's a  dumb question.  What if both parasitic els are tuned as
Reflectors ?   Does it implode on itself,  or is it  still bi-diectional
with gain ?

Jim  VE7RF
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