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Re: [TowerTalk] Optibeam Log Yagi

To: "towertalk@contesting.com" <towertalk@contesting.com>
Subject: Re: [TowerTalk] Optibeam Log Yagi
From: Paul Christensen <pbc.law@outlook.com>
Date: Tue, 30 Dec 2025 17:57:26 +0000
List-post: <mailto:towertalk@contesting.com>
>"I would recommend that you take a look at the Tennadyne t-12, made here in 
>USA and great support. I have had mine up for for over Ten Years and it has 
>held up against New England weather no problem. It is a performer..."

Keep in mind that on any given band, the T12's gain is roughly equal to a 
two-element Yagi on a very short boom.  Boom length is what supplies Yagi gain. 
 When modeling the T12 in 4Nec2 or EZNec, you'll see that only 2-3 elements are 
active.  Of the 2-3 elements, only two will appear as primarily active.  As 
frequency moves, a different set of elements on the boom becomes active.  
Elements active at the upper frequency extreme are no longer active at the 
lower extreme.  This is clearly seen in the modeling.  Most of the LPDA 
elements serve no useful gain purpose on any given band.

For the T12 to achieve the advertised gain figures (as of when I last checked), 
you would need a boom at least 10x the current length. To get an idea of the 
boom length needed, use W8IO's LPCAD software to get some surprising results.  
I owned a T14 10-30HD between 2015-2016 and was less than impressed with it. 

Paul, W9AC  






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