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Re: [TowerTalk] stacking logs

To: towertalk@contesting.com
Subject: Re: [TowerTalk] stacking logs
From: jim Jarvis <jimjarvis@optonline.net>
Reply-to: "Tower and HF antenna construction topics." <towertalk@contesting.com>
Date: Sun, 24 Jan 2010 15:31:43 -0500
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Sorry for extending this, but another thought came up.

(Doug...aren't you glad you got this one started??)

(Gene... the tilted log post was mine, at first... )

So here's the thought, with respect to tilted logs:

The full length of the log isn't really active at any given frequency.
Only a short portion of the boom, and maybe 2 or 3 elements have real
current in them.   Therefore, is the tilt of the boom all that appreciable, in 
terms
of takeoff angle?

A tangible example:    With a 16' boom log   (is the t8 16 or 18', I've 
forgotten?   no matter.)
...  the booms would need to slope at 30 degrees.   If the last 2 elements were 
primary in forming
the pattern at 14 MHz,  and they were around 4' apart.....  the slope would 
result in the forward elements
being only 2' lower (or higher, depending on if top or bottom log) than the 
rear element.    

Is this really significant in the takeoff angle?     Intuitively, it wouldn't 
seem to be the same thing as
a yagi with the director 16' in front of the reflector.    

What am I missing?

N2EA   



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