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[TowerTalk] 80M dipoles/height gain

To: <towertalk@contesting.com>
Subject: [TowerTalk] 80M dipoles/height gain
From: W8JI@contesting.com (Tom Rauch)
Date: Tue, 24 Jul 2001 09:45:07 -0400
Hi Tom,

Like most cases, the installation is too complex to tell what is 
causing what.

>  The Elevated GP is 75 ft North of my 55 ft tower
>  with 5L10's at 32 and 62 ft plus 4L15 at 55 ft.
>  This does seem to affect the pattern to the South
>  since I was unable to work XZ0A at sunset on the
>  GP but did work them on the wire vertical located

Even without any measurements, we know that is a situation where 
more than one "antenna" radiates significantly at any one time.

> > How traditional are your verticals?  
>  See JUNE 1994 QST for elevated GP
>  Feed impedance is 17 ohms resistive at 3.6 MHz
>  fed with parallel 1/4 WL RG59 to 150 ft of 1/2 inch
>  CATV hardline.  10 radials insulated from tower.

Of course the efficiency of that setup can be all over the place, as 
can the pattern.

With so many unknowns, there is no way to tell how much 
polarization and/or wave angle is responsible and how much 
efficiency/pattern is responsible for differences.

This is almost always why what works at times at one location is 
not repeatable at other locations. Unfortunately all we can talk 
about are ideal cases, and hope everyone can come close.


73, Tom W8JI
W8JI@contesting.com 

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