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[TowerTalk] Horizontal loop and balun

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Subject: [TowerTalk] Horizontal loop and balun
From: (Tom Rauch)
Date: Fri, 20 Jul 2001 20:23:18 -0400
> A balun work's best when it see's a pure resistance, or nearly so.  A
> balun at the end of a piece of coax, feeding a length of balanced line
> that feeds an antenna, will almost be guaranteed to see a reactive load.

A choke balun cares less if the load is reactive, only voltage baluns 
(like the W2FMI style) are load impedance critical.
> A better idea would be to place the balun at the input of a balanced
> tuner.  If there are difficulties in bringing in the balanced line to the
> tuner, then a small section of shielded balanced line can be employed.

Placing a choke balun at the input of a tuner does nothing for 
balancing of the system, although it does reduce differential mode 
stress on the balun (which usually isn't a problem anyway if you 
use a properly constructed choke balun).

After some discussion of this in another antenna forum, Roy 
Lewallen (W7EL) did an analysis and confirmed this.

73, Tom W8JI 

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