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[TowerTalk] W2DU Style Balun

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Subject: [TowerTalk] W2DU Style Balun
From: (ABowenN4OO)
Date: Tue, 05 Feb 2002 13:37:16 -0500
How many beads of what type material are needed to construct a choke balun, 
using RG303, for a balanced antenna operating 40M-10M?

How many beads for the same thing operating from 80M-10M?

I would like to write it down in my antenna notebook so that I can 
hopefully remember how many of what type to keep on hand.

It would appear that there are some differences of opinion (or fact) on the 
proper bead composition for this application.

W2FMI in his book "Building and Using Baluns and Ununs" criticizes W2DU for 
the use of "lossy high-permeability beads (2500)..."(A permeability of 2500 
corresponds to #73 material-N4OO). W2FMI does not specify which material he 
thinks would be optimum, but infers that something "lower" would be more 
efficient. Perhaps "lower" means something of the order of #43 (850) 
material. In another chapter W2FMI suggests that something higher than #61 
(125) and 64 (250) is required to obtain the necessary choking reactance.

W8JI has posted his experiences with these devices, but I failed to write 
down the information. W1JR did not say in his recent posting what material 
he prefers.

Can someone sort this out for me?


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