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[TowerTalk] One off balun question

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Subject: [TowerTalk] One off balun question
From: "Jim Thomson" <jim.thom@telus.net>
Date: Thu, 30 Oct 2014 00:32:46 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
After looking at both Steve Hunt and Jim Browns material in depth, I have a 
general question. 
In regard to the many various 1:1 choke baluns on both their sites, has anybody 
actually measured
the uh between the input..and the output ??     IE: center conductor to center 
conductor.... or braid
to braid. Like using a LCR meter at low freqs.      This is more out of 
curiosity than anything.  
I measured the uh on my type 43 bead balun, 17 inchs long, using the 1 inch od 
beads slid over
RG-393 coax, and it measured aprx 38 uh. The 24 inch long version of the same 
balun measured
aprx  57 uh.  Uh appears to be proportional to length.   I also measured a 17 
inch long bead balun, but
using the old type 77 material, and it was 63 uh.   Just for fun,  I also 
measured my torroid balun...
which consist of 4 turns of RG-393 wrapped around 4 x 2.4 inch OD, type 31 
cores.... 126 uh. 

If 4 turns of 393 (.390 inch od teflon coax)  on 4  x 2.4 inch od cores is 126 
uh, then some of the designs
I see on both steve and Jims site must have huge amount of measured uh.   IE: 
5-14 turns on 5++  cores. 
BTW, I used my B+K 875-B LCR meter to measure uh.  It does the reading at 1 
khz. 

Tnx.... Jim   VE7RF
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