[TowerTalk] current balun question

Jim Thomson jim.thom at telus.net
Tue Mar 14 23:38:48 EDT 2017


Date: Tue, 14 Mar 2017 12:10:14 -0800
From: Christopher Brown <cbrown at woods.net>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] current balun question



My solution was to take 10 1.25 long .5 id cores and slip them into 1.5"
id (before shrink) 3:1 heavy duty thick wall adhesive line shrink tube
(used for buried cable splicing in telco and power industry).

On that front, we could really use an expert opinion.

Jim, what is your take on

Type 31 2631102002 v.s. Type 43 2643102002 when around .4" coax?

###  For VHF UHF, one would think this would be the one place where beads
on  .405 od coax would be simple and very effective.   Esp the  1.020   OD x .505 ID 
x 1.125 long types. 
.
Both the Z and the resistive portion would be very high, as per the farir rite
notes for both 31 + 43.
http://www.fair-rite.com/product-category/suppression-components/round-cable-emi-suppression-cores/

##  Type 31 beads appear to have the slight edge over type 43, at least as noted between 100-250 mhz. 
175 ohms RS  at 150 mhz.   10-20 beads would provide outstanding performance. 
Like  1750 -  3062 ohms RS.  The  type 31 beads typ cost more than type 43.  So factor
that in.  

VE7RF


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