[TowerTalk] KT36 Balun

Jim Thomson jim.thom at telus.net
Mon Apr 28 11:52:29 EDT 2014

Date: Sat, 26 Apr 2014 19:43:57 -0700
From: "Jim W7RY" <w7ry at centurytel.net>
To: <towertalk at contesting.com>
Subject: [TowerTalk] KT36 Balun

Which balun do you recommend for the M2 KT36?  A voltage balun or a current balun? I run 1500 watts during RTTY contests.

I?m planning on winding my own. I have Jerry Sevick?s book on building them.

Jim W7RY

##  You need a 1:4 balun..since the ant is 200 ohms.   Use either a balun designs 1:4 balun..like a 5 kw unit,
or get one from array solutions.   Array solutions will make a 1:4  balun in any power rating you want.

##  Then  follow it up with a 1:1  choke balun, like a bead balun  made from type 43  or type 33 large diam beads 
slid over  RG-213  or  RG-393 coax.   Or use a k9yc design, optimized for  20-10m.   Or get a 1:1  choke balun
from  baluns designs. 

##  The  1st balun does the  1:4    transformation..right at the feedpoint.   The 2nd balun, 1:1  choke type...is right in front
of it.   The 2nd balun kills any residual RF.   Between the two of em, you end up with your 1: 4 transformation, plus
a sky high choking Z. 

##  IE;  50 ohm coax up the tower, then  1:1  choke balun, then  1:4 balun.  Most 1:4 baluns will do the transformation
job ok,  but  will not have the high choke Z  you are after. 

Jim  VE7RF  

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