[TowerTalk] Subject: 4:1 balun questions KT-34XA

[Earl Morse]

You can get higher power capability by using a larger core, stacking multiple cores to make a larger core, or using 2 1:1 baluns on separate cores in a series parallel combination to make a 4:1 balun.

Sevick's books cover it pretty well.  This page talks about it as well:  http://www.g8jnj.net/balunsandtuners.htm

Earl
N8SS


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Message: 6
Date: Mon, 27 Oct 2014 22:37:41 -0700
From: "Paul " <radioboy at telus.net>
To: <towertalk at contesting.com>
Subject: [TowerTalk] 4:1 balun questions KT-34XA
Message-ID: <008c01cff271$4c41a330$e4c4e990$@net>
Content-Type: text/plain;	charset="us-ascii"

Hi Guys,

Getting ready to put up my KT-34XA this weekend and just trying to get the
balun right. I have been experimenting this week with cores and windings and
have found a combo that sure looks good on the MFJ-259 and seems to not get
too hot on a soak test...what I have come up with is a core from Arnolds MPP
series which is 125u, 2" diameter and with 8 turns 14ga enamel with
Fiberglas tape spacers, bifilar wound for each half ,on one core, I am flat
from 1MHz-45MHz with the MFJ-259. Running 500W through it for 5 minutes gets
it hot, but I can still hold it. I want to end up winding it on 2 cores,
half on each and am wondering if I should use the same # of turns on each
core as I would if it were a single core, ie 8 turns on each core, then
connect to make it a 4:1, or do I need to modify the turns count when I
split to 2 cores? Also, when splitting to 2 cores, do they need to be
oriented in any particular way or can I stack them one on top of the other,
like 2 doughnuts? The antenna is all rebuilt and tested with my single core
balun....just need some + temps and no snow for the weekend.

Your advice is greatly appreciated.

73
Paul
VE7KHz 



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