[TowerTalk] Best Balun

[Jim Thomson]

Date: Wed, 26 Nov 2014 18:26:09 -0800
From: Jim Lux <jimlux at earthlink.net>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Best Balun

On 11/26/14, 5:20 PM, Jim Brown wrote:
> On Wed,11/26/2014 5:02 PM, Herbert Schoenbohm wrote:
>> (Chip K7JA) their bead balun model EB-1 as this is easier for me to
>> install on the boom compared to the Comtek boxed unit which also
>> looked very good with their specs..



>
> AAARGH! Most strings of beads are terrible chokes, because they are
> inductive, not resistive, at the operating frequencies. This is
> discussed in the tutorial I referenced earlier in this thread.

they use a Amidon 73 mix for this particular balun

I wonder why they don't use a 31 mix? tradition?

##  They rate the eb-1 at 1.5 kw ccs..and 2.5 kw pep.  It uses 50 x type 73 beads over 303 teflon coax.
http://www.force12inc.com/products/eb-1-1-8-to-30-mhz-high-power-1-1-ferrite-bead-balun.html

##  They did not use type 31 beads for a reason.   It would overheat and blow its brains out if 31 mix was used. 
The Z just is not high enough to use type 31.  

##  Ok, if you want some real heavy duty baluns,,, with a choice of either 50 or 75 ohm coax.... and anything from
50 ohms on the output side up to 600 ohms... for you folks with  200 ohm yagis, etc.  http://www.smc-comms.com/hf10_transformer.php
Good for 1 kw average, 4 kw pep.   Weighs 5 kg. 

##http://www.smc-comms.com/hf100_transformer.php  Now this baby is good for 10 kw ccs  / 40 kw pep
50 or 75 ohms in....and ur choice of  50-75-100-200-300-370-450-600 ohms.   Weighs 60 kg. 

##  http://www.smc-comms.com/hf300_transformer.php   30 kw version, 120 kg....note all these baluns cover 1.5-32 mhz. 

##http://www.smc-comms.com/hf500_hf1000_high_power_matching_transformer.php  Alas, these pair of baluns only cover
3-32 mhz.  rated for 50  or 100 kw CCS AM.   Your choice of 200 or 300 ohm balanced outputs.   At 450 kg, they are slightly
heavier than the KT-34XA, and will probably overload your tower as well.  3.125 inch connectors don’t come cheap either...
for the small balun.   The bigger one uses the 6.125 inch connector.  Note, they mention these two don’t have ferrite in em at all. 

##  There are several maker’s of high power commercial baluns.  It would be interesting to see how they are constructed.

Jim  VE7RF