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Re: Topband: Choke baluns

To: Pete Smith <n4zr@contesting.com>
Subject: Re: Topband: Choke baluns
From: "Gary Smith" <Gary@doctorgary.net>
Reply-to: Gary@doctorgary.net
Date: Fri, 21 Nov 2008 10:03:01 -0500
List-post: <topband@contesting.com">mailto:topband@contesting.com>
> > >The kits listed below have worked very well
> > >for me on my beverages:
> >
> > >http://www.antennex.com/palomar/balun_kits.htm
> >
> >These are vastly inferior to the chokes I've recommended. That is, my
> >coaxial choke designs will provide MUCH greater isolation between the
> >Beverage and the coax.
> 
> 
> You might also take a look at the two-choke design in recent editions
> of ON4UN's book (the one that has the shield grounded between two
> strings of beads about 15 feet from the matching transformer, with the
> shield at the transformer floated).  See, for example, Fig 7-88 on
> page 7-60 of the 4th edition.  I do not understand the theory, which
> is explained in the book, but W1HIS, who also has done extensive work
> on chokes for noise reduction, says it will work as advertised, making
> the most out of your choke impedances.  I use this design with a K9AY
> loop, which has a very low output level, and so is very much affected
> by shield pickup.
> 
> 73, Pete N4ZR
> 
> 73, Pete N4ZR

Excuse my ignorance but on a receiving only antenna like the K9AY, 
what is the difference I will experience between having an excellent 
choke and no choke on the K9AY feed?

At my QTH all the radials, feed lines and control cables are on 
ground so if a problem exists, it would likely happen in this 
scenerio. I am using 175' of 75 ohm cable to the K9AY.

I do find the K9AY is quite effective but perhaps there's even more 
effectiveness to be had? 

Thanks,

Gary  
KA1J
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