[TenTec] Balun Isolator

[Gary Hoffman]

The Term Balun refers to a matching device that connects between BALanced
and UNbalanced systems - hence the name.  A balanced load would be your
dipole for instance (in an ideal world of course).  An unbalanced line would
be your coax.  The coax provides three paths  (not two) for current, i.e.
the center conductor, the inside of the shield, and the outside of the
shield.  Current from the antenna to the rig, for example, will travel on
all three paths if nothing else is done, and thus divide unevenly in an
unwanted manner.

However, if you put a so-called current balun out by the antenna (as one of
the possible locations for it) then the current is Choked off of the outer
part of the shield (hence the term choke balun) and must therefore travel on
the two remaining paths.  Thus the balance of the dipole is preserved.

This is the deal in a nutshell.

I suggest reading Cebik's works on these subjects for a truly authoritative
treatment of the subject.

73 de Gary, AA2IZ


----- Original Message ----- 
From: "Jim WA9YSD" <wa9ysd at yahoo.com>
To: <tentec at contesting.com>
Sent: Wednesday, May 07, 2008 7:25 AM
Subject: [TenTec] Balun Isolator


> Hi alll
>
> Another confusion.
>
> An isolator or to obtain isolation or high inductance on the out side of
the coax  feed line  is to wrap 6 to 8 turns around a plastic 5 lbs coffee
can.  Some people call this an balun or current balun. Why?  This use of the
term balun to me seams to be a miss application.  What should the term
really be?
>
>  Keep The Faith, Jim K9TF/WA9YSD
>
>
>
>
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