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Re: [TowerTalk] Open wire line

Subject: Re: [TowerTalk] Open wire line
From: Rob Atkinson <>
Date: Tue, 1 Dec 2009 11:25:00 -0600
List-post: <">>
Despite what some wish to believe, it is easy to put up a balanced
antenna and feed it with balanced feeder.  You only need construct a
1/2 wave dipole fed at the center and get it reasonably high and in
the clear.  let the feed hang down and rout it over ground on
insulated supports such as PVC pipe and bring it into the shack
through insulated feed-throughs or a plexiglass window pane.   Tune it
with a link coupled tuner such as the Johnson Matchbox or Don's tuner
and float the feeder side above ground as is done in the Johnson
Matchbox.  Make the feedline an odd multiple of 1/8th wavelength at
the 1/2 w. frequency of the dipole.  You will not need any baluns
anywhere with this; the feed will be balanced, and the link will stop
common mode by acting as an RF isolation transformer between the
balanced feed and the unbalanced coax.  In fact, the tuner can be
thought of as a variable balun itself.

Some seem to have had a bad personal experience with balanced
feedline.  That is a shame but it does not justify a general
condemnation of balanced feedline.

BTW, the usual method for typing superscripts and subscripts in basic
ASCII is  just the number or letter or Greek spelled out (first letter
cap if capital Greek letter) right after the variable; two asterisks
if an exponent.  for example I squared  I**2  For square or cubed
root, I**(1/2) or I**(1/3).   Subscripts are in curves.  Inductive
reactance = X(l)



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