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[TowerTalk] iteraction between 220V line and feedlines

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Subject: [TowerTalk] iteraction between 220V line and feedlines
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Date: Fri, 26 Nov 1999 13:26:33 EST

<< (Scott Ginsburg),

   Open wire line doesn't radiate if the currents are balanced and I've run 
it fairly close to power lines of 1-2' when necessary and other wires without 
a problem.  Coax with RF spill over on the shield got into everything 
regardless of distance.  If a ground cable to the ground rod is 1/4 WL long 
it will present or be a Hi-Z at the connection and do nothing.  It's always a 
DC Ground.
     Adding the toroid donuts to the power lines should help cool them from 
stray RF from the antenna. Palomar has a meter to measure RF on power wires 
or coaxes.
called the RF Current Meter PCM-1.  Since I use techniques that prevent RF 
Spill over now I never measure any RF on my coaxes in the shack anymore.  
Power lines in conduit is a good idea all the time.
     If your matching system permits balance adjustments, there is a simple 
test of true balanced feed.  For example with a T or Gamma Match (Gamma is 
the last resort) match using the MFJ SWR Analyzer, place your had on the 
center of the DE, coax shield or mast and see if it upsets the SWR.  If it 
does adjust ends until no change of SWR occurs (1:1 properly adjusted for 
SWR).  If your system still has spill over the Toroids at the feedpoint are 
RF resistors and will dissipate it (2nd choice).  The coiled coax doesn't 
work in the high current section.  It works 1/4 WL lower at the Hi-Z or E 
point.  If you use open wire line I suggest RF Ammeters to check balance of 
the currents. 

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