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[RFI] can a tower re-radiate RFI?

To: <rfi@contesting.com>
Subject: [RFI] can a tower re-radiate RFI?
From: "Gary Peterson" <kzerocx@rap.midco.net>
Date: Mon, 25 Jan 2016 05:59:33 -0700
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
“I?m not certain the AC in my house is up to specs.......I have a couple of 
branch circuits constantly blowing incandescent bulbs, not sure why, last year 
our prelit Christmas tree (on one of those circuits) blew every bulb, one 
string at a time....WW3S"

It sounds like you have a missing, or poor, neutral connection.  If you measure 
the problem branch circuits, is the voltage high?

I was also about to suggest disconnecting EVERY conductor to the tower to see 
if the RFI abates.  You may have something connected from the house to the 
tower that is energized all the time, such as neutral current, mentioned in the 
previous sentence, flowing on a coax shield.

A tower will re-radiate RFI.  Years ago, a friend had terrible broadcast band 
mixes all over 160 and 80 meters.  I DFed the mixes with a broadcast field 
intensity meter...a Potomac Instruments FIM-41.  Everything was coming from my 
friend’s tower.  It turns out that he had an old run of Heliax going up to a 
remote coax switch about 50 feet above ground level.  The Heliax was 
unjacketed.  The poor contact between the tarnished copper outer conductor 
wrap-locked to the galvanized zinc coating on the Rohn 25 was behaving like a 
large number of detector diodes.  Once the Heliax was replaced with jacketed 
cable, the mixes were gone.

Gary
k - zero - cx
Rapid City, SD  
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