[RFI] can a tower re-radiate RFI?

Gary Peterson kzerocx at rap.midco.net
Mon Jan 25 07:59:33 EST 2016


“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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