Al,
You need to get serious about ferrite chokes being installed everywhere, and
not just one choke, multiple.
It is imperative to suppress all of the common mode currents brought about
by various imbalances and ground loops. Anywhere RF can enter into the alarm
system ADT alarm as well as having ferrite toroids and snap on chokes on all
of the source RF carriers such as audio leads (mics, headsets, audio in /
audio outs from computers, power cable, as well as having choke baluns for
common mode suppression on all RF coax cables and feedlines.
Don't get me wrong, this is a lot of work, but necessary, with some
installations. Many hams don't have proper effective ground systems of their
equipment and they create higher impedance paths to ground and/or ground
loops due to the lack of effective grounding designs or having longer than
recommended ground conductors going to poor ground points to begin with.
You also need the proper ferrite materials for the types of RF suppression
you are dealing with in order to achieve the high impedances necessary to
choke out the common mode currents from getting into your telephones,
computers, stereos, TVs, etc;
If the problem is severe enough, you could even see other effects like
"Touch Lamps" coming on when you transmit.
A funny story, when I was stationed in North Carolina, back in the late
1980s, I was operating a contest one night late, and without knowing it,
when I modulated, the neighbors touch lamp would come on in their living
room, and flicker.
Well evidently the couple that was sleeping woke up, and the wife grabbed a
baseball bat, since she thought that there was an intruder in the house
downstairs.
Well she went down stairs with the baseball bat in the total darkness,
except for the Touch Lamp flickering on and off, and when she crept up on
the lamp with her baseball bat, her husband came around the other side
entrance to the living room, and the wife took a swing and almost clobbered
her own husband.
It took a while, a few nights to realize that I was the culprit with "Living
Room Touch Lamp RFI".
This really happened, and we laugh our butts off every time we think back on
the home defense strategy.
Thanks,
Jim
K4PV
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]On
Behalf Of W4ABW@aol.com
Sent: Sunday, April 22, 2007 12:01 PM
To: geraldj@storm.weather.net; tentec@contesting.com
Subject: Re: [TenTec] RF gets into computer (ADT Alarm System)
I use the FT-1000MP and I get RF (I think) into the ADT Security alarm
system. It sets off the alarm when its not armed. Any thought on this? Its
only
troublesome on 40m where I use a dipole that's closer to the house than my
80m
dipole and my tri-band beam. My 80m dipole is just a lil farther away and
has never caused this effect. The firemen have been out here twice now.
thanks
Al
W4ABW
Raleigh
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