Hello,
I wonder if I could get some advice on an RFI problem. I live in an
apartment that is part of a large house. There is one other apartment
here too, and my neighbor there has been complaing about RFI from my HF
rig. His main complaint is that I'm coming through the speakers on his
computer. My main antenna is a Butternut HF5B 2 el mini-yagi that is
mounted up on the roof. The bottom of the antenna is roughly 15 to 20
feet above his computer, and 5 feet away horizontally.
My first question is: In the eyes of the FCC, is my antenna too close to
his apartment? I have heard some people say that the FCC expects a ham's
antenna to be at least 50 feet away from any neighbors, otherwise the
ham can be blamed for interference. Is there any truth to this? I
normally run 100 watts output, and I know that my neighbor's apartment
is within the FCC's RF saftey limits. I occasionally run 500 watts for
DX pile-ups, which is also within limits, but I only do it when the
neighbor is out. It's very possible that the FCC will be coming here to
look at the problem, so I need to know if my antenna is too close (at
100w), and if I could be held responsible for the RFI problem.
I also have dipole for 30 and 40 meters, but I only use it when the guy
is out. That antenna is roughly parellel to his 2nd floor apartment, and
about 20 feet away from it. There isn't enough room here to put up
anything better.
As for cleaning up the RFI, I have not been able to do much since my
neighbor is not very cooperative. The problem is from HF fundamental
frequencies. I'm coming through the speakers on his computer, which he
insists on leaving on 24 hours a day. He won't turn off his amplified
speakers - not even before going to bed at night. He uses rabbit ears
for a TV antenna, and we are in a fringe reception area. His TV is at
least 30 feet from my antenna, and I clobber every channel. He also says
I come in through the phone line.
Since his main complaint is with the computer speakers, that is where I
have been trying to help him so far. I don't seem to cause any
interference at all on his monitor. I tried using ferrite beads on
various speaker cables and mananged to reduce the interfence by maybe
50%, but it is still very noticeable. I only had 2 beads, so I couldn't
do as much as I wanted, but I doubt that beads alone would have done the
job. He has a total of 5 speakers, with 2 separate ampifiers. At one
point I grabbed a hand-full of the speaker wires and the interferece
dropped WAY down. I'm thinking I might be able to wrap several turns of
wire around these cables, then ground the wire to simulate the same
thing. Does that make any sense? His computer is grounded btw. I
grounded it because the AC wiring in this place is not grounded.
For the phone line, I will try a bead or a torroid core. For the TV,
I'll try a high-pass filter, but I have doubts that it will help much.
It's been hard to do much of anything because the neighbor isn't very
cooperative. We agreed yesterday to work on the problem at noon today,
before he would go to work at 2 pm. He wouldn't answer his door or his
phone when I tried to reach him several times between 12 and 1:30.
Finally, just before he had to leave for work, he anwered his door. He
said he "must have been sleeping" earlier. This is typical for this this
guy, - it's happened before. So, I'm about ready to just go ahead and
operate and let him make complaints to the FCC. It's easier than dealing
with his lousy attitude. I need to know first though if my antenna is
too close to him. I'll probably be able to get in his place one last
time to try a few things though, so any advice on solving the RFI
problems is also appeciated. I've never had problems with RFI before, so
all of this is new to me.
Thanks,
Gerry KA2MGE
--
FAQ on WWW: http://www.contesting.com/FAQ/rfi
Submissions: rfi@contesting.com
Administrative requests: rfi-REQUEST@contesting.com
Questions: owner-rfi@contesting.com
|