[RFI] W8WWV noise
Pete Smith
n4zr at contesting.com
Tue Feb 17 07:36:57 EST 2004
At 10:36 PM 2/16/04 -0600, W0UN -- John Brosnahan wrote:
>Greg, W8WWV asked me about his noise problem and I am
>checking on some radar and sounding systems to see if anything
>is out there that might make this noise. But I also thought
>the collective wisdom of the group might have some ideas.
>
>His description of the noise is at:
>http://www.seed-solutions.com/gregordy/Amateur%20Radio/Experimentation/DXNoise.htm
>
>And he has a 30 second mpeg at:
>http://www.seed-solutions.com/gregordy/Amateur%20Radio/Experimentation/Noise75.mp3
>
>If you have any good ideas let me and/or Greg know.
>"Greg Ordy" <ordy at seed-solutions.com>
>
This may be totally off the wall, but 15 years ago I was trying to finish
my 5BDXCC and put up an 80-meter full-wave loop behind my townhouse. I was
immediately confronted by a signal that sounded much like what Greg
describes. It was discrete, only on a small band of frequencies, but with
some audible short-term changes evident. I *think* (from memory) the sound
was much like his recordings.
In my case, there were actually two bands of frequencies in the 80m band,
one ca. 3505-3515, the other at 3765-3775.
I went around my neighborhood with a portable shortwave radio, and
eventually determined that the noise was radiating from one house. The guy
was willing to be helpful, and so I walked around his house with him trying
to determine where the noise was coming from. At one point, he switched on
the lights in an upstairs bathroom, and the noise suddenly ceased. The
lights were incandescent, and there were no complex electronics anywhere,
just a 72-cent Leviton silent SPST wall switch.
To cut to the chase, I replaced the switch for him, and the noise
disappeared. A few days later, I noticed another, on a slightly different
set of frequencies. I traced that one to a 3-way switching setup in the
dining room of a townhouse across the street. Again, the homeowners let me
replace a switch, and again the noise went away. I think that switch cost
$1.15 -- again, no dimmer or anything else fancy, just a switch.
I have no idea what physical mechanism was responsible, but empirically,
that's what it was. Particularly given Greg's description of the signals
that appeared at different frequencies, from different directions, I have
to wonder if he isn't experiencing something similar.
73, Pete N4ZR
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