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[TenTec] strange QRM/QRN/RFI source?

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Subject: [TenTec] strange QRM/QRN/RFI source?
From: kw0d@netexpress.net (Dave Kamp, KW0D)
Date: Wed May 14 23:38:11 2003
Just released today was FCC-03-105A1, the decision on several Amateur
allocation interests.  Heavily embedded within, are notes on the parry
between Power Line Carrier users and companies... PLC is the use of
power-line spans (or distribution systems) to communicate.

Som areas of the country are currently under experimentation where Power
Line Carrier systems are being used to pipe in broadband internet access.
Likewise, many home-handy devices (like X10 and other remote-control units,
remote telephone extension boxes, etc) use Power Line Carrier to extend
communications.

Hence, I suspect that your problem might be QRM of the PLC variety.

DK  :-)


At 12:47 AM 05/15/2003 GMT, you wrote:
>
>Greetings all,
>
>(First, my apologies for the length of this post, but I wanted to give as
much info as possible in the hope of tracking down whatever we are hearing.
TNX.)
>
>I'd like to enlist the aid of the "brainpower" of this group in
identifying the source of some strange QRM/QRN/RFI that has shown up in the
past few days at my QTH. It all started Monday night when my XYL asked me
what she was hearing on the AM BC band. She's a KC Royals baseball fan (the
result of having grown up on a Kansas dairy farm) and one of the Royals
stations she usually listens to is on 690 KHz. I started investigating and
we discovered that the signal was also showing up around 830-840, 970
(+/-), etc. as well. I went through the routine of checking everything in
the house -- no computers, etc. on -- and even flipped the main breaker for
a few seconds (the interference was still there). I also did some
"sniffing" with an AM portable radio and the signal seemed to be strongest
around both the electrical outlets and telephone jacks, making me think
that is how the interference is coming in (both power and phone are aerial
and obviously in close proximity).
>
>I also checked and found the signal on 160M at around 1800, 1935, 2070,
and 2215. (I say "around" because it was 6 KHz or so wide and seemed to
vary in bandwidth.) It sounds like some sort of data stream; perhaps the
best way I can think of to describe it is that it sounds similar to a slow
scan signal. I'm calculating that the fundamental is in the 138-139 KHZ
range based on the spacing of the signals.
>
>At this point I'm wondering if possibly this is a DSL system at a
neighbor's house gone haywire (as there are DSL channels in the 138-139 KHz
range), but if any of you have any better answers, I'd like to hear them.
>
>TNX/73, Al
>
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---------------------------------------------------------
73's from KW0D Dave in LeClaire, Iowa
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