Al,
DSL uses a number of frequency bands up to 3-4 Mhz. I (good) telephone
cable pair is 600 ohms balanced and SHOULD not radiate. The DSL at my
QTH has no detectable RFI on any frequency.
I would be looking for things such as "touch lamps", "wireless" LAN
units or any number of other consumer devices. You mention that you
shut off the main breaker at your house. Try doing the same at your
neighbors house (maybe when you know they are not home)!
Good Luck,
Bill - K6WLM
wb5jnc@juno.com 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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