Over the years I have been involved in curing things causing QRM -mostly public
utilities. Advice: if you locacte the problem emphisise the terrible noise in
things like radios tvs and phones.. Don't talk about ham gear unless absoutly
necessary. I have given you advice -from experience. Ham problems seem to
complicate solutions. I still remember having to get a Motarola Tech (a WA5)
to photogragh graphs from a $30k spectrem analyzer. And send with a formal
complaint to The FCC; because a cable co.refused to fix a leaky transponder
that kept keying a local repeater. To make matters worse two meter traffic was
broadcast all over HBO! The power co was rough too but when the bad and
leaky transformer was killing my receiver on HF. I complained that it "tore
up" my tv reception and a crew with leak detectors was out within 48 hours.
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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