After 9 months of phone calls and complaints, PG&E finally came out
this week and "fixed" the two power poles that were causing most of my
powerline noise problems. I say "fixed" because it is too early to
tell if their "fixes" actually worked since the noise is most
prominent in the dry, hot summer. The pole hardware is nice and shiny
though :-) After they left I started listening for powerline noise
and there is still at least one noise source in the direction of one
of the poles, but I don't think it is that pole. The RFI I hear now
has some very strange characteristics. I'm wondering if anyone can
explain them. Here goes....
The RFI I hear now can only be heard on 10 meters: nothing on 12
meters, 15 meters, 20 meters, etc. A fellow ham who lives about 200
yards away from me hears it too. In fact, he's the one that told ME
about it. The RFI sounds just like broadband powerline noise and my
noise blanker can eliminate it (the NB2 button on my FT-1000MP). I
start to hear the RFI at about S1 way down around 26.000 MHz or so.
The signal strength climbs slowly as I tune up the band. NOTE - I
have a SteppIR so I am retuning the antenna as I move up so it is
resonant at the freq. I'm listening to (or close to it). The signal
strength peaks anywhere from about 28.100 to 28.230MHz, but this is
where it gets weird. Right after the signal peak it just drops off a
cliff. It's like there is a steep low-pass filter at 28.230Mhz. The
signal will be S9 at 28.230 and S0 at 28.240. It just drops off.
There is no RFI up in the phone band. There are a couple of other
strange characteristics. First, the "drop off point" moves around.
The first time I heard this RFI it dropped off around 28.230MHz. The
next day the drop off was around 28.120. Today it is around
28.210MHz. Even while listening it slowly moves around by maybe 2 or
3 Khz every second. It just wanders around a bit. The other strange
characteristic is that all of the RFI just stops completely every so
often and then comes back on a second or more later. The off time
varies as well. It seems random.
I really don't think this is from that pole. I suspect some piece of
consumer electronics or other equipment a few doors down from me.
I'll be going out this weekend with my FT-817 and 440MHz yagi to
verify that the pole is really quiet and to try to identify the other
noise source. Maybe someone has some theories that may help me track
down the newly identified noise source more quickly?
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