[RFI] Line Noise Spectragraph

Paul Christensen w9ac at arrl.net
Wed Nov 19 14:53:52 EST 2008

Once again, I am at my wits-end.  Just when I got the utility company to 
clean up a four-year noise issue, I now have this.  Please see the linked 
spectrograph below.

Beginning down around the BCB, I have the following noise pattern every ~ 56 
kHz.  The linked photo is centered on 3601 kHz but it extends well above and 
below that.  Span of the graph is 190 kHz.

The frequencies of this noise pattern do not  change.  Tomorrow or a week 
from now, the pattern will look the same and the frequencies will be the 
same -- so I would rule out a random power company arc of some sort where 
the frequency and broadness changes.

In AM mode, I hear what sounds very much like an SCR buzz with no apparent 
sign of modulation.  It's always there (i.e., not something a neighbor is 
turning on/off)  Does this look like an electric fence?  Plasma TV, fish 
tank aerator?

It is not coming from my home.  I pulled the main 200A breaker and fed my 
transceiver by battery power.  All home alarm battery systems were 
completely shut down and removed from their power source.

I will soon use a small SWBC receiver to try and hunt for this but after 
four years of dealing with the other noise issue, I'm getting sick and tired 
of feeling guilty when the neighbors want to know why I'm running all over 
the place in our gated community.

Any help as to the pattern would be greatly appreciated and I mean greatly.

Paul, W9AC


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