[RFI] 200 khz AC line noise

[Aaron Kreider]

The noise is highest at the electric panel in my basement (and at 
various poles), but my guess is this is because the house is a triplex 
and we have four electric panels. So far the noise seems to be related 
to the amount of wiring period.

At some point I'll turn off the house power, but I'm pretty sure it 
isn't coming from our house as I've found this noise literally ALL over 
the neighborhood. I walked a 5 block by 5 block area and there wasn't 
any pattern.

Is there a common failing in electric poles and/or transformers that 
causes them to produce a medium amount of noise at 150-250 khz (and then 
at lower levels on higher frequencies)?

Or is it probable that this noise is coming from further than 5 blocks away?

I read on powerlinenoise.com website that the guy tracked down noise 
from across the Chesapeake Bay - over 17 miles away.  So maybe my search 
radius is too small. On the other hand, there are maybe 40-50 houses per 
block -- and if I extend my search radius too far I'll just find a lot 
of noise sources that aren't bothering me.

I might try to get the noise on a higher frequency so that I can build a 
yagi and do a better job of direction finding.  Though I don't have a 
good VHF radio.  I'm getting a QS1R (which will be nice as it will give 
a spectrum view of the noise floor), and I have a cheap uniden portable 
scanner that doesn't have a signal strength meter.  Also, tentatively I 
think the noise is pretty weak on higher frequencies -- so it is hard to 
hear at 15 mhz and thus will be very hard to hear on 2 meters.

Aaron