[RFI] Mysteriouser & mysteriouser

[MikeR]

I've got a mystery noise that's keeping me off the air, it's so persistent and 
annoying.
This noise has been almost constant for several months. My utility company has
been very diligent about finding and curing it, although without success. They
used an ultrasonic dish and a radio receiver. The dish heard nothing, the
receiver heard a little bit, but it is not directional.
The source is definitely outside the house, and positively just a few degrees 
north of west.

There is a utility pole there, 1 house and a street away. It carries electrical,
telephone and cable TV lines, and has a street light mounted on it.

Another ham who lives about 2 miles away from me, and has a bigger higher
antenna with a GaSFET amp can't hear it, so I conclude it's fairly close to me.

For the last week or so, it's been worst on 6M and is on everything down to
20 meters. Sometimes it covers 160 through 6. It's audible in the AM broadcast
band.

My rig is an ICOM Pro II, and the antenna is a 4 element SteppIR with
optional 6M elements (giving me 6 on 6) at 85 feet.

I this description, a picture of my rig, and a sound file on my website at 
http://nf4l.com/buzz/
I'd sure like some help in ID'ing what the noise is.
Thanks,
Mike NF4L