Sal M. Onella wrote:
"Rick" wrote in message
...
I have been wrestling with power line noise here for almost a year.
Power company hasn't been very successful in locating it so I started a
coordinated search.


My local utility has one tech who does power line noise investigations and
I'm happy that he solved my problem. He identified three "problem poles"
and a week later, the noise was gone.

I can't answer your question about how far power line noise will travel but,
since you've put so much effort into this already, this next may be worth
doing, too.

One of the tech's tools was an audio detector, which he aimed toward the
tops of all the poles on my block. It was a 16-inch clear parabolic
reflector with a microphone mounted at the focal point and an amplifier
feeding headphones and a meter. The tech was listening for the sound of the
offending arc. Never mind the RF -- find the faint sizzling noise by ear!!

You got it.

For a small fortune, these guys will sell you one: http://www.paradish.com/

You could definitely make one. This article
http://www.solorb.com/elect/misc/bige/ illustrates the idea (from a Google
search of "big ear" microphone) and it looks like he used an old wok.
(Are woks parabolic.)

The old style cheap woks are parabolic. The newer ones which have a flat
bottom are not. I have a 24 inch Al parabolic dish. It isn't very
stealthy, but it's lighter and bigger than the woks.

There are some nice features about hunting down RFI problems with sound.
That parabolic reflector can be aimed right at the pole, and in
combination with the short wavelength esp at ultrasonic frequencies will
let you zoom in on the problem pretty quickly. Trying to close up DF
with HF is like trying to change directions on a cruise ship.

So, if you want to impress the power company ...

If you are doing it near your own house, DO check in with the neighbors
telling them that you are locating the source of noise, and it might
eliminate any interference they might be getting now.

- 73 de Mike N3LI -