On Sat, 11 Jul 2009 21:56:47 -0700, Noskosteve wrote:

This is a long thread and I hope I read enough and am not repeating.

I've been involved in a power line noise problems here in McHenry
Illinois for the last year and can make a few comments.

McHenry? I lived there from 1948 to 1955 in the McCollum lake area.
Corn fields everywhere. When I went back in 1993 the old neighborhood was
still there but the cornfields had turned into condo-fields.
I would have hoped the new construction would have put the new wiring
underground so you would not have a problem.
Are things still on poles?

There are some very good references on the ARRL Web site. I've read
them, one of the books and consulted with Gene Preston, K5GP a pro and
one of the paper's authors. They should be top on your list of things to
read.

Main page:
http://www.arrl.org/tis/info/rfi-elec.html

This is good, but long:
http://www.arrl.org/tis/info/rfi-elec.html

A good summary:
http://www.ctdxcc.org/powerlines/

Some others:
http://www.arrl.org/tis/info/pdf/0112068.pdf
http://www.egpreston.com/RFItalk.ppt

There's lots more on-line, but these will make you an expert quickly.
(:-)...

Power line noise is almost always quite broadband. It won't just be on
one band. Therefore, it is best to hunt on the highest frequency
available that hears the noise. The noise travels further at lower
frequencies and pinpointing a source is more difficult. Three pros I
have talked to say this. The author of one of the books uses a modified
TV antenna to get up to 900 MHz and above. An Engineer at the
equipment manufacturer, Radar Engineers, says the same thing :
hhtp//:www.radarengineers.com

They make an ultrasonic ear, a 330 MHz beam/Rx, and a wide range
receiver/spec analyzer for power line noise hunting. The local power co
here (ComEd) uses all these.


In addition, at higher frequencies you can get more gain in a relatively
small size and a resulting narrower beamwidth to better ID the pole. I
happen to have the same Cushcraft beam Gene Preston uses (shown in his
paper below) and it works nicely to pinpoint a pole or when further
away, a region of radiation.

My measurements show the same thing. The noise is at a lower level at
higher frequencies, so some gain may be in order. I also use preamps at
times.

I have access to the very same ultrasonic and 330 MHz.equipment. I also
have a 2M beam, 450 beam, 700 beam and 1296 beam, spec analyzer, yadda,
yadda....

We're pretty heavy into this and getting impatient with ComEd.

The ultrasonic will ONLY hear arcing that is in the air OUTSIDE things.
Our arrester problem has NO ultrasonic signature (our problem appears to
be up to 100 arresters causing noise 15dB above the level when the line
is de-energized).
The ultrasonic dish can identify an individual insulator or arcing
component.
Hot clamps and ground wires, yes ground wires, can be a significant
source. Including the large staples that hold the ground wire to the
wooden pole !!

Still poles?

The comments about making sure *your* noise is fixed is right on as
well. Identifying the particular signature of the noise should also
be done. This is with an O-scope so you can see the time signature (the
wave shape) This can also help identify multiple sources.

A good O-scope can be many kilobucks. Mine was, Tektronix, but worth it.


We currently are waiting for the manufacturer to test 30 arresters that
were swapped out. These arresters are 100% tested for RF noise and I'm
worried that the test is bad.

FYI:
They also have a 22 blank cartridge in them. If the arrester fails such
that is conducts and heats up, the cartridge fires and blows the snot
out of the ground connection to free up the line.

I can just imagine a really hot day.

Good luck
73, Steve, K9DCI at arrl dot net

Bill Baka
Real mail is
My parents transplanted me to California.