I got a first hand lesson in the technique Burt describes from K3RFI, the ARRL
power line noise guru. He came to my QTH in response to a complaint I filed
with the FCC through ARRL and showed me the 'fingerprint' method he uses to
locate a noise source.
When a breakdown occurs causing an RF noise, the arc may spark several times
over the peak of the cycle and counting the number of spikes gives you the
fingerprint of an individual noise source.
K3RFI connected his service monitor to my HF antenna and noted the fingerprints
of several noise sources and then worked with the power company to locate the
individual noise generators.
In my case, he checked on three consecutive days and found three different sets
of noise sources. I have a 110 KV power line running overhead in the location
where I spend the summer, and it was an old line with a lot of loose hardware
problems. In my case, the consensus of opinion by K3RFI and the ARRL was that
I should move to a quieter location.
I have fought that problem for over 20 years now, with the local power company
and with the ARRL/FCC complaint route and the noise is still there. I don't
even bother to put up an HF antenna at that location any more. Noise on the 2
meter band is always pegged out on a receivers S meter. It does taper off a
lot at 440 for whatever that is worth.
73 - Jim W5ZIT
--- On Thu, 12/25/08, Burt Lang <b...@gorum.ca> wrote:
From: Burt Lang <b...@gorum.ca>
Subject: Re: [Repeater-Builder] Six Meter Repeater Noise Issues
To: Repeater-Builder@yahoogroups.com
Date: Thursday, December 25, 2008, 12:18 PM
I have found a simple way to verify if noise is coming from a power
line
arc-over. Any such noise generated by a power line will only occur as
the voltage on the line approaches peak and it will be synchronized to
120 Hz. Put an oscilloscope on the audio while feeding an unmodulated
carrier into the receiver and set the time base trigger to 60Hz. If the
noise is pulsing and stays solid on the scope display, you have power
line noise. If it is steady (not pulsed) and not synchronized to 120
Hz, the power line is not the culprit.
Burt VE2BMQ
.
