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Noise location question

Mar 28th 2016, 14:00


Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
I’ve had some experience with locating powerline noises over the years, but I'm a bit puzzled by a recent one. I noticed broadband noise of a few S units from 160 m through 10m.

I first noticed it on 12m when I pointed my beam to the northeast. I have an MFJ-856 noise locator, which is a portable 3-element yagi with an attached receiver for the aircraft band around 135 MHz. It has a strength meter and headphones can be plugged in. Standing not far from my tower, I found that I could hear noise weakly on this noise locator, and the noise peaked in exactly the same direction as my larger tower-mounted beam.

I drove to various locations and used the small yagi to get fixes on the noise source. On a map, the headings converged around some stores on a busy highway about three-quarters of a mile from my home. Around power lines in front of the stores, the meter on my noise locator was about pegged. I also took with me a Tecsun PL-660 portable receiver. It does not hear the noise at my house on 12m, but it has only short whip antenna. When I tuned to 12m near these power poles where the noise was so loud on my small yagi with aircraft band receiver, I expected the 12m noise to be loud because I was so close to the noise source, but I didn't hear noise.

Now I wonder if the noise I located at power poles near the highway have anything to do with the 160m - 10m noise causing me problems at my home station when working weak signals. It could be a coincidence that the tower-mounted beam headings for the 12m noise and the beam heading on the aircraft band beam happened to be the same. Do you see any other possibilities?

Mar 28th 2016, 16:15


Super Moderator

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0

It is quite common for there to be multiple noise sources.

Zack Lau W1VT
ARRL Senior Lab Engineer

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