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Power Line noise - cold temperatures

Jan 17th, 16:23

n4ij

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Has anyone else had high level power line noise when the weather gets cold? I have power line noise from this direction to the ESE of my house. I have a 3 element 20m beam that can peak the noise within 5-10 degrees. The noise is intermittent at mid (maybe 40 degrees to 50 degrees temp) and as the temps decrease the becomes solid s8 to S9 level. At night, when the temps dip it makes that direction useless. I had a similar problem fixed a couple of yrs ago and they replaced a number of insulators. I don't know how they isolated the noise. The noise was being conducted up and down the line so I could not direction find it in my car. I don't know what an insulator would do to change in cold temps. My theory is that the power lines contract and cause this - maybe pulling on a connection. Of course the power company showed up at my house today and I showed the noise by rotating the antenna but the noise was only moderate (50 degree temperature. So, power lines contracting ???

Doug W5FN
Feb 7th, 17:36

WR4T

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
During the recent cold snap in the Midwest I observed and increase in power-line RFI. I have no power line noise 80% of the time, it is very intermittent or non-existent on a typical day. When the temperatures dipped into the single digits noise was S9 on 40 and S7 on 20 and constant. It mostly disappeared when temperatures went above 20 F. My theory is it is related to the load on the lines, many homes on heat pumps switch to resistance heating below 20F and energy consumption soars. I believe I have observed similar issues on extremely hot summer days (>90F) as well. The noise is too intermittent for the utility to troubleshoot, disappearing for weeks at a time.

T.R. WR4T
Mar 9th, 21:28

n4ij

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
OK today the temp was nearly 60F and the noise is horrible, Windy too as OKLA is often. I built a power line dish direction finder, but hsave not been able to identify a particular insulator or connector or even a particular pole making the noise I live in a electric COOP service and te utility is not very proficient in handling this, and at one time tey referred it to the next COOP, They were able to identify the general area,but the noise was not coing from their lines so the problem is still there. The only saving grace is that my FTDX5000 blanker works very well to a point. DXing is a thing of the past for the time being. Doug W5FN
Mar 11th, 14:22

W1VT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
The ultrasonic dish is too narrow to identify particular pole. A 400MHz Yagi and AM receiver is typically used to locate the pole. The dish is then used to locate the hardware on the pole. Some VHF handhelds have wideband AM receivers that can be used for direction finding, while others are FM only and not really useful.

Zak W1VT
ARRL Senior Lab Engineer

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