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Power LIne Question

Dec 11th 2015, 19:20


Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
I am working with the local power company to find several noise sources. One is to the SE direction from my tower and reads S-9 on the TS-690 (AM mode). What I am wondering is how far out do I need to look for the source. My tower is at 90Ft with a 5EL 10M yagi. We have focused most of our time out to 1/2 to 1 mile. Should we be looking farther for a source that is S-9. Area is semi rural, mostly flat.

When DFing, I am using a 137MHz, 3EL yagi and a HT tuned to 137MHz AM. That seems to work pretty well for 100-200 Ft. The power company rep uses an Ultrasonic detector and needs to be at the base of the pole. If anyone has done lots of this kind of work and has some past experience in appropriate distances, would appreciate some pointers.
Jan 4th 2016, 16:23


Joined: Mar 1st 2011, 09:28
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Total Posts: 0
Trying to find power line noise can get involved. I had a similar problem about 4 years ago. A ham - online, that has a web site dedicated to this type of problem, and was an engineer and ex utility lineman gave me some advice. Utility power is 60 cycles, anything other than 60 cycles will radiate over the power lines.
Suggestions were to build a loop antenna for radio direction finding. Start at the pole closest to your house. Listen to the noise level, walk away from your home, does the intensity level change?
At each pole, strike the pole - near the base, with a 10 lbs. sledge hammer, does the noise level change in intensity or momentarily go away?
This type of test is for arcing / loose hardware.
Keep walking towards the noise, eventually it will get louder until you get past the point where the noise is located, and then it will reduce in intensity.
This is just for power-line noise.
RF noise is a whole different ball game.
If the source is broadband over power-line - some type of transmitter connected to the power-line, you will need to find the transmitter and report it to it's owner and eventually the FCC if you can't get them to shut it off or make it stop making noise.
Utility companies - Water, Gas, Electric uses these types of transmitters / receivers to monitor and report your meter readings or control wells, storage tanks, and pumping stations. In my situation, this involved walking the line approximately 1 mile in both directions from my home. The discovery was a single utility pole outside of a Pennsylvania American water company pumping station that was using the power line as a antenna and had a bogus meter / transmitter - Turtle System - installed. The RF level was from 60 Hz to well over 3 GHz.
The electric company spent over one hundred thousand dollars - replacing faulty transformers, inspecting lines and insulators in the neighborhood, just to fix a problem they did not create. They even hired a outside contractor with a special helicopter and technician. The technician sat on a bolster chair and inspected the power line and insulators. The inspection also involved using a infrared camera, thermal imaging, and a video camera, used to document the condition of the power line and insulators, probably for insurance reasons. All inspections were done manually - hands on. Your noise could be as much as 5 miles away, depending upon what kind of noise it is, and what is creating the noise. It could be a grow light ballast or something else, not even related to the power company's equipment that is coupling with the power line.
I would suggest that you find other hams in the neighborhood with a similar complaint.

Borrow a different transceiver or two and see if the noise level is similar or different.

The TS 450 / 690 is not a very good performer when it comes to noise rejection.

The ARRL furnished me with the name of the gentleman that helped me with my power line noise problem complaint, and helped me resolve my issues.

ps. - A subsequent problem discovered while doing these inspections was that the transformer feeding the power to my home was faulty and was not delivering a true 120 VAC / 60 cycles. My equipment showed a funky 120 VAC that fluctuated between 50 and 100 cycles. Incandescent light bulbs failed at a rate of about once a week. The motor in my refrigerator, and power transformer for my furnace sounded like a airplane getting ready for take off at the airport. It destroyed the wall wart transformer for my Craftsman cordless drill battery charger and all the batteries in my cordless phones.
I really did do the neighborhood a big favor by complaining about the power line noise, more then they will ever know! There was 6 homes connected to that transformer! Each of them experienced some type of damage caused by that faulty transformer.
Jan 4th 2016, 19:43


Super Moderator

Joined: Apr 4th 1998, 00:00
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Total Posts: 0
If power hardware is failing (arcing) and causing RFI, it can fail in a big way if mechanically rattled. People have been killed doing this.

Start here to learn about power line noise and what to do about it, please:

You can call the Lab after reading the material provided on the link if you have any questions.
860-594-0392, Mike Gruber, W1MG is the expert.

Bob Allison
Senior Test Engineer
ARRL Laboratory
Jan 15th 2020, 11:24


Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Follow up from an old posting. I located the noise and it was 1.7 miles from my QTH. The cause was a power pole where the cross arm bolt was arcing to a metal bracket. Once I identified the pole, the power company quickly found the problem. de W4DD, Atlanta area

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