HELP Needed - Major Electrical Noise Issue

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k5xk
Posts: 28
Joined: Sun Jan 05, 2020 10:58 am

HELP Needed - Major Electrical Noise Issue

Post by k5xk »

Noise Issues can be the bane of our beloved hobby! Craig Jones, KC5MXV, in Springdale, is experiencing extreme electrical interference at his QTH near Don Tyson Parkway and Butterfield Coach Rd, where the neighborhood enjoys underground utilities. Here are Craig's observations, which lead him to believe unless he is able to resolve the issue, he will be unable to pursue his goal of enjoying HF on-air activities...

[My comments were about all the electrical noise I pick up every time I listen to an AM radio station. I can barely hear AM radio inside the house. It is worse inside the house, for obvious reasons, but also pick it up outside when listening to an AM broadcast station in the car. I know this noise would be picked up by an HF receiver. Some antennas can tune this out depending on how the noise is polarized, horizontal vs vertical.

It is horrible right when I pull into the garage, and eases when I back out but still present. I have gone as far as turning off the main in the circuit panel, killing power to the whole house, and still receive a large amount of noise. All of the utilities in my neighborhood are underground, except for a couple of high voltage primary lines.

My only multi-band antenna option is the EFHW wire antenna, which is a good option, due to yard size and restrictions. I can't setup a 30 foot HF vertical antenna. The EFHW wire would have vertical and horizontal runs, almost certain to pick up the excessive noise.

HF equipment is definitely more expensive and complicated to setup than VHF. I'm a little hesitant to setup a station if all I am going to hear is power line noise. I know ham radio is all about experimenting, but some research up front can prevent a bad station setup later.

I upgraded my license last year and have my general class ticket now, but have never operated on HF. I had plans to get setup right after, but cost and technical issues have prevented this from happening. Any help you or the club could provide to assess the noise issue and antenna options would be appreciated. Any major equipment purchases would probably have to wait for now. I definitely don't want to invest in equipment until I can get the noise and antenna issues figured out.

Craig, KC5MXV
Email: mcjones994@gmail.com


If you have any suggestions or ideas to share with Craig (and our group), please post replies here on the forum, for the benefit of all readers.

Thanks/73, Ron K5XK

KC5MXV
Posts: 1
Joined: Thu May 14, 2020 6:33 pm

Re: HELP Needed - Major Electrical Noise Issue

Post by KC5MXV »

I was able to spend more time on this tonight and found two major sources of RFI inside the house. The first offender was the garage door opener. I am going to install a choke on the power cord to see if it helps. The second offender was the wall-wart transformer attached to the TV antenna amp. This was immediately removed and replaced. I'm almost wondering if it was radiating thru the TV antenna as this source was strong all over the backyard. Thanks everyone for the help on this. My next problem to solve is how to run the EFHW wire thru the yard.

KG5SEI
Posts: 1
Joined: Thu Feb 06, 2020 10:08 pm

Re: HELP Needed - Major Electrical Noise Issue

Post by KG5SEI »

How is your HF rig grounded? Is the ground for it bonded to the grounding system for your residential electrical service as per NEC?

Also, is the noise constant or only when transmitting and does your house have modern grounded outlets?

k5yh
Posts: 1
Joined: Sun Mar 01, 2020 11:25 am

Re: HELP Needed - Major Electrical Noise Issue

Post by k5yh »

Craig, you are very near my qth. I have underground utilities as well and I do not experience a high noise level, here.
I think you are on the right track as having an internal problem within your house. I have a copy of ARRL’s Bonding an Grounding that I can loan to you that might help you. My email is k5yh@arrl.net. Paul

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wb5l
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Re: HELP Needed - Major Electrical Noise Issue

Post by wb5l »

"I have gone as far as turning off the main in the circuit panel, killing power to the whole house, and still receive a large amount of noise. All of the utilities in my neighborhood are underground, except for a couple of high voltage primary lines."

If the power was off to the house, and you still have niose, that leads me to believe it's somewhere else. How far away are those high voltage primary wires? If you detect noise coming from those, you will need to contact the power company. They have crews that can fix any poor connections, etc.

k5xk
Posts: 28
Joined: Sun Jan 05, 2020 10:58 am

Re: HELP Needed - Major Electrical Noise Issue

Post by k5xk »

There was a similar issue posed to the Arkansas DX Association mail list a few months ago. Our friend Pat Patterson, W5VY (ex-WA5KAK),recapped some of the highlights for us, as follows. Our local friends Stan/K5VR and Jay/W5JAY described how a similar solution was derived. Good Stuff...thanks, Pat!
Ron, here’s a recap of the e-mail thread plus a couple of links to resources. Remember, internet search is you friend when it comes to finding info.

*****************************************************

Hi, just curious as to what was the signal level was on your S-meter?

The reason I am asking, I had 40 over S9 signal from powerline interference on 6 m and the problem was over 1/4 mile away! Finally with K5VR's help and his trusty Yaesu HT, with VHF AM mode, we not only traced the problem down for the power company, but showed them where the problem was!

After 3 years of putting up with the noise, they fixed it the next day!

More info. There could be more than one problem! Something this strong could have more broke hardware underneath the main noise culprit! So expect to call them more than once to fix all the problems.

Here are some things I would do.

1. Keep a log on who you talk to, note the date and also when they came out to trace down the problem.

2. Be kind and patience with who you talk to. This goes a long way in eventually fixing the problem!

3. If you have a scope, terminate the speaker output while feeding the scope's input and take a picture of the signature. Show this to engineer assigned to fix the problem. BTW, this seem to get my power company into the "fix it" mode more than anything else! You can measure the frequency of that pulse and that will confirm for sure the noise is powerline interference. My thanks to Mark K5OO for that suggestion and his help!

If your scope doesn't have a frequency counter built in you can measure the time and then invert the time into frequency. Please see attached file of what mine looked like on a typical dual trace scope. Most powerline engineers have seen this waveform many times before and be at the right frequency within a few hertz or so.

From listening to your MP4 there is no doubt in my mind it is nasty power line interference. If the noisy powerline is parallel to your beam, it can propagate unreal amount of distance!

Good luck and 73 de w5jay/jay..

**********************************************************

Steve,

Is the scope display the recovered audio from your rig? I see a scale factor of 30ms/div but can't see the divisions. Sounds like 60Hz plus harmonics. Does it have a time of day pattern? Does the amplitude vary when you spin your 6M yagi? That might give you a clue where it's coming from. As Rory pointed out, it sounds like RFI generated by arcing on a

Medium Voltage distribution line....13.8kV. Could be loose hardware, damaged surge arrestor, cracked insulator, etc. Just in case it's a battery charger, wal-wart power supply, etc. in your house, you can try selectively turning off breakers in your distribution panel to see if one of them kills the noise.

Good luck! 73,

Pat, W5VY

**********************************************************

That is a great point Pat, looks like his rig does have an audio scope, but not sure if it has a scale to measure the pulse width?

I am in the worse possible area, not only surrounded by residential powerlines, but have two overland transmission lines! One is from coal fired plant not to far from here.

At the time we bought this house, I wasn't thinking ham radio! Never again!

73 de jay..

************************************************************

Helpful Links:

www.arrl.org/files/file/RFI/ThompsonNoise.pdf
www.arrl.org/sounds-of-rfi
www.dxzone.com/catalog/Technical_Refere ... Reduction/

*************************************************************

I helped Wayne, WA5LUY, find some RFI a few months ago. Wayne has an old pocket transistor radio that has the Aviation band. He put it in a metal enclosure with an antenna jack and has a three element yagi cut for about 135MHz that he uses to localize noise from power lines. I have a ultrasonic sound detector that can help isolate to a particular pole or device on a pole. It takes some pretty good arcing for my ultrasonic detector to hear it.

My first step is to eliminate things in the home and the best way to do that is to selectively turn off breakers and note any drop in the noise. If you see a drop then start unplugging things on that circuit. Also just walking around with a 2M HT set to AM can give you an idea where noise is being generated. The ARRL RFI Handbnook is a good resource….every club should have one to loan out. Some of the info is a bit dated now but the concepts are still valid.

I was the telecom engineer for Ark Elec Coop for years and I had a nice Spectrum Analyzer and wideband test antenna I used to find RFI in sub-stations that was screwing up our wireless SCADA links. I always tried to position our link antennas to put most of the HV stuff behind the antenna but that didn’t always work. Every distribution transformer (13.8kV to 240V) has a “combination switch” which includes a surge arrestor ( a stack of Metal Oxide Varistors in series) a fuse and switch that can be opened from the ground with a “Hot Stick”. The MOV stack can be damaged by lightning strike surges…turning some of the junctions into diodes and RF generators. Loose hardware on poles can also cause problems. Noise from loose hardware and cracked/leaky insulators generally gets better when its raining. Pay attention to time of day, day of week, outside air temp/humidity, etc. and look for trends. Night watchman lighting photo-switches and also be a problem.

Holler if you have any questions.

73,

Pat / W5VY

patw5vy@gmail.com

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