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Author Topic: Strong 80m noise  (Read 8825 times)
K0AP
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Posts: 141




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« on: December 13, 2012, 08:58:23 AM »

Hi fellow HAM’s,

since few months ago I am challenged by a very strong noise especially on 80m band. Although not that strong, the noise is present on all HF bands. When I use the NB (noise blanker) the noise goes away, then however the IMD kicks in and I get distorted audio from the close by stations. I wonder if I install the INRAD roofing filter I will resolve the IMD problem. I have an AM portable radio and walked around the neighborhood and pinpointed the source of noise coming from direction of the power lines two blocks away from my house. I called the power company (KCPL) and an engineer came. I showed him the noise on the AM radio and he agrees that it's coming from the direction of the power lines. He used his parabolic antenna to scan the power poles and said there is nothing wrong with the power poles but someone in the neighborhood has plugged in some noisy device in the wall and this noise is being re-radiated through the power lines. To me this (very strong noise) sounds like a physical arcing on one of the power poles. What do you guys think? I have posted video recording of the noise on YouTube so please take a look and let me know your opinion. Click on the link below to take you to the video.

http://www.youtube.com/watch?v=ugRNeGjjKyY

Thanks for your feedback in advance!

73 Dragan K0AP
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WX7G
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Posts: 6321




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« Reply #1 on: December 13, 2012, 11:26:35 AM »

Will an INRAD roofing filter help? Yes it will help keep stations outside the filter bandpass from pumping the noise blanker.

What is the noise level? Driving around mobile on 40 meters I have found that many residential areas have noise (from electronic devices in homes) of S-7 or higher. And when I get away from the city the noise drops to S-2. Unfortunately at my home it is S-6, is coming from many homes, and there is nothing I can do to reduce it.
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K0AP
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Posts: 141




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« Reply #2 on: December 15, 2012, 10:13:31 AM »

Will an INRAD roofing filter help? Yes it will help keep stations outside the filter bandpass from pumping the noise blanker.

What is the noise level? Driving around mobile on 40 meters I have found that many residential areas have noise (from electronic devices in homes) of S-7 or higher. And when I get away from the city the noise drops to S-2. Unfortunately at my home it is S-6, is coming from many homes, and there is nothing I can do to reduce it.

The noise level on 80m is S9+20. It was rainy last night and the noise was gone. The rain stopped and the noise started picking up again. At this moment it’s arcing (breaking) and still has not reached the continuous S9+20 level but I know that eventually it will. So, it looks like the moisture kills the noise. I know it's coming from the direction of the power poles but I don't know how to convince the power company to check on the power poles hardware and see if something is loose or missing. The guy from the power company keeps saying that the noise is created by some device in the neighborhood and is re-radiated via the power poles. He used his parabolic antenna and receiver to check the noise. He said he could not find the noise on his parabolic antenna and receiver but also said that his receiver is for VHF frequencies so it can't be used to scan the LF frequencies. On the portable AM radio the overwhelming noise on 80m is clearly present.

Dragan K0AP
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NO2A
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Posts: 841




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« Reply #3 on: December 15, 2012, 11:48:31 AM »

Maybe if you could locate the noise yourself with the am receiver,then call public service and meet them there. Hopefully they would do that.
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W5LZ
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Posts: 477




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« Reply #4 on: December 23, 2012, 08:29:07 PM »

It's also possible that the power lines themselves are the problem, especially if things clear up when it's wet.  It's typically caused by a 'loose' connection in the lines somewhere.  The power lines through my neighborhood were replaced several years ago and a lot of noise was 'gone'... for a while.  Then there started to be some noise come back and it gradually increased to a really noticeable level.  There was a crew come through later that 'maintained' (fixed) the lines and things cleared up again.  No, I didn't complain, but I'll bet someone else did!  (They were tightening the various connection on the new lines.)
I would really suggest you be sure of the source before making a pest out of yourself...
 - Paul
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WB0CJB
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Posts: 38




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« Reply #5 on: December 26, 2012, 12:09:33 PM »

After listening to the YouTube video you're having the exact same issue as I am, only mine has to deal with 40 meters (S9+15). The sound of the noise is the same and lately mine has been cutting out at times whereas sometimes it doesn't. I've had the local power company out twice to check this and they too haven't found anything.I too believe its something with the power grid but I won't contact the power company until I can have it pinpointed to beyond a shadow of a doubt where the problem occurs.My problem started about 4 years ago when I moved into my house and the noise would stop in March and start up in October or November.Then in the past couple of years the noise has become nonstop.Rainy weather did not affect it but lately the noise has become intermittent.In the summer when the temps hit 100+ the noise went away and even at 70 degrees the noise would mostly vanish.

Granted one of my rigs' NB does knock it out (but causes some IMD trash on CW signals down a few kHz from my frequency) but there still is a noise hash of around S7 which I have assumed is from a noisy flat screen TV or some consumer device that is poorly designed. Short of praying that the offending device will suffer an early demise I know I have virtually no chance of getting the owner of the offending device to replace it.But I have to locate the source first which will take time and footwork.I can deal with the hash noise but the power line (?) noise is the biggest offender and I want it cleared up.

I have killed the power in my own house so the noise is definitely coming from either a neighboring home or overhead lines/hardware.I haven't had any complaints from the neighbors about interference (they are either on cable or satellite) so I'm fortunate to be able to operate without any problems.I look forward to hearing about your problem and what you find out to be the problem.

Do you live in an older neighborhood or has there been recent new construction going on?My neighborhood is a relatively older one but my section is about 5+ years old.I wonder if the recent addition may have something to do with the way the power lines and poles were put in.

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K1DA
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Posts: 539




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« Reply #6 on: January 07, 2013, 08:14:18 AM »

Got any street lights stuck in the "start" mode?  One of the biggest noise generators these days seems to be pulse type battery chargers. 
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K0AP
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Posts: 141




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« Reply #7 on: January 07, 2013, 11:22:54 AM »

After listening to the YouTube video you're having the exact same issue as I am, only mine has to deal with 40 meters (S9+15). The sound of the noise is the same and lately mine has been cutting out at times whereas sometimes it doesn't. I've had the local power company out twice to check this and they too haven't found anything.I too believe its something with the power grid but I won't contact the power company until I can have it pinpointed to beyond a shadow of a doubt where the problem occurs.My problem started about 4 years ago when I moved into my house and the noise would stop in March and start up in October or November.Then in the past couple of years the noise has become nonstop.Rainy weather did not affect it but lately the noise has become intermittent.In the summer when the temps hit 100+ the noise went away and even at 70 degrees the noise would mostly vanish.

Granted one of my rigs' NB does knock it out (but causes some IMD trash on CW signals down a few kHz from my frequency) but there still is a noise hash of around S7 which I have assumed is from a noisy flat screen TV or some consumer device that is poorly designed. Short of praying that the offending device will suffer an early demise I know I have virtually no chance of getting the owner of the offending device to replace it.But I have to locate the source first which will take time and footwork.I can deal with the hash noise but the power line (?) noise is the biggest offender and I want it cleared up.

I have killed the power in my own house so the noise is definitely coming from either a neighboring home or overhead lines/hardware.I haven't had any complaints from the neighbors about interference (they are either on cable or satellite) so I'm fortunate to be able to operate without any problems.I look forward to hearing about your problem and what you find out to be the problem.

Do you live in an older neighborhood or has there been recent new construction going on?My neighborhood is a relatively older one but my section is about 5+ years old.I wonder if the recent addition may have something to do with the way the power lines and poles were put in.



Thanks for your input. I live in a 30 year old neighborhood and the power lines are underground. It is interesting that you mentioned the noise is gone in March and comes back again in November. Same here in that regard. The new update in my situation is that at this moment the noise is gone. I noticed that the day we got our first snowfall (no more than few inches) the noise disappeared. This was like 3-4 weeks ago. Now the snow has melted and almost completely gone but the noise has not come back yet, it's still gone too. I am not sure what is going on. Apparently the wet weather (snow) has killed the noise, at least for now but I hope it will be forever. Something is telling me the noise will be back again but I hope not. Last year 2012 has been extremely dry here in Kansas. Maybe the dry weather has impact on this but I am not sure why would that be the case.

73 Dragan K0AP
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VE3TMT
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Posts: 500




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« Reply #8 on: January 11, 2013, 09:23:42 AM »

Sounds like a streetlight arching. I had the exact same noise across the entire HF spectrum and it turned out to be a streetlight on the corner by my house. I walked the neighborhood with my portable Grundig receiver and just happened to see a streetlight go out. When the light went out the noise went away. As the ballast charged up and the light came on orange, you could see and hear the noise level pick up until it went out again. The local utility company was a little hesitant to fix it until I told them I hold a federally issued radio license and this noise was interfering with my reception.

The light was fixed within a week.
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WB0CJB
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Posts: 38




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« Reply #9 on: January 13, 2013, 09:51:29 AM »

The other day while coming home from work at 4:45 PM I noticed the streetlights had come on except for one (3 houses down from my house). Then one morning when I went to get the paper before I left for work I noticed that the streetlight in my next door neighbor's yard had shut off and had restarted (this was at 5:30 AM). I had one instance where a nearby streetlight a block away was turning off and on and I could watch it while listening to the noise build and drop on 80M. But in maybe your case its something close to but not exactly the simple issue of a street light turning off and on.

The point is that with the changes in humidity, moisture from rain and snow,  and temperature changes in the seasons are starting to point to a power grid issue.As I write this my own noise problem went away about 1:30 AM while I was listening to 80M. It had rained earlier that day but when I was listening the temperature outside was around 60 and dry conditions. Even the hash noise that I receive was intermittent so possibly that rules out a neighbor's TV. With a fairly high humidity level it could keep a coronal discharge from occuring. The rain and snow would and could have "washed" any dust coating off the hardware so that a carbon path to ground might be minimal. Which now leads to a temperature sensitive starter or light fixture. Since the noise changes with different weather conditions it only would stand to reason that a temperature sensitive light would maybe cause the problem. If the air was extremely dry could it allow a corona type discharge?

I went to QRZ.com and looked up your call. From the picture that I got I saw a power line in the background (am I correct?). Its very possible that you may have a power problem at least a block or two away. Being that your power lines are underground (my own service drop is buried) there still is a reason for that noise. With the previous post my own observation of the lights on my street has made me more aware of the streetlight could be the culprit, being that the lights are always connected to the power and are turned on by a starter (or timer?).

I used to live in your neck of the woods many years ago and have an idea of where you are located. Keep me posted on your search. Good luck!
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KF7CG
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Posts: 872




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« Reply #10 on: January 14, 2013, 11:29:00 AM »

Depending upon burial depth and soil conditions, buried power lines are not removed from the noise equation. If they are shallow and the ground is dry they can radiate.

Not quite the same but a parallel example, at one of the places where I had a station I got into the neighbors phones when we were having a drought, but as soon as the soil was moist the problem went away. The phone lines were only down about 6 inches and the ground was dry enough to crack.

Since we were all on wells the solution was, water the lawn.

KF7CG
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