Callsign
ad: elecraft
Results 1 to 10 of 10

Thread: Looking for advice on power line RFI

ad: L-HROutlet
ad: l-assoc
ad: l-WarrenG
ad: l-gcopper
ad: l-rl
ad: l-Heil
ad: l-Waters
ad: l-innov
ad: l-tentec

Contribute
to QRZ

  1. #1
    Join Date
    Oct 2005
    Location
    Del Rio, Texas
    Posts
    4,755

    Default Looking for advice on power line RFI

    I'm looking for advice on locating overhead power line RFI that is contributing to the noise level here at my qth located in a 50 yr old (read original distribution system) city neighborhood. Last time I dealt with power line RFI was easy as I was out in the country with no neighbors for a mile so tromping up and down the power line with my trusty AM pocket portable was easy work to find the offending poles. AEP, the power company, here and at the old qth were very cooperative and fixed every issue I told them for approximately one mile around improving Now living in a Texas neighborhood I am afraid of gun fire and possible police harassment for walking the alleyways trying to find RFI besides some of the alleys are fenced off illegally. Is an MFJ-856 the way to go or is there a more economical effective way to locate the poles that noise is coming from? In the city what is a reasonable expectation regarding the distance from my qth to noisy poles that the power company should be expected to take action? a block, a mile, ??. The community hospital is one block away from my qth and there is something inside one of the outbuildings, not a treatment area, that obliterates my AM vehicle radio reception worse than any power line when I drive besides the building. Are hospitals required to take steps to reduce RFI to amateur radio installations?

    Besides moving back to the country which I dearly miss but unfortunately can not do, any advice from those who have dealt with RFI "in town" would be appreciated.

  2. #2

    Default

    The ARRL website has the best advice. I tracked down a pole in my neighborhood with a arrow antenna and an HT using VHF AM. I had also used an oscilloscope to look at the noise cycle. This one was loud enough that the HT with a whip pretty much verified it when you drove by or stood under it. When I showed the utility company all this, they fixed it promptly but never told me the source. The utility company should fix any pole they own that is causing noise. Hopefully it is a pole and you'll only be dealing with the utility company.

    K4PP

  3. #3
    Join Date
    May 2001
    Location
    Roswell, NM DM73
    Posts
    2,889

    Default

    You have two commercial choices.

    MFJ has to models. One is attached to a 3 element beam, and the other is just a dipole. I have the latter and it works well considering the cost (<$100 delivered).

    The Xtal Set Society sells an ultrasonic device in kit form, complete with a lexan reflector. I don't own one, but a friend does, so I know it works very well once you get close enough (≈50 feet). The idea is, most noise is generated by a spark gap, and although you can't hear it aurally, the device can, and it mixes the noise down to an audible frequency. It is a kit, and depending on your skill, it takes about 4 to 5 hours to assemble. All of the surface mounting is already done, but you still have to solder a few things. Or, you can bite the bullet and spend $450 and get one assembled.

    Once is all said and done, getting the darn power companies to fix whatever it is, becomes the real problem! Good luck!
    Alan Applegate, KBG
    http://www.k0bg.com

  4. #4
    Join Date
    Jun 2011
    Location
    $FFFE
    Posts
    8,079

    Default

    Quote Originally Posted by K0BG View Post
    Once is all said and done, getting the darn power companies to fix whatever it is, becomes the real problem! Good luck!
    Maybe. I wrote down the number on the tag on the pole, and called Weenergies at 0:30 local time. I explained how I found it and told them the number. I got the impression they thought I was wearing a tin foil hat or something and that they were going to ignore it. A week later, I saw them with a bucket truck working on the pole, and the noise vanished. I now get the same noise, but it's very intermittent. Before, it was constant (for years). I assume the new noise is from a different source.
    73,CBM DOS V2,00,00

  5. #5

    Default

    FWIW our local power company is extremely responsive to this stuff.

    For me, they sent out two trucks and four guys and started replacing old insulators and couplings, and found a bad ground cable coming down a pole from the residential primary (7200V). Not sure exactly what fixed the noise, but when they were done, it was all gone and never came back. I was going to thank them, but by the time I got outside, they were gone!
    What if soy milk is just regular milk introducing itself in Spanish?

  6. #6
    Join Date
    Jan 2004
    Location
    Talladega, Alabama
    Posts
    4,893

    Default

    Call your local power company.They should come right out?
    Bryan, AC4BB
    Scio me nihil Scire: Socrates
    Psm:109:8

    "
    [h=1]A man who carries a cat by the tail learns something he can learn in no other way?[/h]Mark Twain.

  7. #7
    Join Date
    Jun 2005
    Location
    Mesquite, TX
    Posts
    455

    Default

    RFI problems are often related to mechanical damage such as bad connections or broken insulators. I have had pretty good luck with getting as close as possible and then mechanically stressing the poles (translation: hitting them with a 5 pound sledge hammer). When you start to hear a difference in the interference that corresponds with the mechanical stress, you are getting close. Of course, you mentioned that you are hesitant to walk around. So banging on the poles might not be a very good idea.

    Some electrical distribution companies have people on staff that are tasked with tracking down and remedying RFI. Here in North Texas, ONCOR has (Rr at least had. I haven't contacted them in a while.) such a crew. You have to do a little sleuthing beforehand to give them a place to start.

  8. #8
    Join Date
    Jun 2011
    Location
    $FFFE
    Posts
    8,079

    Default

    Quote Originally Posted by WY5V View Post
    RFI problems are often related to mechanical damage such as bad connections or broken insulators. I have had pretty good luck with getting as close as possible and then mechanically stressing the poles (translation: hitting them with a 5 pound sledge hammer). When you start to hear a difference in the interference that corresponds with the mechanical stress, you are getting close. Of course, you mentioned that you are hesitant to walk around. So banging on the poles might not be a very good idea.
    I fully expect banging on utility poles with a 5# hammer around here would get one in a lot of serious trouble.
    73,CBM DOS V2,00,00

  9. #9
    Join Date
    Oct 2005
    Location
    Del Rio, Texas
    Posts
    4,755

    Default

    Quote Originally Posted by KC9UDX View Post
    I fully expect banging on utility poles with a 5# hammer around here would get one in a lot of serious trouble.
    Here too. I can't fully access the entire alley ways let alone thump a pole. Not saying it doesn't work, it does ........ don't ask me how I know.

  10. #10
    Join Date
    Jun 2011
    Location
    $FFFE
    Posts
    8,079

    Default

    Quote Originally Posted by N5YPJ View Post
    Here too. I can't fully access the entire alley ways let alone thump a pole. Not saying it doesn't work, it does ........ don't ask me how I know.
    I think if I were so inclined, I'd have better chances bumping them with my car than hitting them with a hammer. I can't even imagine hitting the one at the end of my driveway with a hammer.
    73,CBM DOS V2,00,00

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •