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Re: [loopantennas] I need a loop antenna for tracking down power line noise on 15 meters

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  • Myamiphil
    Back when I was using the phone lines for internet, I was constantly being droppedĀ  by Earthlink... The phone company changed the line to the house, and the
    Message 1 of 18 , Jan 20, 2013
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      Back when I was using the phone lines for internet, I was constantly being dropped  by Earthlink... The phone company changed the line to the house, and the pair from the street junction box was changed twice. The seconnd time the tech told me he was just recycling used pairs that were traded out for similar reasons. That's when I learned that the copper phone lines on the pole were no longer being purged with nitrogen or whatever gas they traditionally used. The lines were being allowed to decay as cell phone were becoming the major source phone links. This was also way before Bells Fiber lines. They're still fine for phone connections but crap for ADSL. That's when I switched to cable for Internet. Been fine ever since.

      But it was noisy lines they gave me a very low input sig. Some freeware showed me that before I switched. Cable was a little bit of a problem in the beginning, but again a signal eval disclosed my house runs were part of the problem. They ran one line to my main computer location and then from there I had the house Ethernet switch. Never had a problem since.

      The main idea is that the electrical and phone services (copper or fiber) are not always perfect. Trying to prove things can be a little of a pain. An sometimes they are purposely letting the old hardware go down the tubes because its obsolete. No advantage to being at the end of a network run. Your signal is just poor. Electric can be just as bad.... Who knows how far you have to go to prove your  part of whatever circuit.

      I work in the hospital environment. One hospital admitted they they had noisy power at their input transformer. It was beyond their control. And that meant they had to contend with all sorts of AC signal quality issues when it affected all the computer operated equipment in the facility.

      I would think they electric company you choose has to contend with the same issues. You might buy your power from an environmentally friendly power company, but the power still comes over the same wires. If they're crappy so's your power no matter where it comes from.

      The home can be just a bad a source of noise as the outside world. Maybe worse. The X10 appliance controls I use in my house are going down the tubes too... But its not the electric company's fault. With all the wall warts and switching transformers these days, I'm generating tremendous noise within the house on the lines and in the air. I'm sure I'd see plenty of noise. But I can't afford to filter every device in the house... I'd go broke with all the chokes I'd have to buy.... Filtering isn't exactly required for home environments.  Ever since I did the environmentally correct thing and switched to CFs and LED lamps, my home control has gone down the tubes. Hate them if you like, but incandescents are becoming obsolete.

      Even beyond power supplies, there's plenty of noise sources coming from all sorts of computer operated devices. What doesn't use a computer these days! Both copper and electromagnetic environments are challenges.


      Best Regards

      Phil
      Lat: 40.8367633
      Long: -74.1768412



      From: kevin asato <kc6pob@...>
      To: "loopantennas@yahoogroups.com" <loopantennas@yahoogroups.com>
      Sent: Sunday, January 20, 2013 9:58 PM
      Subject: Re: [loopantennas] I need a loop antenna for tracking down power line noise on 15 meters

       

      >depending on where you were. The same with direction-finding it with portable radio and its ferrite antenna. The noise spread at varying strength all >along the line for a couple of km and 300 m wide. It was the worst between 500-2000 kHz. Nothing helped.

      That's pretty much a sweet spot for ADSL transmission from the Exchange Office to your home. The noise (digital signalling) will vary by frequency as ADSL is a spread spectrum transmission system. The signalling is to be contained within the twisted pair cabling but we all know how that works - impedance changes due to bad splices, protectors, and aging facilities (corroded terminals) will cause the cable pair to go unbalanced and let the signal leak at various points along the cable.

      73,
      kevin
      kc6pob





    • Mauno Ritola
      Thank you Kevin and Phil for your comments. In my case the biggest problem was the broken cable, when it was fixed, most of the noise disappeared. I have got
      Message 2 of 18 , Jan 21, 2013
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        Thank you Kevin and Phil for your comments. In my case the biggest problem was the broken cable, when it was fixed, most of the noise disappeared. I have got good advice from guys like Leif sm5bsz in the fight against noise and I think the situation is now good, please check online via sdrspace.com or Perseus network in eastern Finland. I hope we get underground fibre cable in the coming years, that will still improve the situation.
        Thanks for the bandwidth and now back to topic.

        73, Mauno

        21.1.2013 4:58, kevin asato kirjoitti:
         

        >depending on where you were. The same with direction-finding it with portable radio and its ferrite antenna. The noise spread at varying strength all >along the line for a couple of km and 300 m wide. It was the worst between 500-2000 kHz. Nothing helped.

        That's pretty much a sweet spot for ADSL transmission from the Exchange Office to your home. The noise (digital signalling) will vary by frequency as ADSL is a spread spectrum transmission system. The signalling is to be contained within the twisted pair cabling but we all know how that works - impedance changes due to bad splices, protectors, and aging facilities (corroded terminals) will cause the cable pair to go unbalanced and let the signal leak at various points along the cable.

        73,
        kevin
        kc6pob




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