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Still gathering Information

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  • Ken Smith
    I am still trying to gather information on what may be causing these problems. Local monitoring I don t see things as abnormal except maybe two carriers. These
    Message 1 of 3 , Aug 31, 2008
      I am still trying to gather information on what may be causing these
      problems. Local monitoring I don't see things as abnormal except maybe
      two carriers. These carriers has digital modulation on them but could
      be some sort of wireless remote monitoring. I'm checking FCC data
      bases for the spectrum of these. This is time consuming but I hope I
      run onto something. I am still trying to find these GWEN towers and
      located a person that knows a lot about them. I sent a email to him
      but have not heard back yet. I have got the call letters from several
      and running it through the FCC data base to see if they are still
      active or not.
      The only item I am seeing and have for some time is the AC Line
      frequency of 60 Hertz, appears to be modulated and most of it happens
      at night. During the day, I see it but at night is seems there is more
      than usual. I don't have the right sensors to monitor this yet but i
      will get them soon and will try to get a graph over a 24 hour period.
      I wish I had one person on the west coast and one on the east coast
      that could write down the times they hear this hum the loudest and
      sort of compare the times, this should give us an idea of if its only
      during the night time that this happens. This still may be an AC
      problem of heavy current draw during the daytime hours.

      Ken
    • Tom Becker
      ... frequency of 60 Hertz, appears to be modulated and most of it happens at night. The 60Hz signal itself cannot be directly modulated, but there are many
      Message 2 of 3 , Aug 31, 2008
        > ... The only item I am seeing and have for some time is the AC Line
        frequency of 60 Hertz, appears to be modulated and most of it happens at
        night.

        The 60Hz signal itself cannot be directly modulated, but there are many
        signals that are carried on the AC line and are synchronized to it.
        Here is a spectrum (from Spectrum Lab) of a few minutes of mine, for
        example, detected with a VLF receiver. The top blue band is amplitude;
        the two black-background charts represent before (upper chart) and after
        (lower) removal of the 60Hz components.
        http://rightime.com/VLF/60SecAndTWACS.jpg

        Beyond the vertical spikes that are caused by lightning (the reason for
        the receiver), the lower chart clearly shows several line-borne
        signals. The strongest here is caused by a modulation scheme used to
        read electric meters, called TWACS. A few strong TWACS calls,
        originated at the substation that serves us about a mile away, are shown
        at the right end of this period, and the entire chart shows ghosts of
        more distant and weak TWACS signalling. Each ~5-second burst of TWACS
        carries about 32 bytes of data over several miles of distribution. As
        you suggest, TWACS - at least here - is most active at night, when every
        meter on the local distribution network is read over 10 hours or so.
        Bursts of TWACS data also appear every 15 minutes throughout the day.
        You can listen, in fact, to my VLF receiver, in real time; you will hear
        TWACS if you listen long enough, and you can occasionally hear other
        line-borne signals, too. http://67.207.143.181/vlf9.m3u

        Despite being very common, TWACS surely is not a contributor to The Hum
        since it is so transient.


        Tom
      • Ken Smith
        Thanks Tom, I don t see those TWACS as you call them on the AC line. I guess that technology has not made it to WV yet. I m glad you recorded that because now
        Message 3 of 3 , Aug 31, 2008
          Thanks Tom,
          I don't see those TWACS as you call them on the AC line. I guess that
          technology has not made it to WV yet. I'm glad you recorded that
          because now I know what they will look like. They still read the
          meters here manually in this whole area. Yes the spikes are caused by
          lightning, turning on and off switches, and equipment. If you want to
          see some real junk, record a section of a new High Efficiency washing
          machine. You talk about pulse modulation that is weird.
          Yes I hear that raspy sound I guess its the TWACS you talked about. I
          going to try and load that up in my spectrumlabs and watch it.

          Ken

          --- In humforum@yahoogroups.com, Tom Becker <gtbecker@...> wrote:
          >
          > > ... The only item I am seeing and have for some time is the AC Line
          > frequency of 60 Hertz, appears to be modulated and most of it
          happens at
          > night.
          >
          > The 60Hz signal itself cannot be directly modulated, but there are many
          > signals that are carried on the AC line and are synchronized to it.
          > Here is a spectrum (from Spectrum Lab) of a few minutes of mine, for
          > example, detected with a VLF receiver. The top blue band is amplitude;
          > the two black-background charts represent before (upper chart) and
          after
          > (lower) removal of the 60Hz components.
          > http://rightime.com/VLF/60SecAndTWACS.jpg
          >
          > Beyond the vertical spikes that are caused by lightning (the reason for
          > the receiver), the lower chart clearly shows several line-borne
          > signals. The strongest here is caused by a modulation scheme used to
          > read electric meters, called TWACS. A few strong TWACS calls,
          > originated at the substation that serves us about a mile away, are
          shown
          > at the right end of this period, and the entire chart shows ghosts of
          > more distant and weak TWACS signalling. Each ~5-second burst of TWACS
          > carries about 32 bytes of data over several miles of distribution. As
          > you suggest, TWACS - at least here - is most active at night, when
          every
          > meter on the local distribution network is read over 10 hours or so.
          > Bursts of TWACS data also appear every 15 minutes throughout the day.
          > You can listen, in fact, to my VLF receiver, in real time; you will
          hear
          > TWACS if you listen long enough, and you can occasionally hear other
          > line-borne signals, too. http://67.207.143.181/vlf9.m3u
          >
          > Despite being very common, TWACS surely is not a contributor to The Hum
          > since it is so transient.
          >
          >
          > Tom
          >
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