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RE: [wsjtgroup] Digest Number 755

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  • Matthew Chambers
    Could it be a BPL type system, I hear something very very similar on 2m and its part of the VLF Electric meter reading system in Macon Co. The meters use a VLF
    Message 1 of 1 , Sep 14, 2005
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      Could it be a BPL type system, I hear something very very similar on 2m and
      its part of the VLF Electric meter reading system in Macon Co. The meters
      use a VLF signal at 2-20 Hz but the microprocessors run on 144-148 MHz (not
      cool) there is a chance that some utilitys equipment has a microprocessor on
      the 50MHz band, I have notice that around here the meters have notch filters
      for the Public saftey bands, the local utility was unaware that the 144-148
      band was used by anyone, might be something similar there. Good luck finding
      and curing the problem. I still find 2m weaksignal very dificult and
      challenging. But it makes the contacts much more satisfiying knowing I did
      it over all the noise and QRM.

      73
      Matthew Chambers, KC�QEV -- MAC201
      ARRL Member -- ARES -- NWS Severe Weather Spotting Network
      Macon Missouri EM39ss -- Listening on 146.805, 146.520, 146.580, 144.200
      SWOT #3468 Member WSJT-Group
      Exploring VHF Weak Signal

      On Tue, 13 Sep 2005, wsjtgroup wrote:

      Message: 4
      Date: Tue, 13 Sep 2005 09:31:45 -0500 (CDT)
      From: "Jonathan L. Rosner" <rosner@...>
      Subject: Re: Spurious 6 m signal


      This sounds rather similar to what we have been experiencing at the
      University of Chicago for the past two years. I have not tried to find
      the source, figuring it was a new piece of apparatus somewhere in the
      University for which there would be no remedy.

      Joe, maybe you could record a short .wav file of the sound this thing
      makes and send it to us on the reflector. Just a guess: Is the signal
      coming from the direction of the University? (Maybe the Engineering
      building?)

      As a result of this signal I have had to choose my 6 meter FSK441A
      frequencies VERY carefully. There is still an S5 pulsing broadband noise
      all up and down the band.

      73,
      Jon WO9S
      --
      Jonathan L. Rosner Phone: 773-702-7694
      Enrico Fermi Inst., U. Chicago Fax: 773-702-8038
      5640 S. Ellis Avenue rosner@...
      Chicago, IL 60637 USA or rosner@...

      ----------------------------------------------------------------------
      On Tue, 13 Sep 2005, Joe Taylor wrote:
      This is perhaps a rather odd question to post on this reflector, but
      there are lot of smart people here, and someone here just might know
      what I'm talking about.

      Several months ago an odd spurious signal turned up here on the 6 meter
      band. I have been hoping it would go away, but maybe the time has come
      to track it down. I can peak my antenna on it, so I know the direction
      fairly well, but so far I have no idea how far away the source may be.

      The signal has the following characteristics. There is a main "carrier"
      at 50.161 MHz, and many sub-carriers at intervals of about 3.7 kHz up
      and down the band from there. Up the band, the same thing occurs
      centered on 50.236, with many sidebands up and down from there.

      Between all of these sidebands or sub-carriers there is broadband noise,
      and the noise is modulated on and off with a square wave. The period of
      the square wave is about 0.83 seconds.

      The signal is fairly strong, so the 6 meter band is pretty well messed
      up around here. Does anyone have a notion as to what this intruder on
      our band may be?

      -- 73, Joe, K1JT
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