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Re: [VLF_Group] VLF6 stream switched from MP3 to Ogg/Vorbis

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  • Paul
    Users of vlfrx-tools (0.4d or later) can downlink the timestamped versions of the streams directly with vtvorbis. To copy into local buffers, # Bielefeld,
    Message 1 of 2 , Jan 11, 2012
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      Users of vlfrx-tools (0.4d or later) can downlink the
      timestamped versions of the streams directly with
      vtvorbis. To copy into local buffers,

      # Bielefeld,
      vtvorbis -d -n67.207.139.49,4406 @vlf6

      # Todmorden (ch1), Bielefeld (ch2),
      vtvorbis -d -n67.207.139.49,4416 @vlf16

      # Todmorden (ch1), Marlton (ch2),
      vtvorbis -d -n67.207.139.49,4427 @vlf27

      If you want to run vtevent, use separate instances
      and event directories for each channel of the
      paired streams, eg something like

      mkdir -p /ev/vlf1 /ev/vlf6
      vtevent -vd /ev/vlf1 @vlf16:1 &
      vtevent -vd /ev/vlf6 @vlf16:2 &

      and so on. Mutually detected whistlers can be
      joined thus,

      wh=1326324680
      vtjoin /ev/vlf1/$wh.vt /ev/vlf6/$wh.vt $wh.joined
      vtsgram -p150 -s '-z50 -Z-30' $wh.joined | display -

      To experiment with ATD, select a band where the whistler is
      strong, and use vtfilter and vtcat to crop out the whistler

      vtfilter -hbp,f=4000,w=3000 $wh.joined |
      vtcat -S2 -E1 > $wh.cropped

      so that wh.cropped is limited to a particular
      F and T rectangle. Then cross-correlate

      # coherent
      vtcmp -mcor -w0.01 wh.cropped > data

      # or by envelope (0.4e required)
      vtcmp -mcor -w0.01 -r -F1, wh.cropped > data

      and data is 2-column ascii.

      The $wh.txt file contains a K= value where sqrt(K) = dispersion.
      Whistlers (extrapolated if necessary) cross 8kHz at 2.05 seconds
      into the $wh.vt event file. Reverse the Eckersley dispersion
      formula to estimate the offset to the causative sferic.

      Well, have fun.
      --
      Paul Nicholson
      --
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