Loading ...
Sorry, an error occurred while loading the content.

May 01, 2013 sprite - radio - movie

Expand Messages
  • Thomas Ashcraft
    I am still getting my transient luminous event (red sprites and blue jets) capture system up and running for 2013 but am almost ready. I still have a small
    Message 1 of 7 , May 2 10:25 AM
    • 0 Attachment
      I am still getting my transient luminous event (red sprites and blue
      jets) capture system up and running for 2013 but am almost ready. I
      still have a small issue with my VLF-ELF receiver which is picking up my
      shortwave channel at 2.5 MHz ( WWV signals ) so I need to insulate better.

      Here is a sprite captured over west Texas, 365 miles away from my
      observatory with radio emissions.

      For the movie, the player can be expanded to full screen by pressing the
      button in the far right bottom of player after movie starts.
      http://www.heliotown.com/Sprite_May012013_035205UT.html

      If this movie does not play for anyone could you please let me know. It
      should play in all computer platforms.

      Thomas Ashcraft : Heliotown : New Mexico
    • Paul
      ... Thomas provides the location: 32.4717,-100.7439 and the timing: 2013-05-01_03:52:05.135 stroke 2013-05-01_03:52:05.138 sprite for this event. I pulled
      Message 2 of 7 , May 5 11:25 AM
      • 0 Attachment
        > http://www.heliotown.com/Sprite_May012013_035205UT.html

        Thomas provides the location:

        32.4717,-100.7439

        and the timing:

        2013-05-01_03:52:05.135 stroke
        2013-05-01_03:52:05.138 sprite

        for this event. I pulled the VLF signals from our six timestamped
        receivers and time shifted each one by the calculated propagation
        delay to the receiver. Putting them all together gives

        http://abelian.org/vlf/tmp/ta130501a3.png

        Top to bottom is:

        Todmorden
        Bielefeld
        Cumiana
        Sebring
        Hawley
        Marlton

        Due to the time shifting, the x-axis corresponds to the timing
        at the location of the lightning.

        Hawley was only 87km from the lightning and the signal clipped
        severely. It looks like it was the slow tail that was
        responsible for most of the receiver overload there.

        The more distant receivers are able to distinguish separate
        VLF bursts from the stroke (x=0.135) and sprite (x=0.138).

        Comparison of the three European receivers is interesting.
        Bielefeld suggests the slow tail dropped in frequency
        at x=0.142, Cumiana records a very different slow tail
        which is difficult to account for. Perhaps the rx
        overloaded there. We saw a similar response to another
        sprite last week. None of the three European receivers
        can agree on the waveform of the slow tail. All the
        receivers have different amplitude and phase response
        but you'd think they'd at least agree on the frequency
        components in the slow tail.
        --
        Paul Nicholson
        --
      • renato
        Interesting test! In my opinion there is not clipping in the Cumiana waveform acquiring. I think the graphs difference comes by bandwidth: the Cumiana
        Message 3 of 7 , May 5 1:24 PM
        • 0 Attachment
          Interesting test!
          In my opinion there is not clipping in the Cumiana waveform acquiring. I think the graphs difference comes by bandwidth: the Cumiana monitoring station works "in flat" starting from 2 Hz, without any high pass filter. The difference is very clear comparing the spectrogram of the signal coming from workstations: Cumiana is the only one that starts so low.

          Renato Romero


          --- In VLF_Group@yahoogroups.com, Paul <paul@...> wrote:
          >
          > > http://www.heliotown.com/Sprite_May012013_035205UT.html
          >
          > Thomas provides the location:
          >
          > 32.4717,-100.7439
          >
          > and the timing:
          >
          > 2013-05-01_03:52:05.135 stroke
          > 2013-05-01_03:52:05.138 sprite
          >
          > for this event. I pulled the VLF signals from our six timestamped
          > receivers and time shifted each one by the calculated propagation
          > delay to the receiver. Putting them all together gives
          >
          > http://abelian.org/vlf/tmp/ta130501a3.png
          >
          > Top to bottom is:
          >
          > Todmorden
          > Bielefeld
          > Cumiana
          > Sebring
          > Hawley
          > Marlton
          >
          > Due to the time shifting, the x-axis corresponds to the timing
          > at the location of the lightning.
          >
          > Hawley was only 87km from the lightning and the signal clipped
          > severely. It looks like it was the slow tail that was
          > responsible for most of the receiver overload there.
          >
          > The more distant receivers are able to distinguish separate
          > VLF bursts from the stroke (x=0.135) and sprite (x=0.138).
          >
          > Comparison of the three European receivers is interesting.
          > Bielefeld suggests the slow tail dropped in frequency
          > at x=0.142, Cumiana records a very different slow tail
          > which is difficult to account for. Perhaps the rx
          > overloaded there. We saw a similar response to another
          > sprite last week. None of the three European receivers
          > can agree on the waveform of the slow tail. All the
          > receivers have different amplitude and phase response
          > but you'd think they'd at least agree on the frequency
          > components in the slow tail.
          > --
          > Paul Nicholson
          > --
          >
        • john heath
          Hi Paul     Nice data collecting . Yes the slow tail seems to be a earth position dependent variable. One could entrain receiver differences but other than
          Message 4 of 7 , May 5 5:01 PM
          • 0 Attachment
            Hi Paul
             
             
            Nice data collecting . Yes the slow tail seems to be a earth position dependent variable. One could entrain receiver differences but other than Marlton they all seem to be the same receiver frequency response . What is different in the sky or ground at these different locations that would lead to such a different low frequency tail ? Or is it the aftermath of what fell to earth with a uneven distribution like the bits and pieces of a comet salt and peppered around in a random way ? A plasma burst could be like this with a strong head for the Sprite and later random smaller individual clouds of plasma falling from time .138 to .148 .
             
             
            John H

            --- On Sun, 5/5/13, Paul <paul@...> wrote:


            From: Paul <paul@...>
            Subject: Re: [VLF_Group] May 01, 2013 sprite - radio - movie
            To: VLF_Group@yahoogroups.com
            Received: Sunday, May 5, 2013, 11:25 AM



             



            > http://www.heliotown.com/Sprite_May012013_035205UT.html

            Thomas provides the location:

            32.4717,-100.7439

            and the timing:

            2013-05-01_03:52:05.135 stroke
            2013-05-01_03:52:05.138 sprite

            for this event. I pulled the VLF signals from our six timestamped
            receivers and time shifted each one by the calculated propagation
            delay to the receiver. Putting them all together gives

            http://abelian.org/vlf/tmp/ta130501a3.png

            Top to bottom is:

            Todmorden
            Bielefeld
            Cumiana
            Sebring
            Hawley
            Marlton

            Due to the time shifting, the x-axis corresponds to the timing
            at the location of the lightning.

            Hawley was only 87km from the lightning and the signal clipped
            severely. It looks like it was the slow tail that was
            responsible for most of the receiver overload there.

            The more distant receivers are able to distinguish separate
            VLF bursts from the stroke (x=0.135) and sprite (x=0.138).

            Comparison of the three European receivers is interesting.
            Bielefeld suggests the slow tail dropped in frequency
            at x=0.142, Cumiana records a very different slow tail
            which is difficult to account for. Perhaps the rx
            overloaded there. We saw a similar response to another
            sprite last week. None of the three European receivers
            can agree on the waveform of the slow tail. All the
            receivers have different amplitude and phase response
            but you'd think they'd at least agree on the frequency
            components in the slow tail.
            --
            Paul Nicholson
            --







            [Non-text portions of this message have been removed]
          • Thomas Ashcraft
            In future captures I will be looking for any possible sprite signatures in the spectrogram in the after crackle after the lightning pop. Also, I am
            Message 5 of 7 , May 8 7:00 AM
            • 0 Attachment
              In future captures I will be looking for any possible sprite signatures
              in the spectrogram in the "after crackle" after the lightning pop. Also,
              I am monitoring 2.5 MHz and in combination with VLF-ELF there probably
              is a radio image of the lightning-sprite complex in the broader
              spectrogram and also sound to the ear.

              Thomas in New Mexico


              On 5/5/13 12:25 44000, Paul wrote:
              > > http://www.heliotown.com/Sprite_May012013_035205UT.html
              >
              > Thomas provides the location:
              >
              > 32.4717,-100.7439
              >
              > and the timing:
              >
              > 2013-05-01_03:52:05.135 stroke
              > 2013-05-01_03:52:05.138 sprite
              >
              > for this event. I pulled the VLF signals from our six timestamped
              > receivers and time shifted each one by the calculated propagation
              > delay to the receiver. Putting them all together gives
              >
              > http://abelian.org/vlf/tmp/ta130501a3.png
              >
              > Top to bottom is:
              >
              > Todmorden
              > Bielefeld
              > Cumiana
              > Sebring
              > Hawley
              > Marlton
              >
              > Due to the time shifting, the x-axis corresponds to the timing
              > at the location of the lightning.
              >
              > Hawley was only 87km from the lightning and the signal clipped
              > severely. It looks like it was the slow tail that was
              > responsible for most of the receiver overload there.
              >
              > The more distant receivers are able to distinguish separate
              > VLF bursts from the stroke (x=0.135) and sprite (x=0.138).
              >
              > Comparison of the three European receivers is interesting.
              > Bielefeld suggests the slow tail dropped in frequency
              > at x=0.142, Cumiana records a very different slow tail
              > which is difficult to account for. Perhaps the rx
              > overloaded there. We saw a similar response to another
              > sprite last week. None of the three European receivers
              > can agree on the waveform of the slow tail. All the
              > receivers have different amplitude and phase response
              > but you'd think they'd at least agree on the frequency
              > components in the slow tail.
              > --
              > Paul Nicholson
              > --
              >
              >
            • Paul
              ... in which channel 3 shows the waveform from Cumiana containing a large low frequency tail to the sprite sferic, quite different to the signal picked up at
              Message 6 of 7 , May 10 12:27 PM
              • 0 Attachment
                I wrote:

                > http://abelian.org/vlf/tmp/ta130501a3.png

                in which channel 3 shows the waveform from Cumiana containing a
                large low frequency tail to the sprite sferic, quite different
                to the signal picked up at the other receivers.

                Passing channels 1 to 3 (Todmorden, Bielefeld, Cumiana)
                through a 10 pole 80Hz high pass filter produces

                http://abelian.org/vlf/tmp/ta130501a4.png

                This shows that after the ELF stuff is removed, we get a normal
                looking long tail. It is not clear in the original because
                it is buried under a large component at a much lower frequency.

                It is not quite the same - the dominant tail frequency in
                channels 1 and 2 is around 390Hz but appears lower in channel 3.
                All three rxs are fairly close together compared to the distance
                to the sprite, so should receive roughly similar signals.

                We also see a 'frequency doubling' effect at Bielefeld in the
                early part of the long tail. It coincides with the strongest
                part of the slow tail. It occurs to me that this could be
                accounted for by FM downlink overmodulation.

                The signal from Cumiana is a very interesting puzzle.
                The unfiltered waveform doesn't have a proper zero crossing
                between 0.142 and 0.165 seconds which hints at a frequency
                component down at around 20 to 25Hz.

                This may be some kind of receiver overload, maybe not
                straightforward clipping but perhaps something like a shift
                of the ground rail. Or, it may be a genuine component of the
                sprite signal. None of the other receivers would respond much
                at 20Hz, only Cumiana has such a good low frequency response.

                Renato kindly sent me a wav file from his orthogonal induction
                coil receiver which records 230 stereo samples/sec. I have
                roughly aligned this with the E-field recording and plotted in

                http://abelian.org/vlf/tmp/ta130501a5.png

                The induction coil has a strong component at about 20Hz. The
                period roughly corresponds with the recovery time of the
                E-field ELF transient.

                I wonder if this ELF component is typical of sprites. Or was
                there something special about ta130501a? Does this provide
                a way to distinguish sprites from non-sprite lightning (they
                both can have a long tail).

                We need to look at more sprites!
                --
                Paul Nicholson
                --
              • john heath
                  Hi Paul     ... coil receiver which records 230 stereo samples/sec. I have roughly aligned this with the E-field recording and plotted in
                Message 7 of 7 , May 11 8:42 AM
                • 0 Attachment
                   
                  Hi Paul
                   
                   
                  >Renato kindly sent me a wav file from his orthogonal induction
                  coil receiver which records 230 stereo samples/sec. I have
                  roughly aligned this with the E-field recording and plotted in

                  http://abelian.org/vlf/tmp/ta130501a5.png

                  >The induction coil has a strong component at about 20Hz. The
                  period roughly corresponds with the recovery time of the
                  E-field ELF transient.

                   
                  If I wanted to reproduce the green line , n/s magnetic data with a coil I would have to hold a magnet in my hand above the null point of the coil while turning the magnet in my hand and at the same time moving from + to null to - with respect to the n/s coil . If I assume the orthogonal coils are fixed in their positions then the source of the magnetic field must have moved in the sky from n to s or s to n to have the green line phase change with respect to the e / w coil . The e / w , blue line , is not getting out of phase with itself nor is it even close to its null point. To bad there was not a third coil to complete the 3 dimensions . One coil flat on the ground for up / down combined with n / s and e /w coils . This way the phasing of the n /s coil could be cancelled out by adding all x y and z coils . What I am saying in a round about way the source magnetic low frequency tail could be moving in the sky as trailing less energetic plasma falls
                  from space . Data from a true 3 dimensional orthogonal induction detector with 3 coils could be used to verify that the magnetic source is moving not stationary . If verified it would be a nice piece of the puzzle that some other bright spark could put to use .
                   
                   
                  John H 

                   
                  --- On Fri, 5/10/13, Paul <paul@...> wrote:


                  From: Paul <paul@...>
                  Subject: Re: [VLF_Group] May 01, 2013 sprite - radio - movie
                  To: VLF_Group@yahoogroups.com
                  Received: Friday, May 10, 2013, 12:27 PM



                   



                  I wrote:

                  > http://abelian.org/vlf/tmp/ta130501a3.png

                  in which channel 3 shows the waveform from Cumiana containing a
                  large low frequency tail to the sprite sferic, quite different
                  to the signal picked up at the other receivers.

                  Passing channels 1 to 3 (Todmorden, Bielefeld, Cumiana)
                  through a 10 pole 80Hz high pass filter produces

                  http://abelian.org/vlf/tmp/ta130501a4.png

                  This shows that after the ELF stuff is removed, we get a normal
                  looking long tail. It is not clear in the original because
                  it is buried under a large component at a much lower frequency.

                  It is not quite the same - the dominant tail frequency in
                  channels 1 and 2 is around 390Hz but appears lower in channel 3.
                  All three rxs are fairly close together compared to the distance
                  to the sprite, so should receive roughly similar signals.

                  We also see a 'frequency doubling' effect at Bielefeld in the
                  early part of the long tail. It coincides with the strongest
                  part of the slow tail. It occurs to me that this could be
                  accounted for by FM downlink overmodulation.

                  The signal from Cumiana is a very interesting puzzle.
                  The unfiltered waveform doesn't have a proper zero crossing
                  between 0.142 and 0.165 seconds which hints at a frequency
                  component down at around 20 to 25Hz.

                  This may be some kind of receiver overload, maybe not
                  straightforward clipping but perhaps something like a shift
                  of the ground rail. Or, it may be a genuine component of the
                  sprite signal. None of the other receivers would respond much
                  at 20Hz, only Cumiana has such a good low frequency response.

                  Renato kindly sent me a wav file from his orthogonal induction
                  coil receiver which records 230 stereo samples/sec. I have
                  roughly aligned this with the E-field recording and plotted in

                  http://abelian.org/vlf/tmp/ta130501a5.png

                  The induction coil has a strong component at about 20Hz. The
                  period roughly corresponds with the recovery time of the
                  E-field ELF transient.

                  I wonder if this ELF component is typical of sprites. Or was
                  there something special about ta130501a? Does this provide
                  a way to distinguish sprites from non-sprite lightning (they
                  both can have a long tail).

                  We need to look at more sprites!
                  --
                  Paul Nicholson
                  --







                  [Non-text portions of this message have been removed]
                Your message has been successfully submitted and would be delivered to recipients shortly.