Segnali VLF emessi dal bolide che ha colpito la Russia ?

Questa la relazione di Paul Nicholson sul gruppo VLF di Yahoo .
Uno dei tre osservatori impiegati per la triangolazione e' stato quello di Cumiana di Renato Romero .

Oggetto: Re: [VLF_Group] Re: Meteor Blazes Across Sky over Russia
Data: Sat, 16 Feb 2013 21:56:29 +0000
Mittente: Paul <paul@abelian.netcom.co.uk>
Rispondi-a: VLF_Group@yahoogroups.com
A: VLF_Group@yahoogroups.com


We had good recordings from the European receivers and the
analyser picked out 15 possible signals in the 25 seconds
leading up to the final flare.

Output of the analyser :

http://abelian.org/vlf/tmp/130215a.gif

Time axis is aligned so that 120 seconds is 03:20:31 which is
roughly the time of the final flare.

Each spike indicates a possible signal. The spikes at 108 and
118 seconds are weak calibration pulses, waveform and timing
simulated for a source at 55.05N,59.8E

I've looked carefully at all these hits and none are genuine,
they are a typical collection of chance alignments of sferics.

Approximate ranges of the receivers are

Todmorden: 3900km
Bielefeld: 3300km
Cumiana: 3800km

As an example, here is one of the false hits, occurring 21
seconds before the final flare and some 5 to 7 seconds before
the meteor became visible on cameras,

http://abelian.org/vlf/tmp/130215b.gif

The analyser has picked out the scruffy little pulse which
arrives at the center of this plot. It is barely above noise.
In these charts, the three signals are time shifted so that
a signal originating at 55.05N,59.8E will be aligned on the
time axis.

I'll keep the signals filed with all the other fireballs and
when the calculated track of the meteor is published I can
try again with the better coordinates. The software is being
improved so there's always a chance that later this or one of
the other 250 filed events will turn something up.

Paul Nicholson