Two Great and Historic Leonid Storms

1998 and 2001


As Audio Recorded in New Mexico
Using the Forward Scatter Method
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Note to visiting Phonographers and Nature Recordists:

Radio meteor scatter is an ideal technique for observing meteors. Meteor trails can reflect radio waves
from distant transmitters back to Earth, so when a meteor appears one can sometimes receive small
portions of broadcasts reflected from radio stations up to 2000 km away from the observing site.
I won't try to explain the method here as it is a little complex but for those interested I shall refer you to:
http://www.imo.net/radio
If you have further questions I can try to answer or refer you to better information.

Thomas Ashcraft

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November 18, 2001  Leonid Fireball Swarms

Below are four short multi-transmitter reflection specimens recorded at 89.5 FM.
These were typical of the early part of the night, before saturation.

MLeo1118010739ushortie.mp3         21 seconds      509 KB
MLeonov1801_1044utpill89shorter.mp3    42 seconds    1 MB
MLeo1118010924shorthitslayers.mp3     31 seconds   750 KB
MLeo1118011015utreverend.mp3       24 seconds   574 KB

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Here are two half hour long recordings of the two peak periods of activity.
Note:  They are very large files, 42 MB each!

The 2nd reported Leonid peak, 1800 UT to 1830 UT, was recorded in daylight while the shower radiant was still above the horizon in New Mexico at that time.
There is a faint but evident WWV time stamp at the beginning and a clear time stamp at the end of the file.  1800 UT is 11 am Mountain Standard Time
and Leonid radiant was still above the western horizon then in daylight here. You can hear a lot of continuum flutter caused by the meteor trains as they
disintegrated and twisted in the upper atmospheres. Antenna direction was eastward but meteor reflections were coming from many directions.


This recording is mono.  89.5 FM    Note :   Large file!   42.7 MB
MLeo111801_1800ut2ndPEAK.mp3

The following recording begins at 0945 UT and ends at 1015 UT. When I extracted this section I thought that the 1st peak occurred around 1000 UT but
now I believe the actual visual peak was at 1020 UT. In any case, the radio was near saturated and an individual count of meteors was not possible.

Note :  Large File!   44 MB
MLeoNov18010945utpeakLONG.mp3
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Here is a general 2001 shower report from the International Meteor Organization
http://www.imo.net/node/134
http://sci2.esa.int/leonids/leonids2001/radio.htm

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1998 Fireball Storm

On November 17, 1998 the Leonid Meteor Shower produced a truly spectacular display of fireballs.
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This night's recordings were made in stereo using two separate radios, each with its own FM antenna.
Frequencies were 89.5 FM MHz and 91.1 FM MHz with antennas oriented east and northeast.
My observing location is north central New Mexico and I was receiving stations as far
away as central Illinois and possibly beyond, well over 1000 miles away.
 

Here are some audio specimens that I have extracted from the night's tape.
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To begin with:
Baseline radio continuum and short cluster of small meteors      18 seconds    433 KB
MLeo111798_0655utshort.mp3
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A quick sequence of fireballs with strong head echoes.
MLeo111798_0702uttone.mp3    38 seconds    897 KB
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Long meteor trails reflecting in multiple transmitters. Typical of the night.  
MLeo111798_0651utheadecho.mp3    1 minute 17 seconds      1.8 MB
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Saturation! Fireballs are striking with rapidity bouncing in multiple transmitters.
You can hear many stations simultaneously as fireballs strike one after the other.
You can also hear a sort of "swoosh-swoosh-swoosh" as meteor trains deteriorate and
the signal reflections dissipate. I believe there is a lot of ionospheric data in these recordings.
Note: This is a large sound file.
MLeo1117980724utsaturated.mp3    7 minutes 18 seconds        10.2 MB
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Information on the forward scatter method of meteor detection can be accessed at:
http://www.imo.net/radio

My own radio meteor equipment is simple but ultrasensitive and consists of:
Technics FM receiver, JVC FM receiver, Radio Shack FM yagi antennas
Panasonic stereo VCR for audio recording,
Sangean ATS-803 shortwave for WWV time stamping


Thomas Ashcraft
Radio Fireball Observatory
New Mexico


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