Dear Misaki Yoshitake,
Thanks for your message.


<3xt1.wav> is the sound of a high speed morse code signal, reflected
from the ionized trail of a meteor. It was sent from amateur radio
station UZ2FWA to my own radio station DK3XT. Distance between
the two stations is about 1050km. It is a record of what amateur
radio operators call a "burst", and it actually contains readable
information !
The term 1200lpm stands for 1200 letters per minute (or 20 letters
per second) in morse code.
This high speed morse code is generated by a computer program, then
fed into a VHF-transceiver on 144MHz.

Before beginning a "meteorscatter test" both stations have to agree
upon the exact frequency and the exact timing.

-Then
station (1) continuously transmits a high speed morse code text
-while
station (2) listens, and continously records the incoming signals
on a high speed tape recorder
After, say, five minutes, both stations switch positions :
-now station (2) transmits
-while station (1) listens

When a meteor happens to cross the line between both stations,
a small (sometimes a large) fraction of the signal will be
scattered forward and creates that "burst". For a small fraction
of time you'll actually hear the other station's signal reflected
from the meteor.

This play of switching between transmit and receive goes on
until
enough letters have been reflected to actually read the entire
message.

As I said, that "burst" contains readable information in morse code !
No human being can decode morse code at a speed of 1200lpm, so you
have to s l o w d o w n the sound file about 8 times.
1200/8=150lpm. A trained human ear can decode morse code at 150 letters
per minute; a not-so-well-trained ear will at least hear some morse
code. Now, when you slow down <3xt1.wav> 8 times, you'll hear some
morse code letters that decode to "DK3XT UZ2FWA R 26"
(best after the 2nd Doppler).

Now you have a piece of information, that has been sent to and
reflected from a fast moving celestial object...

I hope you have kept the files <3xt1.exe> and <3xt1slo.exe>

<3xt1.exe> is a self-extracting file, extracts to <3xt1.wav>.
is a self-extracting file, extracts to <3xt1slo.wav>

<3xt1slo.wav> is <3xt1.wav>, only it is 8 times slower !


For the question of measuring meteor's speed as they travel through
the atmosphere : I have never measured their speed. I guess, it can
be done when a distant station continously transmits a signal
modulated with a tone of known frequency, and you record and measure
the tone's frequency at the beginning and the end of the Doppler.

Common knowledge has it that meteor's speed vary from 30km/s - 90km/s
at altitudes of 70km - 110km.

If you'd like to see daily measurements of meteor's altitude and angular
distribution, turn to the page of the SKYMET meteor radar of
the University of Rostock (Northern Germany) :
<http://www.ionosonde.iap-kborn.de/sky_main.htm>


I hope, that has been of a little help -
greetings to you and to your math students !


Bernie Gapinski dk3xt/ab7iy <dk3xt@darc.de> <dk3xt@qsl.net>
<http://www.meteorscatter.net>
"Make More Miles On VHF"
<http://www.qsl.net/dk3xt>