18-06-2012, 03:07 PM
Meteor Burst Communications
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INTRoDUCTION
(U) The idea of bouncing radio signals off meteor trails and back to earth to the
intended receiveris not new. Since the early 1940s various communicators have wrestled
with the possibility. From these early studies, workable systems have evolved until today
it is not uncommon for amateur radio operators (hams) to use this method of
communicating. How is it possible to use a meteor the size of a grain of sand to reflect a
radio signal to its intended receiver? Let us begin with the meteor.
THE METEOR
(U) The meteors we will concem ourselves with orbit around the sun in a path that
coincides with the earth's. These meteors occur at a rate of two to eight billion daily or
roughly 50,000 per second. As these meteors catch up with the earth-or are overtaken by
it, they enter the atmosphere at a speed of 10 to 75 kilometers per second. The friction
caused by the meteor colliding with the atmosphere results in the vaporization of the
. meteor.
PROCEDURE
CURvEsAREHOURI.Y AVERAGERATESFORTHREE·MONTH
PERIODS,CENTEREDONTHEDATESINDICATED.
(U) AUMBC systems consist of a master station and one or more remote stations or
sensors. Hardware at both the master and remote station usually consists of a small laptop
computer terminal with storage for message bufTering,a transmitter, receiver, and
antenna. Frequency usage can range between 20 and 120 MHz. Most systems operate in
the 40 to 50 MHz range, which allows the use of smaller antennas. Transmissions can be
DlSADVANTAGES
(U) The most obvious disadvantage of using Meteor Burst Communications is the very
low data rate. The keying speed of the burst is actually quite fast, 2.0 to 4.8 kilobits per
second, but because of the wait time involved in finding a usable meteor trail, most
systems average only about 100 words per minute of actual data. If a user needs to
transmit large volumes of data, MBC are probably not the right choice. MBC would,
however, make an excellent back-up system for high volume users.
either simplex, half-ciuplexor full-duplex.