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Meteor burst communication relies on the phenomenon of reflecting radio waves off
the ionized trails left by micrometeors as they enter the atmosphere and disintegrate.
Billions of dust-size meteor large enough to give usable trails enter the atmosphere
each day.
The operational principle is as follows: the Master Station transmits a continuous,
coded signal, usually in the 40 to 50 Mhz region (Low Band VHF). When a meteor appears
in the proper location, it reflects that signal to a receiving Remote Station. The
Remote Station decodes the signal, turns on its transmitter and reflects a signal
back along the same path to the Master Station. Information can be sent in either
direction until diffusion reduces the electron density in the trail to a value too
low to sustain reflection.
The maximum length of a single-hop link is about 1600 kilometers, a distance determined
by the height of the meteor trail and the curvature of the earth. The typical meteor
trail has a useful duration of a few hundred milliseconds, while wait-times betweens
suitably located trails can range from a few seconds to minutes depending on the
time of day, time of year, and system design factors. Hence, the data transfer consists
of bursts of high data rate transmissions, which can be hundreds of characters,
separated by a period of silence. One important by-product of the burst characteristic
is the ability of many links to share a common transmission frequency - an important
feature in data collection systems.
The exchange of information can be in either direction. Data can consist of short
messages such as sensor data readout, coded messages of up to several hundred characters,
text messages of a few words, or long messages achieved by splicing together the
transmission of successive bursts. In these applications, average throughputs of
up to several hundred words per minute are achieved with relatively simple equipment.
The performance of a meteor burst link is defined as the "waiting time" required
to transfer a message between two stations at a specified reliability. The primary
system parameters that will influence this waiting time are operating frequency,
data rate, transmitter power, antenna gain, and receiver threshold level.
Meteor burst communications systems can be employed effectively for both point-to-point
services and multiple station networks for ranges up to 160-0 kilometers. For extended
ranges, relay stations are employed using data store-and-forward techniques. The
meteor burst system is fully automated and simple to operate. It's rapid deployment
capability makes it ideal for disaster and emergency communications.
Meteor burst communications has proven to be a cost-effective, dependable communications
service - without recurring leased circuit costs.
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