Difference between revisions of "Whistling Meteor"
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Whistling Meteor
</dt>
Name applied to a radio
meteor when a detection system is used in which the presence of the meteor
is indicated by a rapidly changing audiofrequency
radio signal.
</dd>
The maximum reflection of a radio signal from a radio meteor occurs
when the ion column is perpendicular to the line from the column to the
transmitter-receiver. During the approach of the meteor to this position, the
Doppler effect causes a change in the frequency of the reflected signal. When
the reflected signal frequency is then combined with the transmitter
frequency, the difference between the transmitted and reflected frequencies
produces an audiofrequency beat. The audiofrequency beat, when amplified and
fed to a loudspeaker, allows the meteors to be heard as a high-pitched whistle
which rapidly falls to zero frequency as the meteor trail becomes normal to
the line of sight. [[/a>|/a>
]]
References
This article is based on NASA's Dictionary of Technical Terms for Aerospace Use
