Antenna - A detector of radio waves. The electric field of the radio wave induces a voltage in the antenna which is amplified by a radio receiver.
Asteroid - A small stony body a few meters to a few kilometers in diameter with orbits within the planetary system. Some asteroids cross the earth's orbit leaving debris which become meteors.
Comet - A stony and icy body which orbits the sun in a long elliptical orbit. Comets usually leave a debris trail in their orbit which become meteors when the earth crosses their orbit.
Constellation - A grouping of stars in the sky originally connected by lines by ancient people to suggest a shape. The constellation Leo looks like a lion (Latin "Leo" = "Lion").
Earth's Velocity - The earth's velocity in it's orbit is about 30 kilometers per second. This adds to the maximum meteor velocity of 42 kilometers per second to give a maximum 72 kilometer per second fall rate on the earth.
E-Layer - The layer of the earth's atmosphere at about 150 kilometers above the earth's surface. The E-Layer is part of the ionosphere. Almost all meteors burn-up in the E-Layer.
FM Radio Band - The frequencies between 88 and 108 megahertz set aside for public broadcasting. The FM Radio Band is withing the range of frequencies useful for meteor detection.
Forward Scatter - The reflection of radio waves from the E-Layer in which the E-Layer acts as a mirror to bounce the signals which would have escaped into space back to the earth.
Frequency - The rate at which the electric field in a radio wave changes direction. It is expressed as cycles per second. The frequency is related to the wavelength and the speed of light (c) by frequency = c/Wavelength
Geminid Meteor Shower - A meteor shower which occurs around December 13 each year. The meteors appear to come from the constellation Gemini. The source of the Geminids is unknown.
Ionosphere - The region of the earth's atmosphere which is naturally ionized by ultraviolet light from the sun. The upper layers of the ionosphere reflect radio waves below about 30 megahertz.
Leonid Meteor Shower - A meteor shower which occurs around November 16 each year. The meteors appear to come from the constellation Leo. The source of the Leonids is the debris of the comet Tempel-Tuttle (1866 I).
Leonid Rate - 1966 - 100,000 per hour; 1996 and 1997, 80 per hour; 1998 prediction was 3,000 per hour with a maximum at 1900 UT (2:00 PM EST) on November 17th.
Meteor - A small aggregate of stony or dust-like grains of about one gram weight and a fraction of an inch in diameter. They are the remnants of comets and asteroids.
Meteor Scatter of Radio Signals - Meteors were discovered to scatter radio signals in the E-Layer by British scientists in 1932.
Meteor Shower - A fall of meteors at a rate significantly higher than the sporadic meteor rate.
Meteor Storm - A meteor shower with a very high rate (1000 per hour)
Meteor Velocity - The highest meteor velocity is about 42 kilometers per second. Higher velocities are not possible since they exceed the escape velocity of the solar system.
Meteorite - A meteor which doesn't burn-up completely in the atmosphere and impacts the earth. About 25 meteorites per year impact the United States. About 2000 meteors per year impact the earth.
Radiant - The point in the sky from which meteors seem to come (radiate). A meteor shower is named after the constellation in the sky where its radiant is located.
Sporadic Meteor - A meteor which comes from the background debris in the planetary system. This background comes from old comets.
Yagi Antenna - A type of directional antenna named after its Japanese inventor. It is commonly used for FM and TV reception. The elements are called directors and reflectors. These direct and reflect the radio waves.
Comments and technical questions can be addressed to me care of my father, Devlin Gualtieri, at AlliedSignal Research & Technology, Morristown, NJ.