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Space-Wave Intensity

August 15th Fact-of-the-Day

A horizontal half-wave dipole transmitting antenna radiates energy toward both sky and earth. The portion radiated toward earth reverses phase when it reflects skyward off the earth's surface. Reflected and direct space-wave components are of equal magnitude and opposite phase when an antenna is at the surface of the earth and therefore produce a zero resultant space wave. The space-wave becomes increasingly stronger as the height of the antenna is increased to moderate heights, because the additional distance traveled by the ground-reflected component shifts its phase from cancellation at all vertical angles to reinforcement at one or more vertical angles. ©2004 Martek, International. All rights reserved.


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