Radio Line of Sight

Variations in the atmosphere's refractive index with height cause the paths of direct radio waves between transmitting and receiving antennas to curve slightly downward so that radio line-of-sight conditions exist slightly beyond the horizon determined on the basis of a light ray being able to pass from transmitting to receiving antennas without intercepting the bulge in the earth's surface. This effect can be compensated for under average conditions by assuming the earth's effective radio radius is approximately 1.33 times its actual radius. ©2004 Martek International All rights reserved.

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