Terrestrial Noise

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Noise, Terrestrial


electrical fluctuations in a receiving antenna caused by the heat radiation of the earth in the radio spectrum, which, like atmospheric noise, worsen the quality of radio reception (seeFLUCTUATIONS, ELECTRICAL).

A quantitative characterization of terrestrial noise is given by the noise temperature, which is equal to the product of the physical temperature of the absorbing layer of the earth (≈300°K) and the coefficient of absorption of this layer. The latter depends on the orientation of the antenna with respect to the earth. Terrestrial noise is comparatively great at small altitudes of the main lobe of the radiation pattern of a high-directional antenna placed on the earth and in those cases where an antenna mounted on a low-flying object is directed at the earth. If the main lobe is directed at the zenith, terrestrial noise is usually negligible.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
A radio telescope on the far side could avoid terrestrial noise. That's a good use for dirt--put it between you and Earth.
During operation, even small amounts of terrestrial noise can be picked up by the antenna and thwart system readings.

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