Abstract
A VAST number of people are nowadays interested in one or other of the aspects of radio communication, and they are necessarily concerned with the manner in which radio waves are propagated around the earth's surface and to distances beyond the horizon. These and older students of the subject have become aware of the fact that such propagation is possible as a result of the existence of the ionosphere—those regions of the earth's atmosphere which become electrically conducting by ionization chiefly under the influence of ultra-violet radiation from the sun. It does not, however, require much delving into the subject to discover that the ionosphere is not simply equivalent to a metallic electrically conducting sheet in the same position at all times and seasons. It is rather in the nature of a series of partially conducting layers, one above the other, each varying in height and conductivity with time, and the lower layers sometimes shielding the upper ones from radio waves transmitted upwards from the earth's surface. Whether or no such upgoing waves are deflected back to earth from the ionosphere depends upon solar conditions, time of day, season of year, position on the earth's surface, and upon the frequency of the radio waves and the angle at which they are projected upwards from the earth.
Radio Waves and the Ionosphere
By T. W. Bennington. Pp. vi + 81. (London: Iliffe and Sons, Ltd., 1944.) 6s. net.
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Radio Waves and the Ionosphere. Nature 154, 413 (1944). https://doi.org/10.1038/154413a0
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DOI: https://doi.org/10.1038/154413a0