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The Size of Ionospheric Fresnel Zones in Long Wave Propagation

其他書名	J.H. Crary, D.D. Crombie
出版	U.S. Department of Commerce, Environmental Science Services Administration, Institutes for Environmental Research, Institute for Telecommunication Sciences and Aeronomy, 1967
URL	http://books.google.com.hk/books?id=AeoOrgEACAAJ&hl=&source=gbs_api

註釋For a localized depression of the ionosphere to have an effect on the propagation of radio waves comparable to that of a uniform depression of the same depth overing the whole path, it must have horizontal dimensions comparable with the size of a Fresnel Zone. Curves showing the size of the Fresnel Zone in the ionosphere at frequencies of 10, 20, 100, and 300 kc/s for ionosphere heights of 30, 50, 70, and 90 km are given for distances out to the optical horizon.