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F layer[′ef ‚lā·ər]
An ionized layer in the F region of the ionosphere which consists of the F1 and F2 layers in the day hemisphere, and the F2 layer alone in the night hemisphere; it is capable of reflecting radio waves to earth at frequencies up to about 50 megahertz.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
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