Individual #Appleton_layer__F_layer__F_region the highest region of the ionosphere (from 90 to 600 miles up) that contains the highest concentration of free electrons and is most useful for long-range radio transmission
instance of: #region.location
part of: #ionosphere the outer region of the Earth's atmosphere; contains a high concentration of free electrons
part of: #atmosphere the mass of air surrounding the Earth; "there was great heat as the comet entered the atmosphere"
part of: #Earth.terrestrial_planet__earth__globe the 3rd planet from the sun; the planet on which we live; "the Earth moves around the sun"; "he sailed around the world"
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