E region of the atmosphere
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E layer, has ionization of around 106 free electrons. The layer is found at a height of around 60 to 90 miles (100-150 km), but its height varies according to the seasons and during the day and at night. The Heaviside layer reflects relatively long, low-frequency radio waves ranging from 100 kHz to 20 MHz. Also called the Kennelly-Heaviside layer and the E region of the atmosphere.