The lowest layer of the Earth's ionosphere. It is between about 95 and 130 kilometers above Earth's surface. Also called the E Layer. more

A daytime region of the ionosphere, forming roughly between heights of 70 and 100 miles. Ionization in the E region is caused mainly by x-rays. Other sources of E region ionization include trails from incoming meteors and electrically charged sub-atomic particles from the sun. Transient patches of ionization in the E-region, known as "sporadic E" or Es, can often refract HF and VHF signals over great distances (500-1500 miles).