E layer
= E layer
{c}
The E layer is a main region of the <ionosphere> below the <F layer>. The 1924 <Appleton-Barnett radio interference experiment> concerns this lower region.<The Ionosphere by Edward Victor Appleton>[Edward V. Appleton, The ionosphere, Nobel lecture, 12 December 1947, printed p. 81, final three paragraphs]{ref}