E zone

E zone

[′ē ‚zōn]
(communications)
One of the three zones into which the earth is divided to show the variations of the F2 layer in respect to longitude when one is making frequency predictions; it roughly covers Asia, Australia, the Philippines, and Japan.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.