Today 6/30/17 was a good day for Sporadic E on 28 and 50 Mhz. I worked several stations on 50 Mhz. My 10 meter beacon was heard in several parts of the USA. ..... Jack WB9OTX
Sporadic E or Es is an unusual form of radio propagation using characteristics of the Earth's ionosphere. Whereas most forms of skywave propagation use the normal and cyclic ionization properties of the ionosphere's F region to refract (or "bend") radio signals back toward the Earth's surface, sporadic E propagation bounces signals off smaller "clouds" of unusually ionized atmospheric gas in the lower E region (located at altitudes of approx. 90 to 160 km). This occasionally allows for long-distance communication at VHF frequencies not usually well-suited to such communication.
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From wikipedia.org