What is a sporadic-E condition?

Sporadic-E refers to temporary, unpredictable patches of highly dense ionization that form in the E region of the ionosphere, typically about 90 to 120 kilometers above the Earth. These localized clouds of electrons act like radio mirrors for higher frequencies. Unlike standard F-layer propagation, Sporadic-E does not heavily depend on the 11-year sunspot cycle and occurs most frequently during the summer months. Other options are incorrect because ducting happens much lower in the troposphere, and Sporadic-E causes sudden increases in signal range rather than decreases.