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A Review Of High Frequency Radio Wave Absorption, David Alan Smith Dec 2016

A Review Of High Frequency Radio Wave Absorption, David Alan Smith

David Smith

Although the technology dates back nearly to Marconi and his wireless telegraph, the high-frequency (HF) radio spectrum continues to be a useful communications medium.  Since long-distance HF propagation depends on the ionosphere, HF propagation is subject to variations in ionospheric characteristics.  Chief among these characteristics is the density of free electrons.  The sun provides the energy required to ionize neutral atmospheric constituents.  Hence, the production and loss of free electrons is not constant.  Day/night variations as well as the ebb and flow of the 11-year solar cycle cause changes in the density of free electrons.  In addition, space weather ...