Abstract :
A comprehensive review is made of published work on the theory of beyond-horizon propagation of radio waves by means of oblique scattering from randomly-distributed irregularities of refractive index in the troposphere. A scattering theory is formulated which attempts to take as accurate account as possible of all effects likely to be important in practice, consisting of some new results combined with the best features of existing theories. Application of this theory to a Variety of experimental results yields generally good agreement. Possible causes of some discrepancies, and the likely relative importance of scattering and certain other long-distance propagation mechanisms, are discussed.