Propagation characteristics of microwave optical links

The performance of point-to-point microwave links is affected considerably by the nature of the terrain which the links traverse and the variable refractivity of the lower atmosphere due to changes in the local meteorological conditions. While a great deal of information is available on these two factors, it is in many cases difficult to predict with any degree of assurance the reliability to be expected on a microwave link installed on a given path. It is usually advisable to mke an experimental survey of propagation char"acteristics and siting factors involved on such a path. This paper describes the reslllts of an experimental propagation survey which was made on two paths in the San Frmcisco Bay (USA) area.