Propagation Impairments: Chapter 4

4.1 INTRODUCTION: The effects of the atmosphere on the propagation of radio energy at microwave frequencies has been intensively studied for many years. Rather than attempting to survey the extensive body of published literature, we shall provide an elementary description of propagation in an ideal atmosphere to provide a basis for explaining the more significant phenomena that impair the performance of digital radios on line-of-sight paths. References to the literature and to the texts of CCIR Study groups 5 and 9 are provided for the reader interested in obtaining more detail.