Abstract
This thesis covers the application of fade counter measure techniques to satellite links using small terminals in the 20/30 GHz band. The case for using the 20/30 GHz band for very small aperture terminal (VSAT) networks is presented together with applications proposed for VSAT networks. A study of the propagation impairments that affect these networks is presented and the propagation environment is determined with particular reference to the problem and severity of rain fading. Relevant equations are presented allowing the calculation of link budgets and performance for VSAT networks operating via a 20/30 GHz satellite transponder. The various methods that may be employed to detect and overcome the high attenuation levels found at 20/30 GHz are presented. Candidate fade counter measure (FCM) schemes, fade detection mechanisms and control methods are discussed, together with their applicability to VSAT networks and their expected performance. The design of the prototype 20/30 GHz VSAT Earth station developed is presented, together with performance simulations, backed up by measurements, made on the prototype. The application and performance of fade counter measure schemes and fade detection methods is determined by computer simulation. Finally recommendations are made for a complete fade counter measure system applicable to a 20/30 GHz VSAT system.