Long-Range Communication Trends

The long-range communication problem is briefly reviewed with respect to the problems brought about by the use of inosphere transmission. A description is given of the multipath transmission involved and the various types of fading which result. Methods of reducing the different fading effects are discussed. These include the use of diversity reception and exalted-carrier detection. The different types of modulation are considered with respect to their application to ionosphere transmission. The recent trend away from amplitude-actuated modulations towards angle and single-sideband modulation is considered.