Mobile v.h.f. and u.h.f. radio systems in the UK

Mobile radio systems, operating in the v.h.f. and u.h.f. bands, are widely used in the United Kingdom for short-range land, maritime and aeronautical services. In tracing the growth of these services the preponderance of land-mobile units is evident, and the review concentrates on land-mobile aspects, referring to the others mainly when differences in equipment or practice are significant. Developments in equipment and systems are reviewed, and selected units and installations are briefly described. The market for new and replacement equipment is estimated, and possible savings through the use of mobile radio are discussed. Other systems such as paging, which use the same frequency bands or techniques as mobile radio, are enumerated, and their operation and merits examined. One Section is devoted to the design of selected sections of equipment and another to the estimation of range. Typical figures for land-mobile systems are tabulated. The ever present problems of frequency selection, interference and noise are reviewed. The two main, and several proposed, systems of modulation are compared, and their future possibilities discussed. Final Sections examine reliability and testing, possible future developments and problems. Some possible lines of progress are deduced. A carefully selected, rather than a comprehensive, list of references is given.