The Decca Navigator System was very unusual among radio-navigation systems in that the entire system was championed and marketed by a commercial company. How it came about was also unusual – it was neither the product of market research nor a military specification. It was a solution to one of the major problems of the 1930s facing those who attempted to use radio methods for the location of vehicles, that of measuring extremely small time intervals. The problem was eventually solved by pulse methods (radar), which were kept very secret at the time, but Decca offered an alternative particularly suited to marine navigation because of its use of low frequencies. No matter how good a technical solution, many systems fail if they are not actively supported by proper marketing and in this Decca Navigator was fortunate to have the backing of a major British company, the Decca Record Company. This paper describes the inception, wartime trials and eventual acceptance into general marine use of Decca Navigator. Some previously unpublished historical material from the company archives is included.
