Originally the German wartime Elektra Sonne, a hyperbolic navigation aid, now obsolete, described technically as a collapsed hyperbolic system. With a range of 1,600 kilometres (1,000 mls.) it required no special equipment beyond a beacon-band radio receiver with a BFO (beat frequency oscillator) facility. Each Consol station transmitted a sequence of 60 dots and dashes which the navigator would count. The moment the dots or dashes changed from one to the other was known as the equisignal and the number of either dots or dashes before the equisignal represented a position line which would be either plotted on a Consol lattice chart or taken from special tables. An observation from two stations would provide a fix. The attraction of the system to many fishermen and yachtsmen on the Atlantic coasts of Europe in the 1950s was to some extent due to the fact that no special equipment was required. A similar system called Consolan, also defunct, was in operation in the USA.
Subjects: Maritime History.