MARINE RADIOBEACON SYSTEM 



A Medium Range Aid to Navigation System 



INTRODUCTION 



Every mariner and every person who travels upon the sea recognizes radio 

 for its many contributions to increased safety. The earliest application of 

 radio to safety at sea was communication between ship and shore. This has 

 been the means of saving the crews and passengers of many foundering ves- 

 sels which otherwise would have been listed simply as "missing." Incidental 

 to this came the broadcasting over the whole sea area of accurate time and 

 weather warnings, giving the mariner a frequent check on his chronometer 

 and on weather conditions. In 1921 the first successful radiobeacons were 

 established in the approaches to New York. The system of navigation from 

 radiobeacons, by means of bearings taken from direction finding equipment 

 on shipboard, has become well established as a most important method of 

 enabling vessels to check their positions. 



Direction-finder navigation is not restricted to bearings on regularly estab- 

 lished radiobeacon stations, as the same navigation principles apply to bear- 

 ings on any fixed radio station whose position is known, or on any mobile 

 radio station, as another ship whose position has a significance in the naviga- 

 tion of the observing vessel. 



Figure 2-1. — Cape Cod Light Station, Massachusetts. Established 1798. Kebuilt 1857. 

 Top of lantern 66 feet above ground. Light 183 feet above water. Foundation : rubble 

 stone masonry. Signals : First order electric apparatus. Flashing white every 5 seconds. 

 Flash 0.2 second, eclipse 4.8 seconds. 13,000 candlepower. High-power class A radio- 

 beacon. Special antenna in background. Fog signal : horn, diaphragm, electric ; blast 

 3 seconds, silent 12 seconds. 



MARINE RADIOBEACON SYSTEM OF THE UNITED STATES 



There were 186 radiobeacons (fig. 2-2) in operation on the coasts of this 

 country on April 1, 1949, constituting a large system of aids to navigation. 

 This system, operated by the United States Coast Guard, is important among 



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