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OCEAN ELECTRONIC NAVIGATIONAL AIDS 



the system of lights, buoys, and other navigational aids, the maintenance 

 of which is a principal function of the Coast Guard. Radio-beacons add 

 greatly to the completeness of aids to navigation systems and fill an important 

 gap in previously available facilities. The United States maintains far more 

 radiobeacons than any other one country. 



Because of the many factors affecting navigation it is somewhat difficult, 

 from an analysis of statistics, to show the effect of radiobeacon navigation 

 in the way of increasing safety, but the following figures are of interest. On 

 the Great Lakes the benefits from radiobeacons were remarkably effective 

 during 1927-30. In this 4-year period there were 31 strandings in a group 

 of 470 vessels, or 1 for each 15 vessels. For the years 1923-26, before the 

 advent of radiobeacons, there were 76 strandings in a comparable group of 

 572 vessels, or 1 stranding for each 7.5 vessels. Shipping interests state that 

 the influence of radiobeacon navigation was an important factor in the 

 reduction thus shown. 



Further developments in equipment and in methods of use for radiobeacons 

 are always under consideration for the improvement and development of the 

 radiobeacon system. 



RADIOBEACON NAVIGATION 



Radiobeacons are radio stations installed at lighthouses, on lightships, or 

 at other points shown on the charts, for the sending out in all directions of 

 radio signals, for the purpose of guiding marine navigation. Radio direction 

 finders are special radio receivers with rotating coil antennas capable of 

 receiving radio signals. 



RADIOBEACON STATIONS 



PANAMA PUERTO RICO 



Figure 2-2. — The Marine Radiobeacon System of the United States, 1949. 



When first introduced, these installations were called radio fog signals 

 or wireless fog signals because they were originally planned for use in fog; 

 but they have developed, as will be described, into valuable aids in either 

 fog or clear weather. Therefore, the restrictive name, "radio fog signal," 

 was considered inappropriate. 



In this country, the direction finding equipment on shipboard nearly always 

 is installed in such a way and the transmitted characteristic signal is such 

 that the navigator himself can conveniently take distinct and easy-to-recog- 

 nize radio bearings. The general problems and practice of navigation are 

 then the same when using radio bearings as they are with visual bearings on 

 lighthouses or other known objects. The practical differences between radio 

 and sight bearings are not differences in principle, but in the availability of 

 the former at much greater distances and under all conditions of visibilty 

 or fog. The radiobeacon is located at a definite point shown on the chart. 



