84 NAUTICAL CHART MANUAL 



RADIOBEACONS (Figs. 1, 24) (M-3, 4, 5) 



Radiobeacons are operated continuously with a series of six radiobeacons sequenced on a 

 single frequency. In the system of time sharing, the six beacons are sequenced to transmit for 

 a period of one minute in consecutive rotation with the exception of marker radiobeacons which 

 operate continuously transmitting a series of }^-second dashes for 13^ seconds, silent Iji seconds. 

 Details relative to radiobeacons will be found in the Light List and U.S. Naval Oceanographic 

 Office Publication No. 117, Radio Navigational Aids. For pohcy governing charting of aero- 

 nautical radiobeacons, see Page 30. 



Radiobeacons are indicated on the charts by a magenta circle 7.1 mm. in diameter. The 

 magenta circle need not be shown adjacent to the standard abbreviation note shown on the 

 charts. 



For charts on the Atlantic Coast with scales from 1:40,000 to 1:1,000,000, and on the 

 Pacific Coast with scales from 1 :40,000 up to the smallest scale charts, excluding Charts 9340, 

 9400, 4000, 9000, the frequency, code signal and operating schedule shall be indicated 

 adjacent to the radiobeacon symbol, thus: 



R Bn 302 & \ 



Continuously (Im on-5m silent) 



In Canada, with the exception of those beacons revised to the above standards, the charac- 

 teristic signal is usually repeated three times and is followed by one or more dash signals. In 

 this case the legend should be charted as foUows: 



R Bn 300 •••— 3 times & — — 

 eOmlOm & 30m-40m 



On charts with scales other than those mentioned above, only the radiobeacon symbol 

 (magenta circle 7.1 mm. in diameter) and the legend R Bn shall be charted. 



Only marine radiobeacons have been calibrated for surface use. Limitations on the use 

 of other radio signals as an aid to marine navigation can be found in the "List of Lights and 

 other Marine Aids," published by the Coast Guard and "Radio Navigational Aids," Naval 

 Oceanographic Ofiice Publication No. 117. 



DISTANCE FINDING STATIONS (Fig. 24) (M-15) 



Sound signals synchronized with radiobeacons shall be indicated on the charts by the ab- 

 breviation "DFS." 



