NAVTEX
NAVTEX, sometimes styled Navtex or NavTex, is an international automated medium frequency direct-printing service for the delivery of navigational and meteorological warnings and forecasts, as well as urgent maritime safety information to ships. It was developed to provide a low-cost, simple, and automated means of receiving this information aboard ships at sea within approximately 370 km (200 nautical miles) offshore. NAVTEX is a component of the International Maritime Organization/International Hydrographic Organization Worldwide Navigation Warning Service (WWNWS) and a major element of the Global Maritime Distress Safety System (GMDSS) . It is mandatory to be carried by all SOLAS approved vessels.
NAVTEX uses binary frequency-shift keying (BFSK) at 100 bit/s and a 170 Hz frequency shift to transmit messages, and it is transmitted using narrow-band direct printing 7-unit forward error correcting (FEC or Mode B) transmission. The messages contain weather forecasts and are transmitted using an abbreviated format similar to the shipping forecast. The area covered by NAVTEX can extend as far as 400 nautical miles from the broadcast station.
In the United States, NAVTEX is broadcast from Coast Guard facilities in various locations, providing reasonably continuous coverage along the east, west, and Gulf coasts, as well as the areas around Kodiak, Alaska; Guam; and Puerto Rico. The U.S. has no coverage in the Great Lakes, though coverage of much of the Lakes is provided by the Canadian Coast Guard.
In summary, NAVTEX is a crucial system for providing maritime safety information to ships worldwide, and it plays a significant role in ensuring the safety of vessels at sea.
