Part of the international Global Maritime Distress and Safety System (GMDSS), NAVTEX is a radio broadcasting system, transmitting at 518 kHz in the medium frequency band, for textual weather information distribution. It is intended to service vessels within 200 miles of shore, the 200 mile limit being widely used in navigation and seafaring, as in the Exclusive Economic Zone or Air Defense Identification Zone.
The United Kingdom Hydrographic Office is coordinator for the the International Hydrographic Organization (IHO) Worldwide Navigational Warning Service (WWNWS). In addition, UKHO is the NAVAREA I (NE Atlantic) Co-ordinator for the International Maritime Organization (IMO) and the United Kingdom National Co-ordinator for issuing coastal navigational warnings.Cite error: Invalid
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For U.S. waters, the United States Coast Guard transmits NAVTEX information, in coordination with other government agencies, such as the National Weather Service, for inland waters. Other services include safety information in other frequency bands, as well as radiofacsimile weather information.