Navtex, simple and universal
What Navtex?
The Navtex (Navigational Telex) is an official international system developed in the area of GMDSS, for sailing professionals. The receivers have been developed for leisure craft. They are simple to use and once programmed, will receive bulletins and keep them stored in the memory.
Two types of receptors are proposed: autonomous with LCD screen for reading messages and without screen with a PC output, which connects via a USB port to a computer.
Two types of receptors are proposed: autonomous with LCD screen for reading messages and without screen with a PC output, which connects via a USB port to a computer.
La France possède deux émetteurs (Ouessant au large de Brest et La Garde près de Toulon) qui émettent des messages en français.
Navtex: how does it work?
All transmitters operate on a single frequency, 518 kHz (with a second frequency of 490 kHz to issue national language.) In order to avoid interference between stations in the same area, the diffusion of messages is on specific time slots (every 4 hours) except for BMS. In practice, each service area, called NAVAREA, is divided into geographic area and assigned a letter. For example, the transmitter of la Garde, near Toulon, is located in NAVAREA III and has the identification letter W. Two solutions are possible: set all zones from A to Z or select the ones you wish to receive. Receiving numerous messages sent from different transmitters is not a problem, as they are offset by time. The second programme relates to the content of the messages. As for the stations, each message type is assigned a letter, A to Z. One may, by programming the receiver, select the type of messages desired to receive. For obvious safety reasons, it is not possible to deprogramme certain messages:
mariners bulletins (letter A,) storm warnings (B,) and also search and rescue (D.) Other messages that may be useful in the pleasure craft are K in case of GPS malfunction and E, weather forecasts.
mariners bulletins (letter A,) storm warnings (B,) and also search and rescue (D.) Other messages that may be useful in the pleasure craft are K in case of GPS malfunction and E, weather forecasts.
And the other systems?
Parallel to the Navtex system, we find receivers for receiving weather from the National Agency Germany (DWD). This radio transmits 24 hours a day, sending weather forecasts up to five days in advance for the Mediterranean and two days for the Atlantic. The Weatherman is a receiver that can receive and display the bulletins issued. It combines a HF receiver with software capable of automatically decrypting radio telex signals (RTTY.) The bulletins are in English and free (like those of Navtex). Covering the entire Mediterranean, we recommend it for those who sail in these waters.