Chuck Husick: Techno-Talk, May 2002 BoatUS Magazine - Updated June 2009

NAVTEX Receivers

It's a safe bet that most of the readers of this column believe they already have more than enough radio receivers on their boats, including a VHF transceiver, a hand-held VHF, an entertainment radio, a pair of FRS radios and a cell phone. Some boats also carry a CB radio. Larger boats that venture offshore  equipped with satellite receivers can access a great deal of timely and valuable information, however a NAVTEX receiver will provide up-to-date information of the type included in local notices to mariners. With all those radios on board, why would you want another one? The information that follows might make you want to add just one more to your equipment list.

The new radio will be markedly different from any you now have. It can listen to only one fixed frequency, 518 kHz, so there is no tuning knob. The signals it receives are digital. It has no loudspeaker and the only sound it can emit is a beep. Since it can't speak you don't have to listen to it but it will remember everything it hears and will tell you all it knows whenever you wish. It will use its beep to call you when it receives a message warning of a problem with navaids, severe weather or search and rescue activities.

Your boat's new radio is called a NAVTEX (for NAVigational TeleX) receiver and is a part of the Global Marine Distress and Safety System (GMDSS) equipment required to be on board all large ships and most passenger liners. If your boating activities include either offshore or near-shore waters you should consider adding this radio to your electronics suite. Don't buy one if you run your boat on lakes, rivers or other inland waters. You won't find anything to listen to.

The new radio will bring you up to the minute information about navigation aids, telling you that the range light you rely on when returning to port is dim or that a hazard buoy has been placed in the channel in which you will be navigating an hour from now. In many ways the information from this radio will parallel the content of the weekly Notice to Mariners, except that instead of reporting past events it will tell you what has just happened or is about to happen.

In addition to the Notice to Mariners content, the radio will provide weather forecasts and warnings of hazardous weather at distances well beyond the coverage of the NOAA VHF/FM stations. Received messages will include search and rescue activities and notice of areas where activities that may be hazardous to navigation are being conducted, information that may be of particular interest in this period of concern for terrorist activities.

NAVTEX receivers are typically small, about 9 by 5 by 3 inches and use a miserly amount of electrical power, about 1/4 amp. The NAVTEX receivers used on SOLAS convention ships decode the messages they receive and print them on a strip of paper. The NAVTEX receiver you may want decodes the messages and stores them in memory. Received message labels are displayed on the radio's LCD panel and can be selected and read using the keypad controls. If you wish, you can connect the receiver to a computer and store endless amounts of information.

NAVTEX messages are transmitted in digital form and are error checked upon receipt. The receiver will reject messages found to have more than a preset error percentage. All messages are stored for display when desired, eliminating the need to listen to the occasionally difficult to understand synthesized voice on the HF/SSB or VHF/FM weather broadcasts.

The source of transmissions to your NAVTEX radio are located along the coastline of virtually all countries and can be received up to about 200 miles from shore during daylight and about twice as far at night. The transmitters take turns transmitting on the single common 518 kHz frequency. The messages are identified by up to 13 letter codes.

The most important codes dealing with navigational warnings, weather, and search and rescue are A, B and D. Any NAVTEX receiver you may buy will include a full explanation of how to program the set so that you will always be alerted to the information you need for navigation safety. Should your voyages take you to foreign countries where English is not the native tongue you will particularly value the fact that all NAVTEX messages worldwide are transmitted in English in addition to any other language.