New EPIRB processing practices to reduce false distress alerts

The following is the text of a feature story submitted by the U.S. Coast Guard:


Story by Petty Officer 3rd Class Melissa Hauck

(ALAMEDA, Calif.) — The Coast Guard and other emergency personnel who respond to distress calls will soon see an improvement in their ability to locate people during search and rescue cases.

This improvement centers around an emergency position indicating radio beacon (EPIRB), a device that when activated can act as a virtual lifeline from people in distress to rescue crews by sending out a transmitted signal via air, sea or land.

On Feb.1, 2009 Cospas-Sarsat, an international satellite-based search and rescue (SAR) system established by the U.S., Canada, Russia and France will cease satellite processing of 121.5/243 MHz analog EPIRBs and will begin processing only the 406 MHz digital radio beacon signals, making it illegal to use the obsolete 121.5/243 MHz beacons.

The newest 406 MHz beacons incorporate global positioning system (GPS) receivers that transmit highly accurate positions of distress almost instantly to SAR agencies via the Geostationary Earth Orbit Local User Terminals (GEOSAR) satellites.

The digital frequency has been designated internationally for use only for distress. Other communications and interference, such as on 121.5 MHz analog signals, is not allowed.

The change is expected to result in a substantial reduction in wasted SAR resources on false alerts while simultaneously increasing the responsiveness of the system for real distress cases.

“The 121.5 MHz analog beacons produce a high incidence of false alarms and a host of other limitations that include poor signal strength, search areas that can be as large as 12 to 15 miles in radius and unreliability,” said Petty Officer 2nd Class Craig Mercier, an operations specialist stationed at the District 11 command center on Coast Guard Island here.

“The distress signals from the 406 MHz beacon are much more accurate than the analog beacon. Each digital beacon has a unique ID encoded within its signal that can quickly confirm that the distress is real, who they are looking for and where they should look, which will ultimately save lives,” he said.

When a 406 MHz signal is received, SAR authorities can retrieve information from law-required registration data that includes beacon owner contact information, emergency contact information and identifying characteristics of the vessel.

“Digital EPIRBS also provide position accuracy that narrows the vessel’s position to less than two miles in radius and decreases the amount of time SAR teams must search. This results in quicker response times, and is a major advantage over the 121.5 MHz beacons,” he said.

The decision to stop satellite processing of 121.5 / 243 MHz signals was announced by Cospas-Sarsat nearly two years ago stating problems in the frequency band which overwhelm search and rescue authorities with poor accuracy and numerous false alerts, negatively impacting the effectiveness of lifesaving services.

The Coast Guard strongly recommends mariners obtain the new 406 MHz EBIRB and file a float plan with a friend or family member on land, with an approximate time of return and location prior to getting underway. A float plan template can be found at

EPIRB owners can register their equipment in the U.S. 406 MHz Beacon Registration Database at: or by calling 1-888-212-SAVE. Beacon registration is required to be updated with accurate information every two years or when emergency contact or other information changes.

For more information on EPIRBS and the Cospas-Sarsat program visit

By Professional Mariner Staff