There was plenty of advance warning — back to October of 2000 — when the International Cospas-Sarsat Program, announced at its 25th Council Session held in London, UK of plans to terminate satellite processing of distress signals from 121.5 and 243 MHz emergency beacons on February 1, 2009. And so all mariners, aviators, and individuals using emergency beacons on those frequencies will need to switch to those operating on the newer, more reliable, digital 406 MHz frequency if they want to be detected by satellites.

  The decision to stop satellite processing of 121.5 / 243 MHz signals is due to problems in this frequency band which inundate search and rescue authorities with poor accuracy and numerous false alerts, adversely impacting the effectiveness of lifesaving services.  Although the 406 MHz beacons cost more at the moment, they provide search and rescue agencies with more reliable and complete information to do their job more efficiently and effectively.  The Cospas-Sarsat Program made the decision to terminate 121.5/243 MHz satellite alerting services, in part, in response to guidance from the International Maritime Organization (IMO) and the International Civil Aviation Organization (ICAO). These two agencies of the United Nations are responsible for regulating the safety on international transits of ships and aircraft, respectively, and handling international standards and plans for maritime and aviation search and rescue. More than 180 nations are members of IMO and ICAO.

  NOAA, along with the U.S. Coast Guard, U.S. Air Force, and NASA (the four Federal Agencies who manage, operate, and use the SARSAT system) are strongly advising users of 121.5/243 MHz beacons to make the switch to 406.  Meanwhile, anyone planning to buy a new distress beacon may wish to take the Cospas-Sarsat decision into account.