The U.S. Coast Guard recently announced that on February 1, 2009, the international CosPas-Sarsat System will terminate the satellite processing of distress signals received from 121.5 and 243 MHz emergency beacons. Replacing them will be the 406 MHz beacons that are already in use, and one proven to be much more reliable and effective according to USCG.
In the marine realm, the CosPas-Sarsat satellite system responds to alerts received from EPIRBS carried on vessels, as well as personal locator beacons (PLBs) used by individuals. In conjunction with the switch, the USCG is encouraging mariners to switch to emergency beacons operating at 406 MHz.
The decision to terminate the use of the 121.5 and 243 MHz for satellite distress alerting was based, in part, on the guidance received from the IMO and the International Civil Aviation Organization (ICAO), both which are UN agencies responsible for regulating safety onboard ship and aircraft on international transit.
A major factor influencing the decision to terminate the use of the 121.5 and 243 MHz for satellite distress alerting is the false alerts associated with these frequencies that inundate search and rescue authorities, false alerts which obviously compromise effectiveness in the case of a real emergency. While USCG points
out that the new 406 MHz units are more expensive, it similarly notes that the information provided is more reliable and complete, allowing them to complete their jobs more efficiently and effectively.