SARSAT Says Goodbye to 121.5 and 243 MHz Frequency Emergency Beacons

by OldSailor on January 31, 2009


goodbye_121.5mhzToday is the last day, to say goodbye to analog 121.5 and 243 MHz frequencies emergency beacons.

Starting from February 01, NOAA (National Oceanic and Atmospheric Administration) satellites will only receive signals (digital) from the new 406 MHz frequency emergency beacons (ELTs for aviation use, EPIRBs for  maritime use and PLBs for personal use). The older emergency beacons, operating on the 121.5 and 243 MHz frequencies are now phased out and will no longer be detected by  SARSAT.

SARSAT(Search and Rescue Satellite-Aided Tracking) system is operational since 1982 and was developed jointly by the United States, Canada, and France. In the United States, the SARSAT system was developed by NASA (National Aeronautics and Space Administration). Once the system was functional, its operation was handed over to NOAA.

NOAA’s polar-orbiting and geostationary satellites, along with Russia’s Cospas spacecraft, are part of the international Search and Rescue Satellite Aided Tracking system, called COSPAS-SARSAT.

NOAA has provided advance notice of the switchover since 2000.

Here is a comparison, highlighting the advantages of 406 MHz frequency emergency beacons.

Parameters Beacon 121.5 MHz Beacon 406 MHz
Beacon Identification None Unique ID Number
Location Accuracy 12 miles 2 miles
Coverage Local Global
Signal Power 0.1 Watt 5 Watts
Signal Type Analog Digital
Alert Time (minimum) 2 hours Instantaneous
Doppler Location Two Passes Single Pass
GPS Location None 100 metres Accuracy

Here is a self explanatory overview of COSPAS-SARSAT from NOAA


To read more, log on to NOAA – SARSAT.

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