From the USCG Internet Notice,



The USCG and NOAA have issued a notice that 121.5 and 243 MHz emergency beacons will no longer be monitored by satellite after February 1, 2009. This is an international agreement that 406 will be the only recognized satellite emergency signal.

NOTE – – Pilots are reminded and encouraged to monitor 121.5 MHz from their cockpit to listen for other aircraft that may be in distress.

406 EPIRB Frequencies will continue as the primary satellite rescue frequency. Please ensure that you are indeed using a 406 EPIRB (Emergency Position-Indicating Radio Beacons) or PLB (Personal Locator Beacons).

Go2marine only carries 406.037 MHz, EPIRBs and PLBs from recognized manufactures such as ACR, Mcmurdo and Spot, that are approved by COSPAS-SARSAT, R&TTE, or the FCC. Go2marine also sells EPIRBs that are certified to pass the country of origin for any international vessel.


COSPAS-SARSAT rescue information

Number of Persons Rescued in 2009 (As of January 15) in the United States:  6
Rescues at sea:  3 people rescued in 2 incidents
Aviation rescues:  1 person rescued in 1 incident
PLB rescues:  2 people rescued in 2 incidents

Number of Persons Rescued in 2008 in the United States: 283

Rescues at sea:  203 people rescued in 65 incidents
Aviation rescues:  12 people rescued in 7 incidents
PLB rescues:  68 people rescued in 35 incidents

United States Number of Persons Rescued – 6,045 People Rescued  (since 1982)

Worldwide Number of Persons Rescued – Over 24,500+ People Rescued  (since 1982)

406 MHz EPIRBs
The 406 MHz EPIRB was designed to operate with satellites. The signal frequency (406 MHz) has been designated internationally for use only for distress. Other communications and interference, such as on 121.5 MHz, is not allowed on this frequency. Its signal allows a satellite local user terminal to accurately locate the EPIRB (much more accurately — 2 to 5 km vice 25 km — than 121.5/243 MHz devices), and identify the vessel (the signal is encoded with the vessel’s identity) anywhere in the world (there is no range limitation). These devices are detectable not only by COSPAS-SARSAT satellites which are polar orbiting, but also by geostationary GOES weather satellites. EPIRBs detected by the GEOSTAR system, consisting of GOES and other geostationary satellites, send rescue authorities an instant alert, but without location information unless the EPIRB is equipped with an integral GPS receiver.  EPIRBs detected by COSPAS-SARSAT (e.g. TIROS N) satellites provide rescue authorities location of distress, but location and sometimes alerting may be delayed as much as an hour or two. These EPIRBs also include a 121.5 MHz homing signal, allowing aircraft and rescue craft to quickly find the vessel in distress. These are the only type of EPIRB which must be certified by Coast Guard approved independent laboratories before they can be sold in the United States.

A new type of 406 MHz EPIRB, having an integral GPS navigation receiver, became available in 1998.  This EPIRB will send accurate location as well as identification information to rescue authorities immediately upon activation through both geostationary (GEOSAR) and polar orbiting satellites.  These types of EPIRB are the best you can buy.

406 MHz emergency locating transmitters (ELTs) for aircraft are currently available. 406 MHz personnel locating beacons (PLBs) are available.

The Coast Guard recommends you purchase a 406 MHz EPIRB, preferably one with an integral GPS navigation receiver. A Cat I EPIRB should be purchased if it can be installed properly.

406 MHz GEOSAR System
The major advantage of the 406 MHz low earth orbit system is the provision of global Earth coverage using a limited number of polar-orbiting satellite.  Coverage is not continuous, however, and it may take up to a couple of hours for an EPIRB alert to be received.  To overcome this limitation, COSPAS-SARSAT has 406 MHz EPIRB repeaters aboard three geostationary satellites, plus one spare: GOES-W, at 135 deg W; GOES-E, at 75 deg W; INSAT-2A, at 74 deg E; and INSAT-2B (in-orbit spare), at 93.5 deg E.  Ground stations capable of receiving 406 MHz.  Except for areas between the United Kingdom and Norway, south of the east coast of Australia, and the area surrounding the Sea of Okhotsk near Russia, as well as polar areas, GEOSAR provides continuous global coverage of distress alerts from 406 MHz EPIRBs.

Note that GEOSAR cannot detect 121.5 MHz alerts, nor can it route unregistered 406 MHz alerts to a rescue authority.  GEOSAR cannot calculate the location of any alert it receives, unless the beacon has an integral GPS receiver.

COSPAS-SARSAT is an international satellite-based search and rescue system established by the U.S., Russia, Canada and France to locate emergency radio beacons transmitting on the frequencies 121.5, 243 and 406 MHZ.

Space System for Search of Distress Vessels (a Russian acronym)
Search and Rescue Satellite-Aided Tracking