| 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. |
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