EPIRBS — How To Be Heard

In Ocean Navigators’ eNewsletter EPIRBs (emergency position indicating radio
beacons) are explained. A very interesting read (not online yet), and a necessary one if you’re thinking of buying/using one. It stresses the importance of registering your beacon for verificaton purposes. More then 90% of calls are false, and without any verification there is little hope you will be rescued.
“Let�s look at how 406 and 121 EPIRB signals are handled. A 406-MHz signal is picked up by a worldwide network of orbiting satellites generally within a couple minutes of activation. The 406 transmits the electronic serial number of your EPIRB. A GPS EPIRB adds GPS position of the unit to the transmission. Without GPS information, additional satellite passes are necessary to triangulate the location of the distress signal.
Think of it this way: The 121 says, “HELP.” The 406 EPIRB says, “This is the vessel Serenity, and I need HELP.” The 406 GPS EPIRB says, “This is the vessel Serenity; I�m at 40 degrees 50.223 minutes, 61 degrees 19.456 minutes, and I need HELP.” Position can be determined without the GPS information, but it may take 30 minutes or so for 406 and several hours or more for 121.”