GMDSS Radio Survey Blog
Emergency Position Indicating Radio Beacons (EPIRBs) are small, portable, battery powered radio transmitters that are both watertight and buoyant and transmit in the 406.0 – 406.1 MHz channel. EPIRBs are carried aboard merchant ships, some private vessels, commercial and military aircraft. They also transmit a distinctive swept audio tone signal on the international aeronautical distress frequencies of 121.5 MHz for homing purposes by search and rescue aircraft. Aircraft at 30 000 feet can detect the audio tone signals at approximately 200 n miles.
