2182 kHz: International Maritime Distress and Calling Frequency for Radio telephony.
4340 kHz: NATO Combined Submarine Distress.
8364 kHz: Survival Craft.
121.5 MHz: International Aeronautical Emergency Frequency.
156.8 MHz: International Maritime Distress, Calling and Safety Frequency.
243.0 MHz: NATO Combined Distress and Emergency Frequency.
406.0 MHz: Emergency Position Indicating Locator Beacon (EPIRB).
Note: The 500 kHz International Distress and Calling Frequency for Radio Telephony has been replaced by the Global Maritime Distress and Safety System (GMDSS) since 1999. Accordingly, use of the band has diminished, however, in practice the 500 kHz is still monitored but as of 2010 has ceased to be used as the primary distress calling frequency at sea.
Monitoring of Frequencies
With effect from 1 February 2009, satellite monitoring of ELT (EPIRB) signals transmitted by aircraft or personal locator beacons on frequencies 121.5 MHz and 243 MHz ceased. Such monitoring is now restricted exclusively to the band 406.0 MHz to 406.1 MHz which is generally referred to simply as 406 MHz, as in the list above.