Nødfrekvens

Nødfrekvens, or emergency frequency, is a radio frequency designated for distress and safety communications to enable rapid contact and coordination with rescuers and other stations during emergencies. The concept is standardized by international and national authorities to provide a reliable channel that can be used when normal communications fail or are overwhelmed.

In practice, the exact frequency depends on the service and region. Aviation typically relies on a designated distress frequency such as 121.5 MHz for voice calls and older procedures, while modern air‐and space rescue systems increasingly use satellite-based beacons on 406 MHz under the Cospas-Sarsat program. In maritime communications, the distress and safety channel is usually VHF Channel 16, which operates at 156.8 MHz and serves as the primary call channel to establish contact before switching to a working channel. For land mobile and amateur radio users, there are national or regional emergency frequencies that may be used to request immediate assistance if normal channels are unavailable.

Operation and etiquette for nødfrekvens emphasize concise transmission: identify the station, state the nature of distress, describe the location and needed assistance, and provide any relevant details such as numbers or hazards. After initial contact, stations typically communicate on a designated working channel and continue to coordinate with rescue authorities.

The role of nødfrekvens is evolving with advances in digital and satellite systems, but it remains a fundamental element of safety communications, complementary to newer distress networks and beacons.