In the vast ocean, vast sky or uninhabited areas, radio communication is the only “lifeline” in times of distress. There are many internationally recognized distress and safety communication frequencies in the VHF (very high frequency) and UHF (ultra-high frequency) bands, which are the “golden channels” for rescue operations.
- Aviation emergency frequency: “First response” for air distress 121.5MHz (AERO-SAR)
Core use: Global aviation emergency frequency, used for aircraft distress calls and search and rescue coordination. Lifeboat radio stations can also use this frequency.
Prohibited interference: No equipment shall cause harmful interference to this frequency band (ITU-R M.690-3 Recommendation). Auxiliary frequency: 123.1MHz is used for collaborative operations between aircraft and ground search and rescue units.
- Maritime distress communication: the “core channel” for maritime rescue
156.8MHz (VHF CH16)
“Global Maritime Distress Channel” : The radiotelephone communication frequency that ships are required to maintain when in distress, and aircraft can also use it for safety communications.
Related functions :
156.525MHz (CH70): Dedicated to digital selective calling (DSC), triggering rapid positioning.
156.65MHz (CH13): Ship-to-ship navigation safety communication (such as collision avoidance coordination).
AIS-SART rescue signal
161.975MHz (AIS1) and 162.025MHz (AIS2): Automatic Identification System (AIS) search and rescue beacon frequencies, transmitting the position of distressed ships to improve search and rescue efficiency (ITU-R M.1371 Recommendation).
- Satellite and AIS technology: “Skynet rescue” with full coverage
Satellite Emergency Position Indicating Beacon (EPIRB)
406-406.1MHz: Dedicated to satellite EPIRB, the signal is relayed to the ground station via satellite, covering the world.
1530-1545,1614.4-1646.5, 2483.59-2499.91MHz frequency bands : Dedicated to satellite maritime mobile service distress communications, GMDSS (Global Maritime Distress and Safety System) priority protection.
Radar Search and Rescue Beacon (SART)
9200-9500MHz: Radar transponder frequency band, distressed ships release signals to facilitate rescue radar detection.
What are the frequencies for distress and safety communications in the VHF and UHF bands?
1)*121.5 Mhz (AERO-SAR)
The 121.5 MHz aeronautical emergency frequency is used by stations in the aeronautical mobile service using frequencies in the band 117.975 MHz to 137 MHz for radiotelephony for distress and emergency purposes. This frequency may also be used by lifeboat stations for these purposes. The use of the frequency 121.5 MHz by emergency position-indicating radio beacons shall be in accordance with Recommendation ITU-R M.690-3.
2)123.1Mhz (AERO-SAR)
The 123.1 MHz frequency is an auxiliary frequency to the 121.5 MHz aeronautical emergency frequency and is used by aeronautical mobile service stations and other mobile and land stations engaged in coordinated search and rescue operations.
3) 156.3 MHz (VHF-CH06)
The 156.3 MHz frequency can be used for communications between ship stations and aircraft stations engaged in coordinated search and rescue operations, and can also be used by aircraft stations to communicate with ship stations for other safety purposes.
4) *156.525 Mhz (VHF-CH70)
The frequency 156.525 MHz is used in the maritime mobile service for distress and safety calls using digital selective calling.
5) 156.650 MHz (VHF-CH13)
The 156.650 MHz frequency is used for ship-to-ship communications related to navigation safety.
6) *156.8 Mhz (VHF-CH16)
The 156.8 MHz frequency is used for distress and safety communications by radiotelephone. In addition, the 156.8 MHz frequency may be used by aircraft stations for communications for safety purposes only.
7）*161.975 Mhz (AIS-SART VHF CH AIS 1 )
AIS 1 is used for AIS Search and Rescue Transmitter (AIS-SART) in search and rescue operations.
8）*162.025 Mhz ( AIS-SART VHF CH AIS 2 )
AIS 2 is used for AIS Search and Rescue Transmitter (AIS-SART) in search and rescue operations.
9) *406-406.1 Mhz ( 406-EPIRB )
This frequency band is dedicated to satellite emergency position-indicating radio beacons in the ground-to-air direction.
10) 1530-1544 Mhz ( SAT-COM )
In addition to routine non-safety communications, the 1530-1544 MHz band is used for distress and safety communications in the air-to-Earth direction of the maritime mobile satellite service. GMDSS distress, urgency and safety communications have priority in this band.
11) *1544-1545 Mhz (D&S-OPS)
The use of the 1544-1545 MHz band (space-to-Earth) is limited to distress and safety operations, including: satellite feeder links required to relay transmissions from satellite emergency position-indicating radio beacons to earth stations, and narrowband (space-to-Earth) links to relay transmissions from space stations to mobile stations.
12) 1614.4225- 1618.725 Mhz or 1616.3-1620.38 MHz
( SAT-COM )
In addition to conventional non-safety purposes, the band 1614.4225-1618.725 MHz or 1616.3-1620.38 MHz (Earth-to-air) is used for distress and safety purposes in the Earth-to-air direction of the maritime mobile-satellite service. GMDSS distress, urgency and safety communications have priority in this band over non-safety communications within the same satellite network.
13) 1621.35-1626.5 Mhz ( SAT-COM )
In addition to conventional non-safety purposes, the 1621.35-1626.5 MHz band is used for distress and safety purposes in the Earth-to-air and air-to-Earth directions of the maritime mobile-satellite service. GMDSS distress, urgency and safety communications have priority in this band over non-safety communications within the same satellite system.
14）1626.5-1645.5 Mhz ( SAT-COM )
In addition to routine non-safety communications, the 1626.5-1645.5 MHz band is used for distress and safety communications in the Earth-to-air direction of the maritime mobile satellite service. GMDSS distress, emergency and safety communications have priority in this band.
15）1645.5-1646.5 Mhz ( SAT-COM )
The use of the 1645.5-1646.5 MHz band by the mobile satellite (Earth-to-space) service and for inter-satellite links is limited to distress and safety communications.
16) 2483.59-2499.91 Mhz ( SAT-COM )
In addition to conventional non-safety purposes, the 2483.59-2499.91 MHz band is used for distress and safety purposes in the air-to-Earth direction of the maritime mobile-satellite service. GMDSS distress, urgency and safety communications have priority over non-safety communications within the same satellite network in this band.
17) 9 200-9 500 Mhz ( SARTS )
This frequency band is used by radar transponders for search and rescue purposes.
Description:
AERO-SAR These aeronautical carrier frequencies may be used for distress and safety purposes by mobile stations engaged in coordinated search and rescue operations.
D&S-OPS The use of these frequency bands is limited to distress and safety operations of satellite emergency position-indicating radio beacons (EPIRBs).
SAT-COM These frequency bands may be used for distress and safety purposes in the maritime mobile-satellite service.
VHF-CH# These VHF frequencies are used for distress and safety purposes. The channel number (CH#) refers to a VHF channel.
AIS These frequencies are used by the Automatic Identification System (AIS) which shall operate in accordance with the most recent version of Recommendation ITU-R M.1371.
- Any emission, other than that specified in these Regulations, which could cause harmful interference to distress, alert, urgency or safety communications, is prohibited on the frequencies indicated by an asterisk (*).
