International distress frequency

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An international distress frequency is a radio frequency that is designated for emergency communication by international agreement.

History[edit]

For much of the 20th century, 500 kHz was the primary international distress frequency. Its use has been phased out in favor of the Global Maritime Distress Safety System.

Use of some distress frequencies is permitted for calling other stations to establish contact, whereupon the stations move to another frequency. Such channels are known as distress, safety and calling frequencies.[1]

Satellite processing from all 121.5 or 243 MHz locators has been discontinued. Since February 1, 2009, the U.S. Coast Guard only monitors distress signals from emergency position indicating radio beacons (EPIRBs) that broadcast using digital 406 MHz signals.[2] Digital 406 MHz models became the only ones approved for use in both commercial and recreational watercraft worldwide on January 1, 2007.[3]

Maritime Mobile Service frequencies[edit]

International distress frequencies, currently in use are:

  • 2182 kHz for medium range maritime voice use. The US Coast Guard has said "beginning August 1st, 2013 the Coast Guard would no longer monitor 2182 kHz".[4] Many other MRCCs, for example most in Northern Europe, now only have MF capabilities and no HF.[5]
  • Several HF maritime voice frequencies exist for long-distance distress calls:[6]
    • 4125 kHz
    • 6215 kHz
    • 8291 kHz
    • 12290 kHz
    • 16420 kHz
  • Marine VHF radio Channel 16 (156.8 MHz) for short range maritime use
  • 406 MHz to 406.1 MHz is used by the Cospas-Sarsat international satellite-based search and rescue (SAR) distress alert detection and information distribution system

Digital selective calling frequencies[edit]

Several maritime frequencies are used for digital selective calling (DSC), and they are also monitored for DSC distress signals:[6][7]

  • 2.1875 MHz
  • 4.2075 MHz
  • 6.312 MHz
  • 8.4145 MHz
  • 12.577 MHz
  • 16.8045 MHz
  • 156.525 MHz, Marine VHF radio Channel 70

Aeronautical frequencies[edit]

Search And Rescue frequencies[edit]

  • 123.1 MHz: Aeronautical Auxiliary Frequency (International voice for coordinated SAR operations).
  • 138.78 MHz— U.S. military voice SAR on-the-scene use. This frequency is also used for direction finding (DF).
  • 155.160 MHz
  • 172.5 MHz— U.S. Navy emergency sonobuoy communications and homing use. This frequency is monitored by all U.S. Navy ASW aircraft assigned to a SAR mission.
  • 282.8 MHz— Joint/combined on-the-scene voice and DF frequency used throughout NATO
  • 406 MHz / 406.1 MHz - Cospas-Sarsat international satellite-based search and rescue (SAR) distress alert detection and information distribution system
  • Emergency position-indicating radiobeacon station (EPIRB)
  • Search and rescue transponder (SART)
  • Survival radio

Amateur radio frequencies[edit]

VHF, UHF calling frequencies can also used to make emergency calls[edit]

Band Global Region 1
Europe, Africa
Region 2
The Americas[8]
Region 3
Asia
13 cm
23 cm 1294.500 MHz (U.S.)
33 cm N/A 927.500 MHz (U.S.) N/A
70 cm 446.00 MHz (U.S.)
1.25 m N/A 223.500 MHz (U.S.) N/A
2 m 146.520 MHz (U.S. & Canada)
4 m N/A
6 m 52.525 MHz
10 m 29.600 MHz
12 m RTTY/Packet only

MF and HF frequencies[edit]

Band Global[9][10] Region 1[11]
Europe, Africa
Region 2[12]
The Americas
Region 3[13]
Asia
15 m 21360 kHz
17 m 18160 kHz
20 m 14300 kHz
30 m
40 m n/a 7110 kHz 7060 kHz

7240 kHz 7275 kHz

7110 kHz
60 m n/a
80 m n/a 3760 kHz 3750 kHz

3985 kHz

3600 kHz
  • Emergency/Disaster Relief Interoperation Voice Channels of the amateur radio Global ALE High Frequency Network:[14]
    • 3791.0 kHz USB
    • 7185.5 kHz USB
    • 10145.5 kHz USB
    • 14346.0 kHz USB
    • 18117.5 kHz USB
    • 21432.5 kHz USB
    • 24932.0 kHz USB
    • 28312.5 kHz USB

Other frequencies[edit]

  • Citizens band (CB) radio (not available in all countries)
    • Emergency channels 9 (27.065 MHz AM) and 19 (27.185 MHz AM)
  • GMRS: 462.675 MHz is a UHF mobile distress and road information calling frequency allocated to the General Mobile Radio Service and used throughout Alaska and Canada for emergency communications; formerly called Orange Dot in the 1960s, "GMRS 675" or Channel 6 on mobile radios today. Its bandwidth can vary between 12.5, 25 and 50 kHz, and is also allocated to Ch. 20 on 22-channel FRS/GMRS "blister pack" radios. It can have a repeater input frequency of 467.675 MHz, and a tone squelch of 141.3 Hz.
  • MURS: 151.940 MHz
  • FRS: FRS 3: 462.6125 MHz[15]

See also[edit]

References[edit]

  1. ^ Bartlett, Tim (2006). VHF Handbook. Southampton: The Royal Yachting Association. pp. 28, 31. ISBN 978-1-905104-03-1.
  2. ^ "Logon Form". www.piersystem.com.
  3. ^ "Logon Form". www.piersystem.com.
  4. ^ "USCG: Commercial Fishing Vessel Safety Program - 13th Coast Guard District - Guardians of the Pacific Northwest". www.uscg.mil.
  5. ^ UK Hydrographic Office (2017). Volume 1 (NP281) - Maritime Radio Stations (Parts 1 & 2). UK: UK Hydrographic Office.
  6. ^ a b "HF Distress and Safety Watchkeeping Schedule". U.S. Coast Guard Navigation Center. U.S. Coast Guard. Retrieved Oct 12, 2011.
  7. ^ "Recommendation M.541: Operational procedures for the use of digital selective-calling equipment in the maritime mobile service". International Telecommunications Union. 2015.
  8. ^ "ARRL Band Plans".
  9. ^ "IARU Emergency Telecommunications Guide" (PDF).
  10. ^ "Emergency Center of Activity Frequencies adopted by the IARU Region 1 General Conference 2005" (PDF).
  11. ^ Ulli, DK4VW -. "HF - International Amateur Radio Union - Region 1". iaru-r1.org.
  12. ^ http://www.iaru.org/uploads/1/3/0/7/13073366/r2_band_plan.pdf
  13. ^ http://www.iaru.org/uploads/1/3/0/7/13073366/r3_band_plan.pdf
  14. ^ INC, copyright 2007 HFPACK,. "HFLINK - HF Automatic Link Establishment HF ALE HF Network Ham Radio Amateur Radio HF Emergency Disaster Relief Communications". hflink.com.
  15. ^ "SHTF Survialist Radio Frequency Lists".