USCG - Know your high seas comms equipment and how to use them

United States Coast Guard Headquarters
Inspections and Compliance Directorate
Washington, DC
August 3, 2017

Safety Alert 08-17

Know your high seas comms equipment and how to use them.
You just might save your own life when in trouble offshore!

Recent inquiries by Coast Guard Marine Inspectors indicate that a large number of vessel operators and ship masters continue to rely on outdated high seas communications frequencies when communicating with the United States Coast Guard. This Safety Alert reminds all mariners of the appropriate use of Single Side Band High Frequency (SSB-HF) radios when attempting to contact the Coast Guard outside the normal range of Very High Frequency-Frequency Modulation (VHF-FM) marine radios. It is important to note that the Coast Guard discontinued monitoring the SSB-HF frequency of 2182 KHz over four years ago; nevertheless, many mariners continue to attempt to contact the Coast Guard using this frequency. Also, many mariners attempt to contact the Coast Guard using their EPIRBs, cell phones, SAT phones, and even NOAA weather electronics. Each of these communications devices has its own limitations and specific functional capabilities. Above: Example of Single Side Band High Frequency Radio

SSB-HF communications offer a greater transmission range when other options are not available. SSB-HF radios equipped with digital selective calling (DSC) are capable of triggering an alert at Coast Guard Communications Command and are an especially reliable means for initiating communications with the Coast Guard during distress situations.

The Coast Guard keeps watch on the Global Maritime Distress and Safety System (GMDSS) SSB-HF frequencies 4125, 6215, 8291 and 12,290 kHz in place of the old international radiotelephone distress frequency 2182 kHz. More detailed information on the SSB-HF and HF DSC frequencies on which the Coast Guard keeps watch for distress and safety purposes are listed here: Questions or comments concerning Coast Guard HF distress, safety and broadcast services may be sent to the Coast Guard Communications Command at

This safety alert is provided for informational purpose only and does not relieve any domestic or international safety, operational, or material requirements. Developed by Marine Inspection SME Sector Mobile and the Office of Investigations and Casualty Analysis. Questions or comments regarding this Safety Alert may be sent to


In case anyone wants the actual safety alert:

It’s amazing how many “experienced” mariners that I work with that are completely unaware of this and are lacking basic knowledge in all radio comms other than vhf.


Hell, I just wish we could get all the idiots to stop doing the distress relays on every one that comes through the super long range bands. It’s bad enough dealing with a dozen of them at a time on the VHF, but when the distress is 10,000 NM away… I’m not going to be able to do much good. :confused:


Like all knowledge, use it or lose it.


Nothing like a MF/HF distress relay from literally the other side of the planet to get you scratching your head at 0430.

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Even better when it comes up “Position: Undefined”

I remember hearing (from Rhode Island) around 1989 USCG Honolulu working a yacht in distress on phone and telling them “Awful sorry, but our nearest vessel is a week away from your position.” No idea what the yacht’s position was or what they had to say about that.

Anyone have experience hailing a coast station on HF for a comms check? Specifically in the Med or Atlantic. What station, range or freq have you used? In the days of sat comms this seems to have fallen by the wayside. DSC automatic replies have been consistently good.

I’ve tried the MF/HF DSC test calls with all the CG stations listed and have yet to get an automatic response. This is from the GOM. I usually think I’ve done something wrong until I test it with another ship that either has it on auto-ack or doesn’t just mash the cancel button when the set alarms.

I have. I used to install SSBs and for a comm check I would call them on 16 and ask them to listen on 2182 or I would never get an answer :roll_eyes: (back when 2182 was thing - not now!)
Now testing VHF DSC calls, at least some USCG stations do NOT answer the generic CG MMSI. You have to use the specific one for that station. HF may be similar.