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xkcd #3169: EPIRBs
(imgs.xkcd.com)
Title text:
'Oh no, the box is drifting out into the harbor!' 'Yeah, I wouldn't worry about losing it.'
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3169/
For those who didn't know: EPIRB = Emergency Position Indicating Radio Beacon. Sends an emergency signal via satellite and terrestrial RF. They can be triggered manually, but they also trigger automatically if salt water shorts two exposed pads for a certain amount of time (a minute, I think).
Once triggered it will get a GPS fix and transmit a distress signal via satellite as well as terrestrial VHF. It is programmed with the MMSI of the ship it belongs to.
Works all over the world, although they take a bit longer to successfully transmit the signal in the polar regions as they then have to rely on LEO sattelots in polar orbits.
Source: I have a GOC, and I also used to work with marine electronics. I've programmed hundreds of these. Mainly ~~Jordan~~ Jotron TR60 (Ducking autocorrect). Some from McMurdo too, don't remember the model name.
Fun fact: A coworker did have to make the phonecall of shame to the coastal radio after accidentally dropping one overboard.
what does programming them include? Just a ship identifier?
It's been a while, but off the top of my head: MMSI (which is basically the radio installation identifier. Same number is used for AIS), and an ID digit (0 in wheelhouse, 1 on starboard bridge wing, 2 on port, etc)
I have a handheld one—to float with me in a liferaft, etc—and it gets registered to a vessel or vehicle. Whenever I want to use it on something different, contact the federal government, advise of the new vessel ID or vehicle registration, and it's now associated with the new one.
I don't think it matters much since it is a beacon after all, but I think it helps in searching. Also, a lot of other details are registered along with it so they know who to send the tens of thousands in fines to if I somehow bypass all three "Are you really sure?" switches and fire the thing off inappropriately.
Any chance what you have is not an EPIRB, but a SART? SARTs are only registered with beacon ID and doesn't require programming. Shows up on radar and sometimes AIS also. No sat comms involved.
Registration Status: Registered.
Beacon Type: EPIRB.
406MHz GPS (Cat. 2) 66-channel. Beacon Status: Operational.
Battery Expiry Date: 01/10/2028.
It's UIN—which I obv won't give lol— doesn't hold an MMSI. The main reason being EPIRBs aren't just for marine craft.