I'm pleased to let everyone know that we have been allocated a Group MMSI number by Ofcom - but what does that mean?
If you have a DSC VHF radio, then you will (or should!) have an MMSI number unique to your radio. It's essentially your radio's "phone number". Apart from identifying you to the coastguard if you use the red "panic button", you can also use MMSI to call any other boat - if you know their MMSI number. The advantage over just calling by voice is that you're not dependent on the other boat listening on the same channel, an MMSI call will produce a ring tone on the receiving radio whatever channel they're currently on.
The only problem is that you need to enter the MMSI numbers of all the other boats you might want to call into your own radio's phone book. This is a rather tedious process that most people can't be bothered with!
This is where a group MMSI number comes in. If all boats sailing in a group put the group MMSI into their radios, then any one of them can easily make a group call which alerts all the other boats in the group (assuming they're in range). Everyone needs to put just one number into their radios. This can be very useful for you, our members, when sailing together. You'll be able to call all the other boats in the group even if you've forgotten to agree a working channel, or if someone's not listening on the right one.
I'm therefore recommending all members with DSC radios to program our group MMSI number into their sets. You'll probably have to check the manual for how to do it - I've put links to online manuals for a few well-known makes below. While you're at it, have a look at how to use the group MMSI!
Typically you use the menus to select DSC-call -> Group -> Group-name -> Channel -> Send, and other radios will then sound an alert tone. On receiving radios you usually have to press a button to accept the call, which switches the radio to the requested channel. From then on you speak and listen the same as a normal radio voice call.
In particular, I'd like to ask everyone who's going to be at the Big Mac event to put our group MMSI into your DSC radios, to simplify the process of keeping in touch with all boats.
Our group MMSI number is 023200170
Some popular DSC VHF manuals
Fixed
Handheld
Rick Jones (Treasurer), former 26X & 19 owner, Isle of Wight
Well done for this Rick - your a star - not only do you sort out the Group MMSI but you spend the time to help members use it.
I'll certainly add it to my radio when I'm next aboard.
Regatds,
John
great idea Rick, thanks. Now all i need to do is remember to programme it when Stargazey is back in the water
I've done that on my Standard Horizon Eclipse - seemed to work ok
Mike
Hi all
Sounds like a great idea but I’m a little confused (as usual). From the info I’m reading, the MMSI number is unique to the vessel and linked to your personal licence, which you are legally required to have, how does a group number work. Sorry if I’m missing the obvious.
Hi Keith
You're correct, you do have a unique MMSI assigned to the vessel, which you register with your licence (you can also have another MMSI assigned to a handheld radio). You can enter this main MMSI into the radio only once, it cannot subsequently be changed.
But DSC radios also have a "group call" feature. This is more flexible, enabling you to belong to one or more radio groups. Group MMSI numbers are a different series, they always start with "0". In the group-call section of the radio setup, you enter a Group MMSI number. You can then make a group call, which will alert all other radios that have the same group number. Likewise, you will get an alert if any of those other radios makes a group call. You can enter as many Group MMSI numbers you like, enabling you to belong to multiple groups at the same time.
Unlike OFCOM in the UK, not all jurisdictions actually allocate group MMSI numbers, and you're free to invent your own. This is the reason for using an initial "0" so group numbers are never confused with individual numbers. A standard technique is to take an individual number, add a leading "0" and drop the last digit. I suspect that many UK sailors do this anyway, but as I wanted a number for the MOA I thought I'd better do it properly!
Rick Jones (Treasurer), former 26X & 19 owner, Isle of Wight
Hi Rick
Thanks for clarifying it. It makes sense now.
Rick,
You've got me thinking (ok a rare event). Can a DSC radio call a group MMSI that it isn't programmed as a member of ?
That way you could call a group but not be called by that group.
Just wondering.
Dave.
Dave Newton Sailbadthesinner
Good question - no idea!
It possibly depends on the radio. With an individual call you can usually type in the MMSI you're calling, it doesn't have to be in the memory. I suppose if the radio allows you to do the same with a group call, then it's an outgoing call only (unless the radio automatically stores the number!).
I need to play with mine, I haven't even looked at storing group numbers yet.
Rick Jones (Treasurer), former 26X & 19 owner, Isle of Wight