Got on the boat today, pulled out my GX2150 manual, and did some more reading on my radio's DSC. Tom, I don't really see a need for a seminar on DSC, as I think it's just as easy to somewhat hijack the event thread here and continue discussing it as we have. John gave some very good advice. And I learned today that setting up a group listing is a lot easier than I thought it would be. (Originally I thought I'd have to enter everyone's boat name and MMSI into my radio's directory. Yes, if you plan on calling other boats separately you have to do that, and yes it is time consuming.)
For those others that are interesting in using their newer DSC radios, if your radio is capable of group listing, you only have to input one MMSI number. The first numeral is going to be 0, and the 2150 defaults to that (and it can not be changed.) Pull out your operating manual to learn how to input the number, but my radio it's simply entered in the DSC setup under group. I named my group STJOHNCBRAT. My manual suggests using the MID for the next 3 numbers after the 0, which are the numbers 338 for the USA. For the last 5 numbers, I just chose the Hontoon State Park zip code: 32720. So, if you desire to use the group call at Hontoon, you should enter the MMSI in the group list as 033832720. All boats that have this MMSI number in their group calling list will get the signal. (Which means if for some reason some other group also thought the same way I did, we just simply have to change one number and we're back in business.)
Very simply, the DSC can be used to "page" others in the group, rather than making a call out on the radio. Once a group call is made, all boat radios that have that MMSI number inserted will alert. Just hit any key to silence the alert and your radio will automatically change to the frequency the sender is requesting. In our case, Tom has already said we'll use 72, so that is the frequency to enter in your radio when asked, if you are doing the transmission.
Why would anybody want to use DSC this way? Well it allows you to tell your buddy or group to go to another chosen channel, without announcing it to everyone else listening. You want to tell your buddy where the hot fishing is without letting anyone else in on the secret? Want to have a conversation without everyone else tuning into that channel to listen? Send the channel request via DSC and no one else will know unless they are in your group, or you send it to their MMSI.
I think this would be a great tool for gatherings like ours, or yacht clubs, etc. Maybe I don't want to constantly monitor 72? No need to if we used DSC. If somebody wanted to transmit to the group, just do a group call with your DSC, wait shortly for folks to acknowledge so their radios make the automatic channel change, then transmit over the radio as you normally would. Of course, this only works if you have one of the newer DSC VHF radios that has the group list function, and have the group MMSI entered in your radio's directory.
BTW, Don't confuse this with your radio's assigned MMSI number. The entry that you can only do once, and then it's permanent in your radio!!!! The Group MMSI, is entered into the directory. Kind of like your phone has it's own phone number, but then you have a directory with other phone numbers. But the cool thing about the DSC group listing, is it's like giving your phone a temporary phone number that it can also ring from! IN this way, think of the old Party Lines!
Colby