Another Dumb DSC VHF Question

[S/V Alchemy]

Originally Posted by AD 2

Thanks. I've been skimming the manual, and will go into it more when I get back down to the boat tomorrow. It's a real eye closer, though...

Whereabouts in Toronto are you? We're at MMC.

Do you mean Mimico Cruisng Club (MCC)? I was at Etobicoke for a couple of seasons as my boat partner of the time was there. My main boat is at National YC. You can see it at the link in my signature block below.

The reason to use MMSI and DSC is pretty straightforward (you need a Radio Operator's Certificate with DSC endorsement, by the way...it's a good class).

Besides the MMSI number referencing your boat, the "digital" side of things means greater range than sometimes dodgy "analog" voice transmission can cope with. Also, ch. 70 DSC calling is more secure when you have boats calling MMSI to MMSI when compared to Ch. 16 calling. Lastly, a DSC Mayday can be easier to relay to shore if you (for instance) are dismasted and just have a handheld with a DSC button. It's well worth the time invested, in my view, to activate it.

Throw in the AIS factor, however, and it becomes part of a "total awareness package" wherein the RADAR shows you the shore line on foggy nights and the AIS shows you the ship traffic. Anything neither shore nor ship is probably a non-AIS equipped boat. Call them with their MMSI and you can tell them to hold their course and from which direction you'll be making a close approach. It's as if the blind had talking white canes.

[AD 2]

Yes we are at Mimico, only a friendship gate away from EYC. I just picked up the radio to replace an earlier non DSC model that was in the boat when we got it last year. I'm especially enamoured of the e-distress feature, and am looking forward to checking out the quality of the digital voicestream. I'm just waiting for the Ministry to send out the MMSI. And down the road, AIS is definitely on the radar. As they say.

I was checking out your blog – very nicely written. Alchemy’s a sweet looking boat. It looks like we have similar outlooks on life in general, particularly in the reduce/reuse/recycle department, and in not underestimating the value of the lo/no technologies of our forebears in the rush to embrace the shimmering gadgetry of the future. We put up substantial quantities of food in season, munching it leisurely for the rest of the year, and I very much enjoy the fermentation method of barley preservation, infusing an antibacterial agent (say, hops) and bottling the result under slight CO2 pressure. A skill’s no less of a skill for being ancient. As Isaac Newton may have said had it occurred to him, if we have trains, planes and automobiles (also boats), it is because we are driving over the heads of people who traversed continents on their feet.

We took our first baby boat steps this weekend, a stately procession of 12nm all the way to Oakville, and the radio was fine. Also our first baby radio steps, come to think of it. You are way further along your sailing trajectory than we are - who isn't? - so I very much appreciate the clarity of your kind and sagely advice.


Billy

[goboatingnow]

Also, ch. 70 DSC calling is more secure when you have boats calling MMSI to MMSI when compared to Ch. 16 calling. Lastly, a DSC Mayday can be easier to relay to shore if you (for instance) are dismasted and just have a handheld with a DSC button. It's well worth the time invested, in my view, to activate it.

Not really any security at all, the voice call is still as normal and can be detected by any scanning VHF.

[cal40john]

Originally Posted by AD 2

Yes we are at Mimico, only a friendship gate away from EYC. I just picked up the radio to replace an earlier non DSC model that was in the boat when we got it last year. I'm especially enamoured of the e-distress feature, and am looking forward to checking out the quality of the digital voicestream.
Billy

Only thing digital is channel 70.
Pushing the distress button sends your MMSI number and GPS location digitally. When the coast guard acknowledges your signal the radio automatically is switched to channel 16, where you talk which them just as you used to on an analog open to everyone channel.

You can place a call to another boat using their MMSI digitally. Only the boat being called announces your desire to talk. Their radio will change to the analog working channel that you have selected when they acknowledge. You then talk on a normal analog open to everyone channel.

There are other functions such as ask for your buddies GPS location which is sent to your radio and displayed.

John

Can You Hear M e?

[jeremiason]

DSC is great when you have multiple boats cruising together or even racing. You can DSC them and switch them all to a working channel at once by selecting preprogram DSC numbers.

Another great feature is the ACK function, which allows you to ask for a status check from buddy boats... If they ACK, you know everything is OK.

The Request Position Report, in conjunction with a chart plotter is a very cool function. If you radio is connected to NEMA, the position will appear on most chart plotters as a waypoint. This is good when searching for a buddy boat in a crowded anchorage or see where they are if you are cruising.

DSC is a great tool!

[fairbank56]

Originally Posted by goboatingnow

to prevent MMSI spoofing, thats why , ITU says 3 goes max, some have less.

The latest ITU DSC technical spec that I have doesn't give a number, it simply states "Once stored, it should not be possible for the user to change the MMSI number without advise from the manuafacturer."

Eric

[fairbank56]

Originally Posted by S/V Alchemy

Lastly, a DSC Mayday can be easier to relay to shore if you (for instance) are dismasted and just have a handheld with a DSC button.

While a station receiving your DSC distress call should respond to the vessel in distress via voice IF the DSC alert is never acknowledged and may also contact the coast guard via voice to inform them of the alert, DSC digital relaying is against the rules and class D units (recreational) are not even capable of relays. Commercial ships with class A were capable of manual digital relays but that has been against the rules for some time.

Eric

[goboatingnow]

Originally Posted by fairbank56

The latest ITU DSC technical spec that I have doesn't give a number, it simply states "Once stored, it should not be possible for the user to change the MMSI number without advise from the manuafacturer."

Eric

Yes I think it may have changed

Dave

[fairbank56]

I dug up earlier versions of the standard as far back as 1997 and none of them gave a specific number. The early versions state, "The MMSI should be stored in the DSC unit and it should not be possible for the user to easily change it." I think most manufacturers just allow you to screw up once. After that, it requires the programming software to change it.

Eric

[AD 2]

Thanks John, I can see I have a bit of exploring to do in the menus.

Originally Posted by cal40john

Only thing digital is channel 70.
Pushing the distress button sends your MMSI number and GPS location digitally. When the coast guard acknowledges your signal the radio automatically is switched to channel 16, where you talk which them just as you used to on an analog open to everyone channel.

You can place a call to another boat using their MMSI digitally. Only the boat being called announces your desire to talk. Their radio will change to the analog working channel that you have selected when they acknowledge. You then talk on a normal analog open to everyone channel.

There are other functions such as ask for your buddies GPS location which is sent to your radio and displayed.

John

Can You Hear Me?

[goboatingnow]

Originally Posted by fairbank56

I dug up earlier versions of the standard as far back as 1997 and none of them gave a specific number. The early versions state, "The MMSI should be stored in the DSC unit and it should not be possible for the user to easily change it." I think most manufacturers just allow you to screw up once. After that, it requires the programming software to change it.

Eric

Some radios allow upto to three

Dave

[S/V Alchemy]

Originally Posted by AD 2

Yes we are at Mimico, only a friendship gate away from EYC. I just picked up the radio to replace an earlier non DSC model that was in the boat when we got it last year. I'm especially enamoured of the e-distress feature, and am looking forward to checking out the quality of the digital voicestream. I'm just waiting for the Ministry to send out the MMSI. And down the road, AIS is definitely on the radar. As they say.

I was checking out your blog – very nicely written. Alchemy’s a sweet looking boat. It looks like we have similar outlooks on life in general, particularly in the reduce/reuse/recycle department, and in not underestimating the value of the lo/no technologies of our forebears in the rush to embrace the shimmering gadgetry of the future. We put up substantial quantities of food in season, munching it leisurely for the rest of the year, and I very much enjoy the fermentation method of barley preservation, infusing an antibacterial agent (say, hops) and bottling the result under slight CO2 pressure. A skill’s no less of a skill for being ancient. As Isaac Newton may have said had it occurred to him, if we have trains, planes and automobiles (also boats), it is because we are driving over the heads of people who traversed continents on their feet.

We took our first baby boat steps this weekend, a stately procession of 12nm all the way to Oakville, and the radio was fine. Also our first baby radio steps, come to think of it. You are way further along your sailing trajectory than we are - who isn't? - so I very much appreciate the clarity of your kind and sagely advice.


Billy

Thanks for the kind words, Billy. The Morgan OI 33 is a sweet ride, if not a champ to weather (like mine, but unlike my equally old Viking 33). You should throw it into a nice brief Lake Ontario squall to get in practice time for the proper ocean. Lake Ontario, it is said and I concur, can give you plenty of practice dealing with short, heavy chop and intense squalls, and if you can handle that here without breaking crew or gear, you are well on the way for salt water. Just reef her well down, tether in, dog down the hatches and go looking for trouble. The Morgan should prove a good teacher.

[S/V Alchemy]

Originally Posted by fairbank56

While a station receiving your DSC distress call should respond to the vessel in distress via voice IF the DSC alert is never acknowledged and may also contact the coast guard via voice to inform them of the alert, DSC digital relaying is against the rules and class D units (recreational) are not even capable of relays. Commercial ships with class A were capable of manual digital relays but that has been against the rules for some time.

Eric

Thanks for the clarification. I was referring to a voice response in the situation where a boat with perhaps a five-watt handheld at deck level sends a DSC distress call seven or eight miles downrange from a boat closer to shore and CG monitoring. The CG may not, for a variety of reasons, be able to hear the handheld DSC or the voice, but the intervening vessel may be able to be the middleman by voice with both boat in distress and shore.