DSC Basics

[hellosailor]

gamayun-
From what I've seen of both, whether voice can "make it through" as opposed to data, depends on which data protocols and equipment are being used. I don't know enough about what DSC is using to guess at that one. The good thing about DSC is that you don't have to try comprehending bad phonetics, hideous accents, and plain old sloppy speakers with marbles in their mouths.


Terry-
Satlink and Rebel Heart would be irrelevant to this. "Your" IP address could be assigned to you by a government administrator, much like a Soc. Sec. number. In which case, it could be free and permanent and not subject to commercial interruption. Or of course, you could rent or lease a block of them. All kinds of options are open--not just the "I've got a sleezy carrier who doesn't know how to communicate" problem that RH supposedly had.
If GE or Amana can figure out how to give my refrigerator a permanent IP address, then Icom or SH can do the same for my marine radio. And then I just have to contact a registry and register, or transfer, that IP address to my name. Same process that is used to transfer EPIRB ownership today, you go online, send an email, no money changes hands. (At least not in the US.)
If I change my phone number from an AT&T landline, to a Verizon cell, to a Sprint cell, to a Podunk VOIP company...somehow, it all just happens. The number stays with me and the cost is government capped, and CAN be zero if the carrier is not a pig. Some carriers take the full 30 days that they are allowed to take, in order to inconvenience the change. Other carriers manage to do it in 48 hours.


As I said, it is time the ITU took a look at the future. This stuff CAN all be integrated, and the costs of doing so can be less than the current costs of operating redundant and disconnected multiple systems with constant paperwork filing and updating.


Simple and quick and painless? No, good planning rarely ever is.


But consider: Give everyone a new phone number every time they move? Or just transition to the cellular system, and let the routers figure out where to ring the phone? That expensive new system has actually chopped prices way way down, not to mention, making life quicker and simpler for everyone. (Well, simpler until the carriers start playing games.(G)


Rustic-
You raise good points! I have seen both of the two top carriers "lose" SMS messages for 6-24 hours. This is not inherent to the system, however, it is the result of cheap corporations. Usually the excuse is that "it was on a server that went down" and that's really not an excuse, it means "we were too cheap to have redundant servers or acknowledgement protocols". In fact the old DARPA Internet design was originally based on every server passing a message to the next most likely server--and then if it did not get a success ack, it would try again on another route until the message WAS successfully passed on.
In that way the internet is exactly like high seas radio. You can call a vessel for days, but there's no assurance it has heard you. Well, the net provides for taking actions based on whether it does/not get an ACK from the destination. It also provides (if you use the master routing that the cellular carriers do) for constantly knowing "Where is this device? Is it active? Can I reach it?" and it would be able to say "Yeah, Davy Jones isn't answering his VHF, let's see if the HF or the cell or the satphone is active. Oh, heck, let's ring them all at once...or sequentially in a hunt group."
Heck, there were Telco's doing that 20 years ago, sequentially ringing all of your numbers, home, work, mistress, second home...until something picked up. No need for the human to dial around trying to find you, that's donkey work.


And again, government regulation and corporate greed plays a big role in reliability. You've probably heard one cellco advertising "the most reliable in the business". What you have never heard, is that none of them ever generates a busy signal--they divert calls to voice mail, and they may not send the silent "message waiting" signal for hours. Ooops.
After hurricane Wilma, the cellcos were up and running for 24 hours after the landline companies were flooded out. Then things changed, as the landline companies were required to have 3-day battery backup power, but the cellcos were not required to have backup power--and as a result they went down and stayed down. Part of the aftermath is that the FCC "encouraged" them to play nicer now, if any carrier has any fuel for any backup generator in a given area, they WILL service towers that belong to their competition, in order to keep the whole system up.
Big changes, and careful regulations can make them standards.


It certainly isn't less reliable than "let's see if he's in cell range. Or maybe VHF. Does he have HF-DSC? Oh, well how about the satphone, or at least, a text on the InReach?" By the time you can find all the numbers and turn on all the equipment...good routing can have them all ringing, or at least tell you "He's out of range."


You realize, if refrigerators and now, commercial aircraft (thank you, Malaysia) and even CARS are getting hooked into the web....what's the excuse for not hooking up boats? It isn't perfect? So? It can still be way better than it is.

[Rustic Charm]

Originally Posted by jackdale

Classes of DSC - from an Australian perspective.

VHF DSC technical specification

Thanks so these class A and D we have been talking about are only referring to VHF is it?

[nigel1]

This bit, I'm not so sure about From what AMSA tells us the only costal stations that will have DSC are those who have voluntarily purchased their own VHS with DSC sets? Would they not advertise their MMSI's if they had DSC?

Thats a good point RC, on the Sandringham Coast Guard web page (which appears to be the only CG station in Australia with a VHF DSC, there is no mention of the MMSI number, yet they have listed the number on their facebook page
https://www.facebook.com/CoastGuardV...37944072923933

[colemj]

Originally Posted by Sandero

Just curious... can any supply stats on how many or what percentage might be better of pleasure craft have upgraded to DSC?

Do we have any reports of how many times DSC was used in an emergency or distress situation? Is this making a difference? Saving lives? is there any way to know? It sure seems better...

Why don't they require DSC? and phase out the old VHF?

Pretty much any fix mount radio bought in the past 15 years or so in the US is DSC.

I don't think there are any non-DSC fixed radios being sold now.

Mark

[colemj]

This thread seems to have settled to the safety aspects of pushing the emergency DSC button. While important, that feature is actually the least interesting and useful to us.

DSC has lots of non-safety functionality that we use pretty much every day. I don't understand why people who hail each other 400 times each day don't use their DSC calling instead. It certainly would make things more pleasant for the rest of us.

In some places, hailing channel traffic is so bad that we either turn our volume down or go off channel and rely on our friends to call us privately by DSC. Before anyone jumps on this as irresponsible, consider that in these anchorages everyone else is also off channel because they spend their days following hailed conversations around like a party line (what is wrong with these people?????). So it wouldn't matter if we were paying attention to a hailing channel.

Mark

[Rustic Charm]

Originally Posted by colemj

Pretty much any fix mount radio bought in the past 15 years or so in the US is DSC.

I don't think there are any non-DSC fixed radios being sold now.

Mark

THat's what 'should' be the case in Australia too.. But unfortunately you can still buy non DSC units. And up until only about two years ago, non DSC units were mainly in the shops.

[Rustic Charm]

Originally Posted by colemj

This thread seems to have settled to the safety aspects of pushing the emergency DSC button. While important, that feature is actually the least interesting and useful to us.

DSC has lots of non-safety functionality that we use pretty much every day. I don't understand why people who hail each other 400 times each day don't use their DSC calling instead. It certainly would make things more pleasant for the rest of us.

In some places, hailing channel traffic is so bad that we either turn our volume down or go off channel and rely on our friends to call us privately by DSC. Before anyone jumps on this as irresponsible, consider that in these anchorages everyone else is also off channel because they spend their days following hailed conversations around like a party line (what is wrong with these people?????). So it wouldn't matter if we were paying attention to a hailing channel.

Mark

Well again, in Australia 'my experience' is so far I've not been able to reach anyone on trying to do a radio to radio call. There is no coast station I can call and the ships I've tried calling when they pop up on my AIS, so far for the past two years that I have had DSC, NONE have ever answered..

Given this discussion I intend on finding someone nearby with a DSC and testing it. I was down at the slip yesterday where my boat is and I asked two people but one didn't know what DSC was (so if his boat has it he doesn't know about it) and the other said he's not upgraded to DSC yet).

As I said, it's still pretty new technology down this way..

[nigel1]

In the US, does the Coastguard use DSC alerts before broadcasting safety and weather messages?

UK Coastguard are sending DSC alert before broadcasts, and puts in Ch 16 as the "working" channel. They will then make a voice broadcast on 16 before going over to the proper working channel.

On the Irish side (Eire), the Coast Guard also send a DSC alert before sending safety messages, but they set the actual working channel in the DSC Alert. If your DSC radio is set to automatically comply, it will change to the working channel used by the CG.

Just wondering what the USCG procedure is.

[hellosailor]

" Why don't they require DSC? and phase out the old VHF?"
Since VHF is entirely OPTIONAL on recreational vessels, I would expect that if 100,000 or so "older boat" owners were told "Oh, you have to throw out your radio and spend $150 on a new one" they would simply throw out their radios and use their cell phones.


Or, take up pitchforks and torches and roast the party giving the orders.


So, really, who wants to shoot themselves in the foot by making that a requirement, if a boater is too stupid to figure out for themselves that it IS safety equipment? Or just has other priorities? You know, the crabs got a right to eat, too.


Anyway, the various racing rules HAVE all been raising the ante on VHF equipment, so for the folks most likely to say "I don't care about the forecast, we've got a race to win" that part of the market has been largely required to update.


I think letting the new equipment take over gradually is probably the least onerous and most appropriate way to do it. Someone can't or doesn't want it? OK, they're not required to have a VHF at all, so, no loss there.

[Rustic Charm]

Originally Posted by nigel1

Thats a good point RC, on the Sandringham Coast Guard web page (which appears to be the only CG station in Australia with a VHF DSC, there is no mention of the MMSI number, yet they have listed the number on their facebook page
https://www.facebook.com/CoastGuardV...37944072923933

Yeah, I'm going to do some further research in this whole area as I think what is happening is the very same thing that occured in the Epirb thread where there are some significant differences world wide and people from different nations are just assuming DSC is the same world wide. I might even make some phone calls to AMSA and see what I can find out of what is available in Australia.

So far from what I'm ascertaining from google and from this thread is the following:

• Australia's main DSC network is through HF SSB sets equipped with DSC and not through VHF.
• Australia's costal stations are only set up for DSC with these HF SSB sets and not VHF.

That's as much as I know about HF SSB DSC sets, other than they cost thousands. IN regards to VHF

• You can't use the 'test' function on VHF DSC sets.
• There is only one dedicated costal station that is set up for VHF DSC.
• There may be other 'volunteer' costal stations who have DSC, but this is not organised and widely supported.
• VHF sets being sold without DSC is still very common.

And I'm quite confused around 'catagories'. The links provided so far don't help. I'm suspecting Cat A radios relate to HF SSB units and not VHF as I can't seem to google any Cat A VHF radios.

And from the AMSA web site

There is no official MF or VHF DSC shore infrastructure in Australia. Vessels fitting MF and VHF DSC equipment should realise that this equipment can only be used for vessel – to – vessel alerting in the Australian region. There is no official shore-based MF or VHF DSC infrastructure, but there are a number of volunteer marine rescue (VMR) stations that have installed VHF DSC and a check with your local VMR should be made.

[jackdale]

Classes of DSC

Class A equipment, which includes all the facilities defined in the international standard to comply with the GMDSS requirements for merchant ships. Class A DSC equipment uses two antennas - with one dedicated to the DSC receiver. They can be VHF, e.g. (http://www.cobham.com/media/960269/s...duct_sheet.pdf)

Class D equipment, which is specifically designed for recreational vessels. It provides VHF DSC distress, urgency and safety as well as routine calling and position polling. Class D equipment includes a dedicated channel 70 DSC receiver, so you will never miss a DSC call.

[Rustic Charm]

Originally Posted by jackdale

Classes of DSC

Class A equipment, which includes all the facilities defined in the international standard to comply with the GMDSS requirements for merchant ships. Class A DSC equipment uses two antennas - with one dedicated to the DSC receiver. They can be VHF, e.g. (http://www.cobham.com/media/960269/s...duct_sheet.pdf)

Class D equipment, which is specifically designed for recreational vessels. It provides VHF DSC distress, urgency and safety as well as routine calling and position polling. Class D equipment includes a dedicated channel 70 DSC receiver, so you will never miss a DSC call.

So all SOLAS vessels (e.g commercial vessels of certain tonnage) must have class A and if they have a VHF it must be a class A VHF ?

And Class D is only about VHF radio's?

[jackdale]

Originally Posted by Rustic Charm

So all SOLAS vessels (e.g commercial vessels of certain tonnage) must have class A and if they have a VHF it must be a class A VHF ?

And Class D is only about VHF radio's?

I believe that is correct.

[transmitterdan]

Originally Posted by Rustic Charm

And I'm quite confused around 'catagories'. The links provided so far don't help. I'm suspecting Cat A radios relate to HF SSB units and not VHF as I can't seem to google any Cat A VHF radios.

Goggle 'class a VHF dsc' and you will be rewarded. There is no such thing as "category a dsc".

I agree with previous post that all this worry about how emergency distress works misses the point of this thread. The point is that dsc VHF radios offer several really useful and neighbor friendly features. Learn how to use them and tell others so this technology can benefit everyone more.

1) make sure your next VHF radio is DSC. (probably can't buy a non dsc new one nowadays)
2) get an MMSI number and put it in the radio.
3) connect your radio to an NMEA GPS data source.
4) get your friends to do #2 & 3
5) start calling your friends, marina, etc. with MMSI on a regular basis. That way you know it works.

None of us are going to change Australia's decisions about DSC. That's ok.

[Rustic Charm]

Originally Posted by transmitterdan

Goggle 'class a VHF dsc' and you will be rewarded. There is no such thing as "category a dsc".

I agree with previous post that all this worry about how emergency distress works misses the point of this thread. The point is that dsc VHF radios offer several really useful and neighbor friendly features. Learn how to use them and tell others so this technology can benefit everyone more.

1) make sure your next VHF radio is DSC. (probably can't buy a non dsc new one nowadays)
2) get an MMSI number and put it in the radio.
3) connect your radio to an NMEA GPS data source.
4) get your friends to do #2 & 3
5) start calling your friends, marina, etc. with MMSI on a regular basis. That way you know it works.

None of us are going to change Australia's decisions about DSC. That's ok.

Non DSC vhf and hf sets are still very common for sale in Australia.