Using DSC

colbysmith · Posted: Wed Oct 28, 2015 7:11 pm Post subject: Using DSC

I had first replied with this comment to another thread, but feel it should have it's own related thread:

Bob, regarding DSC. I don't know what the commercial requirements are, but I doubt most folks know how to use it, or even have it hooked up properly. This past summer I made several attempts to use my DSC to contact other vessels, both commercial freighters and small private yachts. None of which replied back. TO be honest, I don't even know if my radio's DSC is working properly as I have made numerous attempts in the Door County area to send the test code to the USCG, with no response. However, I also sent a test out in Port Washington, and got an immediate reply. (So I think my radio's DSC IS working. But to be sure, I have it at the manufacturer now to be checked out.) Finally, while I got no reply back to my test signal while at the Alton gathering (near St. Louis), I did try using DSC to contact a private yacht at the end of the dock. (In these contacts with other boats, it is in connection with their AIS signals that I'm registering, and then trying to initiate contact using the DSC function. After not getting any response, I actually walked down and spoke to the owners. Come to find out, their radio was alarming (in response to my DSC call), but they didn't know what it was. After some conversation, they offered to "work" with me again on the calls, but were unable to figure it out on their end. (From what I understand, a receiving radio should change to the requested frequency and then the operator can acknowledge and continue the call.) While in the North Channel earlier this summer, I also requested the gentlemen that does the morning broadcast, to announce my MMSI, and ask any fellow boaters to try hailing me by DSC. I did not receive any calls.... Anyway, my point is, I question how many even know how to use their DSC? And it only works if it's connected to an external GPS, or has it's own GPS, to transmit location. Ok, sorry about getting off subject a bit. Think the captain did the right thing in firing off a flare! Colby

That pretty much explains the situation I've had trying to test the DSC function on my radio. I just spoke with tech services at Standard Horizon, and they said my radio tests out fine. They also did the DSC auto test there with the USCG, and got a reply within about 6 seconds. So my next question is, has anyone else used the DSC on their radio's, and done the test function with the Coast Guard? If so, did you get a response? Particularly in the Lake Michigan Sturgeon Bay or Mississippi River St. Louis areas?

thataway · Posted: Wed Oct 28, 2015 10:23 pm Post subject:

Colby, I have not used the DSC function on my own radio, but it has alerted on several Maydays. In areas beyond shore station range, I have heard other stations relay to USCG, I have also observed nearby vessels respond to the distress.

I am sure that you are correct that few boaters understand DSC. Many radios (maybe the majority) are not programed with the MMSI number e(either the Boat US or FCC--and most boaters do not know the difference)

I don't know what the current situation on outside Vancouver Island is on Rescue, but many times in Canada, I found Lighthouse keepers relaying distress calls, with a lack of Canadian CG response, in remote ares. Thus the idea of DSC is alarming any boater's radio-and hopefully the boats will respond. The mechanisms of voluntary use of DSC for calling a single vessel, calling a group, or a distress DSC are all different.

Here is USCG protocol for DSC (and note that is is also on 2182 HF

ssobol · Posted: Wed Oct 28, 2015 11:15 pm Post subject:

The DSC function and the distress function of current VHF radios are related but not identical features. You can use the DSC function of your radio without sending a distress signal.

The DSC allows you to call a particular receiver if you know its MMSI number. The usual analogy is calling a particular phone number. It only works if you know the number before you place the call.

A DSC equipped radio can send a distress signal which contains digital information such as MMSI number and position info. This simplifies rescue operations because the responders can know who you are, get position information, and boat description without someone having to read off a lat/lon from some other device (if you have it wired up right) and/or give this information over the radio.

Of course, a distress signal from a VHF radio has a limited range (about 25 miles from a good set up depending on terrain). A EPIRB or PLB has an effect range that pretty much covers the entire planet. I'm guessing that a distress signal from an EPIRB or a PLB will probably mobilize a rescue faster than a VHF DSC call (less verifying if it is a false or inadvertent message).

hardee · Posted: Thu Oct 29, 2015 12:35 am Post subject:

ssobol · Posted: Thu Oct 29, 2015 10:10 am Post subject:

I would think that you could use the DSC function to call someone else without a valid GPS to the radio.

I think that part of the problem is that once a radio has a MMSI number programmed, it can only be reset by a service center. You can transfer the MMSI number in the radio to another user when you sell the radio (instead of reprogramming it) but that involves some paperwork.

hardee · Posted: Thu Oct 29, 2015 10:45 am Post subject:

colbysmith · Posted: Thu Oct 29, 2015 12:52 pm Post subject:

DSC, either individual calling or distress, is not dependent upon GPS. However, it will not transmit your position if you do not have an internal GPS in the radio, or have it connected to your chartplotter. I'm not sure exactly how the MMSI number is tied in with everything, other than as a means to identify your radio. (And for the USCG to look up important data on you if you send the distress signal using DSC.)

Bob, I've only heard DSC used once in the few years I've had this radio. And that was an all call by the Canadian GC while I was in the North Channel last summer, looking for assistance with an overturned kayaker during all that wild wind that was blowing while we were there.

I'm just learning how it can be used for regular communications, but hard to really make use of it in my locations of boating. DSC use among C-Brats at gatherings would diffinitely be a benefit!

Colby

rogerbum · Posted: Thu Oct 29, 2015 4:45 pm Post subject:

thataway · Posted: Thu Oct 29, 2015 5:24 pm Post subject:

One important item to remember (and it brings up that old issue of a ship station license if you make "international voyages"!)

Many mariners use Boat US (and some other agencies) who assign a MMSI number, without a FCC ship station license. This information is transmitted to the US CG.

From the Boat US web Site:

beermanPDX · Posted: Thu Oct 29, 2015 5:25 pm Post subject:

If you own at least two radios with DSC and have your MMSI number entered in them, you can test out DSC on your own.

Ex. I have two fixed mount radios and a handheld, all with DSC. They all have my MMSI number. If I send out a position request message to my own MMSI number, the other two radios get it. I can see and verify the messages and coordinates my radios are sending out.

rogerbum · Posted: Thu Oct 29, 2015 5:49 pm Post subject:

Thanks for the reminder Bob. When I registered my MMSI number, I did it through the FCC for that very reason - e.g. I planned to be in Canadian waters and I wanted to not only have the license but to be sure that my MMSI number and info was in the international databases.

Rob - I don't know why I didn't think about that. I also have two fixed mount radios with MMSI# and DSC. Each one is attached to it's own chart plotter but on has an internal GPS (newer Std. Horizon) and the other does not. Both have AIS.

colbysmith · Posted: Thu Oct 29, 2015 9:51 pm Post subject:

Regarding Canada and Boat US assigned MMSI numbers. While it is true that the MMSI numbers assigned by Boat US are only for use in "domestic" waters, in real life operation, if you are operating in "border" waters, Canada will very likely be able to get your MMSI information if you send out a DSC distress signal. So if you need to signal a distress and want to use DSC, USE IT. (I forget where I got this info, but it was from some official Canadian types somewhere while we were up in the North Channel.) And besides, if you have GPS hooked up, the most important thing is having a position to search in! Colby

hardee · Posted: Fri Oct 30, 2015 3:13 am Post subject:

rogerbum · Posted: Fri Oct 30, 2015 5:52 am Post subject:

They will get the distress call and your position. They will probably not get the info associated with you MMSI #. But the position is the most critical piece of info and I doubt there would be a delay in response.

hardee · Posted: Fri Oct 30, 2015 4:40 pm Post subject:

Roger, you are right there. And I doubt they would even go looking for the other info.

One thing I learned from this thread and reading about rescues where the guy in the water watches the helo come right toward him and the turn and go away.

Put my MMSI numbers into my Handheld VHF's.

Never even thought about that. Thanks C-BRATS, What a great place.

Harvey
SleepyC Moon