I am going to ask a dumb DSC/VHF question!

Ok, I am gonna ask a question that may be obvious but what the heck- perhaps it will help others. *So the last 2 weekends I have my VHF do this out of the blue:


We never used DSC previously and I should know this already but darned if I am not sure. *I am familiar with the fact that DSC can be used to "hail" a particular vessel if you know their MMSI number but it is also used as a distress call to USCG and any nearby vessels. * No distress call was sent out with these messages and no other vessels hopped on the VHF answering *distress call for help. *The VHF would beep like that until I turned the VHF channel and then it went away.

So....is this a case of a mistaken distress call or what? *Maybe this is a good time to discuss DSC alerts, what they sound and look like whether just to hail you or to sound a mayday, how to respond, etc. so as to educate everyone. *I figure if superdiver can post about his maiden voyage docking solo on one engine and all that fun reading material, I can ask this probably very obvious question. **

Last question- I've read a lot about registering for your own MMSI number which I plan on doing this week and read a lot about them being tied into GPS but anyone know if there is a way to tie your DSC enabled VHF into a laptop GPS program?

Woodsong

It is the radio looking for GPS coordinades as part of the DSC system

You can cancel it by pushing the enter button or hooking up to the gps so it can obtain the information

*

Allan

Hm.. That doesn't make sense to me. We've put about 165 hours on the engine since we bought the boat August 2010 and only in the last 2 weekends has it ever done this. I don't (as far as I know) have a registered MMSI # so that ruled out someone trying to call me and my radio did not switch channels automatically as I understand DSC does when you are being "hailed" via DSC.

The MMSI of the caller is shown as 338108105 on your VHF display.* The leading three numbers of the MMSI are country identifiers.* The US uses 338, 366, 367, 368 and 369.* Canada uses 316.* You can find a complete list of country codes at http://en.wikipedia.org/wiki/Maritime_identification_digits .

This particular MMSI is not registered to anyone by the Federal Communications Commission.* You can search for MMSIs and other data by using this FCC site: http://wireless2.fcc.gov/UlsApp/UlsSearch/searchShip.jsp;JSESSIONID_ULSSEARCH=8HzjTXBP2JDwWHhcTL3z94Cn4JPWkx2WssbGV0q6fHZYVsstglb2!-1933172191!1840754471.

Since this MMSI does not*show up on the FCC search it implies that this is an erroneous MMSI or an expired MMSI.* It could be that a previous owner of the VHF radio sending the signal entered his MMSI then sold the boat or the radio and deactivated his MMSI.* The new owner of the boat /radio never reset the MMSI to a new assigned number thus the radio is sending out the last know MMSI, which obviously is inaccurate.

On you display is says ALL SHIPS.* That means the vessel using 338108105 has sent out either a PAN-PAN or SECURITY to all ships within radio range.* There are multiple different types of DSC calls:* DISTRESS (MAYDAY), URGENT (PAN-PAN), SAFETY (SECRUITY), GROUP (a group of boats) and INDIVIDUAL (a call to a specific vessels MMSI number for either a personal conversation or a position request).* If you are getting the same MMSI being sent repeatedly it means someone is playing with the other radio.* The good news is that they are not sending out DISTRESS signals and causing all sorts of worry by your local law enforcement agencies.

I suggest you read the owners manual for your VHF radio.* All manufacturers have information in their manuals about using Digital Selective Calling and how to set up your radio.* The manual will also discuss NMEA in and out connections to allow your radio to have a GPS signal in order to respond to position requests from friends and to enable the radio to send received position indications to you personal computer hosted navigation system or to a chart plotter.* I use Rose Point Navigation Coastal Explorer on board the boat and have my VHF sending NMEA data from the radio to the computer through a Brookhouse NMEA multiplexer and a serial port on the computer.* I am able to digitally hail a friends boat (with his MMSI already entered in my DSC phone directory) by simply selecting DSC call/Individual/Position Request/Send.* The radio automatically sends out a position request to my friends boat and, since he has his VHF set to auto respond to position requests, I immediately get a dot on my computer screen with his MMSI identifying his location.* Having the GPS connected to the VHF also means that if a DISTRESS call is made the position of the vessel is automatically included with the call so it takes the search out of Search and Rescue (the Coast Guard already knows who you are from the MMSI and where you are at from your GPS).*

DSC is a wonderful and powerful tool for marine communications.* The problem has been that few of us are using it to its full potential.* Read you manual and get an MMSI number.* If you only boat in US waters you can get a free MMSI from either BoatUS or the U.S. Power Squadron at http://www.boatus.com/mmsi/ *or http://www.usps4mmsi.com/. **If you travel outside of the US and contact foreign stations (meaning marinas, coast guards or other non-US boaters) then you are required by U.S. law to have both a stations license and a restricted radio-telephone operators license.* The last time I checked the station license was $205 (good for ten years) and the operators license was $55 (good for life).* You can get FCC licenses online through this website http://transition.fcc.gov/fees/welcome.html .

If you have recently purchased a used boat or a used VHF radio you should check the setup of the radio and make sure you don't still have the previous owners MMSI entered into the radio.* If you do, it is not going to do you any good.* Most radios allow you to reprogram and change a*MMSI two or three times before you need to send the radio back to the manufacturer for clearing and programming.* Better to do that then send out erroneous information like the guy is doing with the calls you are receiving.
Hope this helps.*

*


-- Edited by Steppen on Friday 8th of July 2011 08:37:49 AM

AllanY wrote:
It is the radio looking for GPS coordinades as part of the DSC system

Click to expand...

*Perhaps some radios do this but our ICOMs don't.* If there is no GPS position information being sent to the radio all that happens is that the radio display puts a row of question marks where the lat/long information would be.* There is no audible warning.

Woodsong wrote:
*my radio did not switch channels automatically as I understand DSC does when you are being "hailed" via DSC.

Click to expand...

*Could be someone with the mmsi # from the po calling him . When it beeps you have to hit the DSC for it to change channels sort of like answering a phone.

SD

Woodsong

I am not sure what part the MMSI number has to play in this however mine did it before I had the MMSI number and still does it after IF I don't have the GPS turned on
If the GPS is on it doesn't do it
My radio is a Navman DSC/VHF

Allan

Steppen wrote:
The MMSI of the caller is shown as 338108105 on your VHF display.*

Click to expand...

*Steppen---* While I am not the one with the original query I am very impressed with your answer.* I learned something myself from it.* Thanks much.

Tony--* If you do not already have an MMSI number and have it entered into your radio there is something you need to be aware of if you get a number and then*enter it.* And that is that most radios will give you two or three chances to enter an MMSI*number correctly and that's it.* If you make a mistake in entering, after your second mistake (or third with some manufacturers) the radio will no longer accept a number and you have to return the unit to the manufacturer to have it reset.* I'm told even the marine electronics shops can't reset a radio--- it has to go back to Icom or Standard Horizon or whoever.* This is spelled out in the manual of course, but it's something to be aware of before you begin to enter a number.

Brings up a question I've always wondered...if I sell the boat do I just leave my MMSI number in the radio, or enter another one or two to disable it? Neither seems a good option.

Keith asked:
if I sell the boat do I just leave my MMSI number in the radio, or enter another one or two to disable it?

Good question, if you have an FCC license then, when the boat sells, you are obliged to cancel/terminate the station license which in turn would cancel the MMSI.* FCC Station Licenses are not transferable between owners.* If you got your MMSI from BoatUS then go to http://www.boatus.com/mmsi/, log in and change your account to cancel the MMSI.* In either case the MMSI left in the radio will be invalid and won't report your name and address if the buyer plays with the radio.

Or, you could just enter a series of zeros into the radio and let the buyer plug in their new MMSI.

The best solution might be to work with the buyer of your boat and see that they get their own MMSI and then you could watch them reprogram the radios with their new number thus saving them from needing to send the radio back to the manufacturer.

I certainly would not leave an active MMSI in a radio I no longer control.

Saratoga Sue:*** WDD5605*** 367160830

*

Thanks all for the replies- really appreciate it, particularly Steppen!!
So reading through the VHF manual, it seems what I was receiving was an "all ships" alert from another boat. It must be accidental b/c certainly no emergencies reported. I am fairly certain the PO never registered an MMSI # so I am going to do that this week.

Steppen, I am very glad to hear that you have been able to connect your VHF to your laptop GPS. I am running a macbook for our GPS so will need to see how to convert the NMEA to a USB port as I don't have a serial port on my macbook.

Glad I started this thread as I have already learned a lot!

My pleasure sir!

The Keyspan USA-19HS USB to serial converter seems to be the most reliable on the market.* Most Belkin devices don't work with NMEA data.* The Keyspan works with both Windows and Mac operating systems.

Check out the Rose Point Coastal Explorer website for info on USB to serial converter hardware that works and doesn't work at (at least with their software)http://support.rosepointnav.com/support/hardware/USB

This is the Keyspan unit I have used




-- Edited by Steppen on Sunday 10th of July 2011 07:19:12 AM

Thanks Steppen! I hadn't thought of that. I'm licensed through FCC (matter of fact I think* my 10 years is about up) so I could handle it that way.

Tony, I thought you had one of these USB GPS Receiver pucks. http://www.amazon.com/USGlobalSat-BU-353-WaterProof-Enabled-Receiver/dp/B000V5TV22

It would send GPS signals to your laptop. Are you trying to get MMSI positioning data displayed on your laptop chart plotter?

Flywright,
yes, I am using a USB GPS for my macbook and running MacENC for charting. I wanted to display DSC locations on my charts and also allow my VHF to provide a position fix should I ever, God forbid, need to send my own distress call.