DSC

[estarzinger]

I have just been going over and improving my DSC installation and have two questions:

1. What useful DSC numbers should I put in the radio's Phone book?

2. This radio (a 10 year old ICOM) has a nema out, which I had not previously hooked to the plotter but just now have. I presume its supposed to show the location of an emergency call. My question is there anyway I can test this works/is hooked up correctly?

Thanks

[goboatingnow]

how about

306156000 the MMSI of Super servant 3 the Dockwise ship, just in case you get a bit tired.
273132400 Yamal, a Russian Artic Icebreaker, what with the last few winters you never know.


PS:These are real MMSIs of those Ships
Dave

[osirissail]

DSC is the marine version of SELCAL for aviation. It is - ignoring the emergency functions for a moment - a "speed dial" type convenience.
- - You gather from other friendly boats their MMSI numbers and enter them into the DSC library with a short "word" to identify the entry - like "Bob" or "Joan" or a short version of the boat's name.
- - When you want to "call" them you find a VHF channel that is not in use or reserved and set your DSC radio for that channel. Then activate the DSC call function, select the "word/name" and again press the DSC call button. Your radio will automatically call the other selected boat's DSC radio and if they have their radio turned on, re-channelize their radio to your operating channel along with sound a "telephone" type ringing noise from their radio. When they "answer the phone" by depressing their mic button, you are "live" and can carry on your conversation.
- - This system bypasses all the needs to wait for and getting on a net to try to contact your friends. It operates similar to a telephone "speed-dial" in that you select their name and press a button and everything else is automatic (as described above).
- - As to entering other MMSI's such as USCG and others you need to get their MMSI number which they may or may not make available to the public.
- - Of course when you first get the radio you need to "program" in your own MMSI number which can be found on your "Ships Radio Station Authorization" (radio license) in the 10th block down counting from left to right then down. It is labeled "Ship Station Identity". If that block is blank then you need to get a MMSI from the FCC or use a service like BoatUS to get one.
- - Likewise your friends need to locate their own MMSI from their ship radio license and exchange that information with you.
- - As to your question #2, you can download a free NMEA reader like: NMEALOGR from a Google Search and then install the program and connect the NMEA output from your radio to your computer. It will then display what is coming out of the radio's NMEA - if anything. You can also download free GPS reader like VisualGPS and that will probably also display the NMEA sentences coming from the radio. Additionally the GPS NMEA readers can be used to see if your GPS is functioning and outputing data.

[estarzinger]

Originally Posted by osirissail

I have done all the basics - my mmsi programed in and those of my local friends. and my gps is functioning and is outputting data to the radio - I can see the lat/long and time on the radio screen.

- - As to entering other MMSI's such as USCG and others you need to get their MMSI number which they may or may not make available to the public.

OK, that was the sort of thing I was thinking about. I had expected that there would be a 'standard' list of the most useful/important MMSI numbers that one might want to pre-program. But I guess there is not.

- - As to your question #2, you can download a free NMEA reader like: NMEALOGR from a Google Search and then install the program and connect the NMEA output from your radio to your computer. It will then display what is coming out of the radio's NMEA - if anything.

Well the 'if anything' is the problem I was wondering about. I presume since I am not getting/don't have an emergency call that the radio is not outputting any sort of waypoint via nema to the plotter. SO what I think I need is some sort of way to input an emergency call to the radio to then see if it outputs a nema waypoint.

.....

[osirissail]

That last blue statement is a bit unclear. If your radio receives DSC calls from your friends then most probably the radio is functional in all modes.
- - The problem with "waiting" for a DSC emergency call to see if your radio/plotter interconnect is functioning - that could be a life-time long wait. Very few people have the foggiest idea about how DSC works and how its emergency functions work. Which is a shame but real life.
- - Interconnecting to a plotter has several big questions. Providing there is nothing in the radio manual that states what is put out down the NMEA line, you would need one of the utility NMEA/GPS programs to actually see what "sentences" are being output by the radio. Then you would have to research the Plotter manual to see what NMEA sentences it will accept and display. There is a whole universe of NMEA sentences and various plotters or computer programs only accept some of them not all of them.
- - As to doing a live test, you would have to get a dummy antenna for the radio to preclude actually broadcasting a distress call and then send a DSC distress call and see what shows up on the Utility program and/or the Plotter.
- - As to the MMSI numbers for the USCG or other stations, each individual station in use has it own MMSI number. And with the effective range of most VHF radios being from a few miles to as much as 50 nm you would have to program in a long list of numbers - unless you never planned on leaving your local waters by more than 50 nm.

[Wotname]

Originally Posted by osirissail

.......
- - As to doing a live test, you would have to get a dummy antenna for the radio to preclude actually broadcasting a distress call and then send a DSC distress call and see what shows up on the Utility program and/or the Plotter.
- - .......

As for doing a "live" test, I suppose you could borrow another VHF (DSC) unit, rig it up temporarily beside your radio and either
1. connect the two antenna ports together suitable with a suitable RF attenuator in series
or
2. connect a 50 ohm dummy RF load to the antenna connector on the borrowed radio and say wrap a turn or two of wire around it and then connect that to your antenna connector

Then hit the distress button on the borrowed radio. Your radio will receive it and process it accordingly.

But don't try this if you are moored right outside your local CG unit, you will be surprised how far you can actually transmit without an antenna.

[goboatingnow]

- - As to entering other MMSI's such as USCG and others you need to get their MMSI number which they may or may not make available to the public.

all properly issued ( ie not BoatUS) MMSI's teh world over are public information and maintained in the ITU database, thats searchable on the net or you can buy the big ITU directories, ( search by callsign, name or MMSI)

- - This system bypasses all the needs to wait for and getting on a net to try to contact your friends. It operates similar to a telephone "speed-dial" in that you select their name and press a button and everything else is automatic (as described above).

DSC isnt really like SELCALL, as thats typically used in a trunked radio system that DSC is not.

DSC does not do free channel arbitration nor does bypass the need to wait for getting on the net. ( radio),

Dave

[Wotname]

Originally Posted by goboatingnow

......
DSC isnt really like SELCALL, as thats typically used in a trunked radio system that DSC is not.
.....

I think Osirissail suggested it was "like selcal for aviation", rather than selcal as used in a trunked radio system.
To my mind, that is reasonable analogy.

[Pyxis156]

Evans,

I found this link to be helpful in setting up some emergency MMSI numbers in my VHF. It lists the MMSI for each USCG Sector/Group in the US as well as the "global" MMSI for all USCG stations in the US. It also lists the international MMSI number designated for all coast stations.

Hope this helps,

Steve

[Auspicious]

Evans -

VHF or HF? Which radio? The sentences your radio generates on reception of a DSC depends on the radio, and what your chart plotter does about it depends on the plotter.

On my VHF I keep the nearest USCG or international RCC. I have everything within 5000 miles on my HF radio.

The MMSI of RCCs and USCG sector and station offices is publicly available information. Google uscg mmsi sector sectorname and you'll get a homeport.uscg.mil address near the top of the page. All the RCCs I've looked at show up similarly (I have Bermuda in my VHF and HF radios).

sail fast, dave

[estarzinger]

Afriend who has been a big DSC early adaptor suggested the following from his phone book:

MMSI Numbers for your VHF Radio’s Directory
The following numbers should be programmed into your VHF radio:
USCG Ships/Vessels (all within range) 003669999
USCG Stations (all within range) 036699999
SeaTow 033801999
Tow Boat US 033804000

He thinks my radio/plotter will show a waypoint for any call, not just emergency calls. If thats true I can test the 'radio out to plotter connection' by just getting a dock nabour to dsc me. I will give that a try and see. But if it does not put a waypoint on the plotter I will not know if I have the connection wrond or if the radio only does it for emergency calls - I guess in that case I will have to call ICOM and ask, but given its now an 'oboslete' radio I don't know if they will even be able to answer.

Originally Posted by Auspicious

VHF or HF? Which radio?

ICOM VHF, and Furuno plotter. The radio has a nema out cable and the plotter has a nema in - and its manual says it will plot waypoints from ais and dsc coming in from nema. That's all I know. I am pretty sure I have the wires right, both manuals show which are 'in/out' - it's only a two wire connection so I have at worst a 50/50 chance

[Wotname]

What model Icom VHF is it as I have some old manuals?

[goboatingnow]

Dsc routine calls do not contain position information. Hence plotters can't waypoint them.

Dave

[estarzinger]

Originally Posted by Wotname

What model Icom VHF is it as I have some old manuals?

I think old (before the class d model) M504. I will check tomorrow.

Originally Posted by goboatingnow

Dsc routine calls do not contain position information. Hence plotters can't waypoint them.

hmmm . . . interesting but odd . . . my 'dsc friend' has a dsc handheld and he says his plotter will show the position of the handheld.

Here's what he said " . . . a DSC enabled Handheld VHF radio that I have loaded with a Boat/US asigned MMSI registered to "Sam's AVON". This has given me a way to check out the DSC functions of the installed radio and the plotter using Position Requests and both Individual and Group Calling features."

[goboatingnow]

The key word is " position requests ". This is a specific feature that requests a DSC response from the receiver to send it's position. It has to be user replied to.

Note " position request" is not a GMDSS feature and may not be present on all class D DSC radios.

As I said if you generate a standard " routine" DSC call your position information is not relayed automatically. This is only done on DSC Distress and Urgency calls.

Dave