DSC VHF distress call position on AIS?

[haydude]

Having an AIS receiver, would that receive a distress call from a DSC VHF and plot the position?

Assuming that the vessel/individual sending the DSC distress call does not have an AIS transponder/transmitter, just the DSC VHF.

 

[Twister_Ken]

Having an AIS receiver, would that receive a distress call from a DSC VHF and plot the position?

Assuming that the vessel/individual sending the DSC distress call does not have an AIS transponder/transmitter, just the DSC VHF.

No. The AIS does not receive DSC calls, your VHF-DSC radio does. If the radio and the AIS receiver are compatible and linked by NMEA or a proprietary network, the position of the mayday vessel may show on the AIS screen (or plotter, if you have one wired into the system).

 

[prv]

Yep - AIS has very little to do with VHF DSC.

A VHF and plotter from the same company *may* be able to talk to each other so that when the VHF hears the distress transmission it is plotted on the plotter, but as far as I know there's no inter-manufacturer standard for this yet.

Pete

 

[haydude]

Yep - AIS has very little to do with VHF DSC.

Well not quite, because an AIS transponder can send a DSC VHF distress call on ch. 70 just by pressing a button. Hence my question if it also could receive and plot the position sent by a DSC VHF distress call.

 

[prv]

Well not quite, because an AIS transponder can send a DSC VHF distress call on ch. 70 just by pressing a button.

Oh, ok. Surprises me slightly as it's not an AIS function, but since there's a VHF transmitter in there anyway I suppose a manufacturer might as well include the feature. I hadn't noticed such a thing, but I've only really looked at AIS receivers as I'm not interested in transmitting.

Pete

 

[ditchcrawler]

The Standard Horizon Gx2100e withbuilt in AIS shows the name of the ship sending DSC and when the channel knob is rotated shows the position, distance and bearing of the ship sending the DSC.You can then press the waypoint key to enter it as a waypoint and switch to the waypoint screen to steer towards it.

 

[haydude]

The Standard Horizon Gx2100e withbuilt in AIS shows the name of the ship sending DSC and when the channel knob is rotated shows the position, distance and bearing of the ship sending the DSC.You can then press the waypoint key to enter it as a waypoint and switch to the waypoint screen to steer towards it.

That is cool! Too bad I do not have SH VHF!

 

[RestlessL]

I am also surprised that an AIS transponder can send and receive DCS distress calls. My Comar CSB200 certainly cannot, but I will concede that some may do so.

However, I would expect a VHF DSC radio to be able to display a distress position if connected to a chart-plotter. To do so you need a two-way NMEA connection between the radio and the chart-plotter. Most of the directions given on this forum for connecting GPS to DSC radios only suggest a one-way connection (GPS NMEA-out to radio NMEA-in), but you can also connect the radio NMEA-out to the chartplotter NMEA-in.

This is the connection I have between my SH VM3500E radio and Garmin 3005 chartplotter. On receipt of a DSC distress call the chartplotter will sound an alarm and set a waypoint for the origin of the distress call.

It doesn't stop there. I also have a SH HX851E DSC handheld. I can send a DSC position request to this handheld from the ship's radio, and get an automatic response, which is also passed on to the Garmin chartplotter and a waypoint set.

John

 

[Bilgediver]

Well not quite, because an AIS transponder can send a DSC VHF distress call on ch. 70 just by pressing a button. Hence my question if it also could receive and plot the position sent by a DSC VHF distress call.

Perhaps you could enlighten us to which AIS can do this other than those which form part of a VHF transceiver!

 

[pvb]

Well not quite, because an AIS transponder can send a DSC VHF distress call on ch. 70 just by pressing a button. Hence my question if it also could receive and plot the position sent by a DSC VHF distress call.

I didn't know that! Which transponder does that?

Some transponders, when linked to a compatible VHF DSC radio, can trigger a voice call to an AIS target, but that's rather different from what you're saying.

 

[richardbrennan]

I have an Icom 505 radio and a Garmin 5012 plotter. The radio is obviously getting the position from the plotter via NMEA but, having had the opportunity to get somebody to call me using DSC today, the Icom does not seem to be talking to the plotter in spite of the radio NMEA out being wired to one of the plotters NMEA in ports. Obviously the first step is to check the wiring, which I did not have time to do today, but do I have to do anything else to get the units to talk to each other?

 

[RestlessL]

I have an Icom 505 radio and a Garmin 5012 plotter. The radio is obviously getting the position from the plotter via NMEA but, having had the opportunity to get somebody to call me using DSC today, the Icom does not seem to be talking to the plotter in spite of the radio NMEA out being wired to one of the plotters NMEA in ports. Obviously the first step is to check the wiring, which I did not have time to do today, but do I have to do anything else to get the units to talk to each other?

Just calling using DSC does not send the position to the chart plotter - the other party has to send a DSC position report (or respond to a DSC position request).

J

 

[aluijten]

For the ICOM 505 you can set this to autorespond. If you receive a positionrequest it will respond without user interaction. Also the 505 does send out any positions it receives via DSC (via NMEA). It could be you need to setup the plotter to handle those request. The plotter might also not be capable of handeling those position reports.

 

[richardbrennan]

I tried requesting a position report and it comes back on the radio but still not on the plotter. The plotter handook is c**p, (I think it was written by a dyslexic Korean), but my undersdtanding is that it should show DSC position reports, it also shows what is being received via NMEA and the DSC is showing no information. As I said, the wiring is probably the place to start but I do wonder if I need to turn anything on in the radio?

 

[aluijten]

Can't remember if you need to setup the ICOM as well. I didn't think so. Did yo also verify the NMEA port speed on the plotter? The ICOM works at the standard 4800. It may be that your plotter expects 19k2. The other point may be that (if memory serves me) the ICOM uses a grounded signal-return line (NMEA -). This can sometimes give you trouble as well. Finally there may be a software version issue on your specific ICOM. You could ask your local ICOM dealer/distributor if a minimal software version is required. From what I've understood from the Dutch distributor is that the M505 is software upgradable by the dealer/distributor. This is also required if you want it to play nicely with their upcoming AIS transceiver.

 

[richardbrennan]

You can vary the port speed on the plotter but they are all set to standard and until I look at the wiring I am unsure which port the radio is feeding, (my son wired it up). You are right about the feed from the radio being a single return line, but this is the same for the NMEA input and that is working OK.

 

[Twister_Ken]

My Icom 505 is supposed to relay a DSC distress call position to my Garmin plotter. Dunno if it works, haven't had a DSC mayday when I've been aboard to look.

 

[Georgio]

The Vespa Watchmate Transponder I have just installed has the facility to send a Mayday, however I'm not sure if that is an AIS only mayday or a DSC mayday, I will have to read the instructions to find out but there is a distinction between the two as these are two different systems.

Interestingly you can now also buy AIS SART's if you wish, that was a new one one me a few days ago.