DSC polling for position

[srevir]

Reading ads for Standard Horizon GX 1500 I notice the position polling capability and the ability to display the polled vessel's position on a compatible plotter such as the SH 180

At first this sounded like a neat (and cheap ) alternative to radar but I dont think its that simple.

Its not clear but I think that this will only work if you know the MMSI of the target vessel.

So you dont get position info for all vessels within range without knowing their MMSI ???

Does anyone haave experience of using this function ?

Also any views on the SH kit

Thanks

 

[Allan]

I'm not sure of the function you mention but I have a H/H VHF from SH. It has been used and abused for a couple of years. The battery charge appears to last for ever and it never fails to be heard. Less than £70 and a great bit of kit.
Allan

 

[leomagill]

The position polling facility is not a look out system of any kind, it just means you can find your mate or as long as you accept the poll the CG can find you, most sets have a contact list to store mmsi numbers and you can set it to reply automatically to position polls from anyone on the contact list but without mmsi's it's useless.
If you have a H/H dsc you could use it as a remote security feature I suppose to check how far away your boat is.

 

[wotayottie]

often wondered what it was there for - its a facility in lots if not all dsc sets.

suppose it could be used in racing to find out where an opponent is

 

[Phoenix of Hamble]

but it requires them to accept a request for position, or to set their DSC radio to automatically accept..... I can't see many racers doing that!

 

[MarieK]

This works well in conjunction with AIS, you get the MMSI of any shipping in the area from your AIS receiver and can then contact the ship if required using DSC. Does away with calling "large red ship off my port bow"

Another advantage is that requesting the position using DSC polling sets off an alarm in the bridge of the ship requiring them to reply. If a ship is bearing down on you at least you know there is someone there and awake!

Ryan

 

[neale]

I have used this function on Raymarine kit. It's great when cruising in company but out of sight of each other. You have the other boats MMSI no in your list, you send them a position request, they acknowledge and reply and they pop up as a waypoint on the plotter. Some sets can be programmed to auto reply to a position request.

 

[Anonymous]

[ QUOTE ]
This works well in conjunction with AIS, you get the MMSI of any shipping in the area from your AIS receiver and can then contact the ship if required using DSC. Does away with calling "large red ship off my port bow"


[/ QUOTE ]That's an interesting point. In busier areas we often hear ships calling other ships on Ch16 by name rather than using the DSC. Same applies to the NATO operation Active Endeavour, where they use Ch16 constantly to call ships that they clearly have on AIS (they have callsign, name, position, speed,...) and I often wonder why they don't call on DSC.

It could be that all I am seeing is the 'tip of the iceberg' and that most calling is via DSC but given the number of Ch16 calls I rather suspect that commercial vessels don't respond well to DSC.

Is there a commercial user here who can tell us?

 

[RAI]

I've got the SH GX 1500 and SH 300i combination. They work well together. The feature your are talking about relies on a buddy-buddy agreement, both sets have to have each others' MMSI then they can track each other. OK for cruising in groups, not good for AIS.

A feature that I like with the combination is that the position transmitted in DSC MAYDAY alerts can be displayed on the chartplotter, so it's easy to see if they are in range of your own vessel.

The SH chart plotter will accept normal AIS input and display AIS targets. It will also accept a SITEX radar scanner input for radar overlay.

 

[RAI]

I suspect just calling on Ch16 is a whole lot quicker than entering an MMSI number. It also avoids annoying the other OOW with a DSC call and its alarm tone, he'll respond just as fast to his own ship's name.

 

[Anonymous]

[ QUOTE ]
I suspect just calling on Ch16 is a whole lot quicker than entering an MMSI number. It also avoids annoying the other OOW with a DSC call and its alarm tone, he'll respond just as fast to his own ship's name.

[/ QUOTE ]Yes, it is a very intrusive system. Totally unsuitable for cruising yachts with husband/wife crew who tend to be busy or one of them asleep. It can't be that convenient on a ship's bridge, either.