Can any one explain to me the use of a DSC controller. Are they just used to send a distress signal to the coast guard etc. Iam thinking that they act as a kind of EPRB. Would this be correct.
ICS Electronics have a good introduction to GMDSS and DSC on their web site.
Another interesteing site, although a bit more technical, is www.gmdss.com.au -- it's Australian, but that shouldn't matter as it's a worldwide standard.
Yes - one use is in an emergency.
You can hit the red distress button and if its connected to your GPS it will transmit a "digital MAYDAY" to the CG and other ships within VHF range.
You can also call individual boats by calling their MMSI number - a bit like a phone number - this in instead of calling them on Ch16 and then moving to a working channel.
The radio can store MMSI numbers just like your mobile phone so you don't have to remember them all
These days commercial ships do not have to keap a listening watch on Ch16 - but they do have to have a DSC radio fitted. So the only way you might get there attention is by sending an "ALL Ships Call" when they are heading straight for you and your engines just konked out
Out of interest - I was trying to call the CG on Ch16 to inform him of my safe return but for some reason I wasn't transmitting - I could hear other traffic, but nobody responded to my call. I then called the CG using the DSC and their MMSI number and after a couple of secs I recieved a DSC Acknowledgement.
I still couldn't talk to them via VHF so I used a mobile to inform them of my safe return.
My point is - VHF audio wasn't working - but DSC was sent and recieved so I could have sent a distress message.
(I'm still not sure what was wrong - I wonder if it was on low power - its worked fine since)