DSC Basics

[Caribsailors]

Great Thread!! Thank you

[Sandero]

Can we hear some recommendations for fixed mount VHFs w/ DSC... (I'm going to replace my old VHF)?????

What features do you like about it?

Does it have an internal GPS?

What is the current draw?

etc...

[Dockhead]

Originally Posted by nigel1

GMDSS which includes use of DSC was introduced way back in 1992, with final implementation in 1999. As Dockhead pointed out, the use of DSC has not been readily taken up for some reason, and this is true amongst both leisure craft and commercial vessels.
As pointed out, one purpose of DSC on VHF was to cut out unnecessary traffic on CH16, and the same with 2182kHz on SSB, which has led to the removal of the 2182 watch alarm from ships, and the shore side 2182 watchkeeping in many countries.

I have no idea why VHF DSC is underused, one theory on commercial ships is due to the proliferation of alarms on the bridge, radar alarms, AIS alarms, engine alarms etc, so that when a DSC alarm sounds, the watchkeeper may look at the message, and if it is not Distress, just hit the cancel button.

I try and use DSC, all my calls to Coastguard are initiated with DSC, and I have some luck with contacting other ships and boats by DSC, but not many.

Give it another 20 years and it may catch on.

Same as my experience. I don't think I've ever once raised the bridge of a commercial ship with DSC, although I regularly attempt it. Disappointing, as it would so much facilitate communications.

The Coast Guard, by way of contrast, are perfectly trained in it, and respond snappily. They are happy to get a DSC call rather than someone jabbering on 16, and often say so.

The only time I ever received a DSC call from anyone other than a friend or crewman was in Eastern Finnish water, where the border with Russia runs East-West for a ways where the Russians retained the outer islands.

I was tacking upwind against perverse Easterly winds to get into Kotka, the last decent port in Finland. It was last year (well technically year before last already -- 2014) with my old baggy sails, so my tacks were fairly wide. I took a long tack out to sea and suddenly -- a non-emergency DSC call comes in. From the Finnish Coast Guard. They were watching me on AIS and saw me closing on the island of Gogland (Suursaari I think it's called in Finnish), which is a Russian military island, apparently armed to the teeth. They asked me politely where I thought I was going. When I explained I was under sail and would tack soon, they laughed for a long time and wished me a good passage.

P.S. -- memory error -- there was another time -- a DSC call from the Estonian Coast Guard -- warning me that there were rocks in my path. Also 2014, before I knew to stay in the fairways in Baltic waters.

[puffcard]

The main reason for DSC is the safety. With activation of a single button the VHF automatically sends a distress call to all DSC equipped ships, boats and shore stations in range. The call automatically includes:
Your identity; which is why the handheld should have the same MMSI in case you abandon ship.
Your position (if a GPS receiver is connected); and
the nature of your distress (this can also be edited, if needed).

The call will be automatically repeated until stopped by an acknowledgment message.

My biggest concern, is many times I send out DSC calls and never get a response. It makes we wonder what kind of response would I get with a DSC Distress Call? Would it be much better to use a standard VHF MAYDAY?

Couple other points,
If going outside the US, the ship needs a station license and the MMSI will be assigned by the FCC...not the one from BoatUS. $215

You are also required to have a Restricted Radio Operator Permit. Lifetime $65

This includes the Bahamas and Bermuda.

[colemj]

Originally Posted by Sandero

Can we hear some recommendations for fixed mount VHFs w/ DSC... (I'm going to replace my old VHF)?????

What features do you like about it?

Does it have an internal GPS?

What is the current draw?

etc...

I highly recommend Standard Horizon for the sole fact that their user interface is the most intuitive and easy to use. Icom is a horrible mess in this regard. I don't have experience with other brands.

They will all have pretty much the same feature set, the difference will be the ease of accessing those features without going to a manual or burying yourself deep into layers of menus.

Some come with internal GPS - I recommend those.

Current draw is inconsequential - they will all draw essentially the same, and DSC doesn't add to that.

Mark

[monte]

Our raymarine is horrible to use as well. A lot of knob twiddling to get through menus and tiny writing on the screen. I've recieved a couple of DSC calls but accidentally hung up by pressing the wrong button. Maybe if I used it more often it would be more intuitive.
Would the range of position polling be similar to AIS range? I guess it could be handy when sailing in company with non AIS transmitting yachts, but would probably still require imputing the coordinates into a chart program. Maybe some have an auto plot feature to send the position directly to the plotter?

[Sandero]

Thanks Mark...

I have a Horizon hand held w/ DSC... when I get a new one can I program the hand held MMSI into that one? And I am good to go?

[colemj]

If your radio DSC output is wired to your plotter, the positions will show up there automatically.

Mark

[colemj]

Originally Posted by Sandero

Thanks Mark...

I have a Horizon hand held w/ DSC... when I get a new one can I program the hand held MMSI into that one? And I am good to go?

Yes, if it is registered with your ship.

Mark

[monte]

Originally Posted by Sandero

Can we hear some recommendations for fixed mount VHFs w/ DSC... (I'm going to replace my old VHF)?????

What features do you like about it?

Does it have an internal GPS?

What is the current draw?

etc...

I'm not sure where you are but in Europe the navicom has some interesting specs that include mob functions and wireless remote and AIS. I haven't used one but I haven't seen any other vhfs with mob built in. I'm. It sure how it works, maybe like the raymarine system with a separate transmitter. I guess some discussion on DSC MOB devices can be included here as well.

[davido]

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I use the following setup and process to use the USCG automated response to test my VHF DSC functionality.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

VHF DSC TESTING

Test transmissions on VHF DSC calling channel 70 should be made to another VHF DSC radio by using a routine individual call to their Maritime Mobile Service Identity (MMSI).

For VHF DSC radios equipped with the Test Call feature, test transmissions should be made to the US Coast Guard MMSI 003669999 to receive an automated VHF DSC test response. You must use the “Test Call” category of your radio because “Individual” category calls to this address will not receive an automated response. For older radios not having a test call capability, testing can only be performed by using a routine individual call to their Maritime Mobile Service Indentity (MMSI).

UNDER NO CIRCUMSTANCES SHALL A DSC DISTRESS ALERT BE SENT TO TEST YOUR RADIO. IT IS A VIOLATION OF THE RULES AND CAN RESULT IN HEAVY FINES.

Please consult your owner's manual for the proper operation.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
It takes a couple minutes to program the USCG MMSI into the VHF memory and usually less than a minute to test the functionality. I use it whenever I make any change to the VHF or NMEA wiring and prior to longer offshore voyages to verify the system functionality.

I agree with other postings stating that the non- emergency DSC is very under used. While the setup and use is not terribly complex, it is not dirt simple. I suspect many don't bother with trying to understand it, set it up, and use it because their peers have not bothered to understand it, set it up, and use it.

For what it is worth, I have an ICOM M504A, a class B DSC radio.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[nigel1]

I installed the Icom M423 last year, and found it easy to use, very intuitive.

[nigel1]

One thing to be aware of with DSC radio's is the Auto Acknowledgement function.
When another boat or shore station sends a DSC call, it will often include the working channel to be used for the message.
Some DSC radio's have a feature that will automatically change to that working channel, if you are unaware of this, you may think you are keeping a listening watch on 16, but another station may have caused your radio to switch to another channel.
It's worth checking the settings on your own radio.
Most authorities recommend that this setting should be disabled if you only have the one VHF DSC.

[The Smokester]

I have the B&G V50 ship's vhf. Integrates with Zeus 2 chart plotter. Has wireless, rechargeble remote mics. 200mA standby current. AIS receiver built in (I have a separate AIS transponder). Requires external GPS.

Also an Icon M92D handheld with internal GPS. Programmed with ship's mmsi no. Small screen. This radio works fine but apparently has only one receiver, not a second receiver devoted to the DSC channel 70, and so does not meet USA FCC standards and has been discontinued.

A Standard Horizon HX870 portable programmed with its own mmsi no. I use this for crewing on other boats. Large screen. Dual receivers (FCC compliant). Has a water-activated strobe which, unfortunately, has triggered on night watch when conditions are sporty, and so this feature has been deactivated on my unit. This is a good unit.

I have never received a legitimate dsc call!

Good thread.

[svGenesis]

Originally Posted by cal40john

How about this-

Can You Hear Me?

Very nice link...Explains it all!

I'm surprised it didn't come up in the ASA104 class i recently did as they covered the VHF and other safety functions very well.