What is the DSC term used with marine VHFs?

RB wrote:
What is the DSC term used with marine VHFs?



Try this: http://boating.ncf.ca/vhfdsc.html

--
Kees

Good. Thanks.

Very good opinion. I do not understand why Garmin, Raymarine and Icom,
for example continue to invest in DSC; the "new" DSC Position Report
feature of Garmin GpsMap 276C for example, wich demandas a VHF Radio
with NMEA IN and OUT, is ridiculous. These manufacturers should
instead take attention to AIS insted this "half-assed" DSC technology.


Pascal

Larry and Pascal:

Isn't the momentum for DSC and GMDSS being driven by European
requirements? My understanding is that implementation by the UK and
other European coast guard stations is farther along than in the US.
Manufacturers tend to build to meet the market's most stringent
requirements.

Chuck

Pascal wrote:
Very good opinion. I do not understand why Garmin, Raymarine and Icom,
for example continue to invest in DSC; the "new" DSC Position Report
feature of Garmin GpsMap 276C for example, wich demandas a VHF Radio
with NMEA IN and OUT, is ridiculous. These manufacturers should
instead take attention to AIS insted this "half-assed" DSC technology.


Pascal

"Pascal" wrote in message
oups.com...
Very good opinion. I do not understand why Garmin, Raymarine and Icom,
for example continue to invest in DSC; the "new" DSC Position Report
feature of Garmin GpsMap 276C for example, wich demandas a VHF Radio
with NMEA IN and OUT, is ridiculous. These manufacturers should
instead take attention to AIS insted this "half-assed" DSC technology.


Pascal


DSC and AIS are two different systems to meet two different needs. AIS lets
you track all the ships around you for collision avoidance and DSC lets you
"select" which ship to call on the radio. When the two systems are merged
the AIS display will let you pick the ship you want to talk to and call only
him using DSC. Everyone else will not have to listen to your conversation.

DSC and AIS use almost exactly the same digital modulation/demodulation
technology so the R&D money spend on either system to adapt existing analog
radio designs to digital modulation benefits the other.

-------------
Here is more info concerning AIS and DSC:

AIS and DSC are the new technologies for receiving
position reports of other boats in your vicinity.

Digital Selective Calling (DSC) is on marine VHF channel 70 (156.525 MHz)
Automatic Identification System (AIS) broadcasts are on two VHF marine
channels 87 (161.975 MHz) & channel 88 (162.025 MHz).


Here is a link to a popular AIS receiver:


http://www.nasamarine.com/AIS/AISENGINE.html


Here are some web pages that further describe AIS and DSC


http://www.navcen.uscg.gov/marcomms/gmdss/dsc.htm
http://www.navcen.uscg.gov/enav/ais/default.htm
http://www.sailmag.com/05feellison.qrk.pdf
http://www.amcom.nl/marine/icom_ic_m421.htm


If you want to use the sound card to decode and display AIS data on your
laptop see this web page:


http://www.coaa.co.uk/shipplotter.htm


Here are a few more interesting links:


http://www.xmradio.com/weather/
http://www.xmradio.com/weather/av_subscription_pkg.pdf
http://www.garmin.com/products/gpsmap376c/


http://www.nasamarine.com/press/pdfs/sx35.PDF
http://www.nasamarine.com/press/pdfs/sx35pract.PDF
http://www.nasamarine.com/press/press.html

chuck wrote:
Larry and Pascal:

Isn't the momentum for DSC and GMDSS being driven by European
requirements? My understanding is that implementation by the UK and
other European coast guard stations is farther along than in the US.

True, in Europe all coastguard stations have the equipment, and so do
all IMO registered ships. They are checked when they get to port.

Manufacturers tend to build to meet the market's most stringent
requirements.

The IMO is a worldwide organization, and it has mandated GMDSS, of which
DSC is a part. As of February 2005 no coastguard in the world nor any
vessel is _obliged_ to listen to Channel 16. They may do so however, and
this is done even in Europe.

From the UK MCA website:
http://www.mcga.gov.uk/c4mca/mcga-gu...comms_code.htm

"While the United Kingdom Coastguard will continue coverage of VHF
Channel 16 for the foreseeable future, from 1 February 2005, the
Coastguard watch on Channel 16 will be downgraded from a dedicated
headset watch to a loudspeaker watch. Also, from this date, ships that
are currently obliged to keep a listening watch on Channel 16 where
practicable, will no longer be obliged to do so."

And the Dutch coastguard says:
http://www.kustwacht.nl/Engels/Newsl...37E%20LW16.pdf

"It is therefore that the Directorate-General Freight Transport of the
Ministry of Transport and Public Works decided to continue the radio
watch on VHF channel 16 in The Netherlands, for the time being for an
unlimited period, after February 1st 2005. The decision of other
countries in this matter is unknown.
In spite of the above-mentioned decision The Netherlands Coastguard
maintains its advice to seagoing yachtsmen to change over to GMDSS
equipment. It is in their best interest to initiate alerts on VHF DSC
channel 70 whenever the circumstances require doing so. Only in this way
one stands a very good chance to be “heard”."

--
Kees

Kees Verruijt wrote:
chuck wrote:

Larry and Pascal:

Isn't the momentum for DSC and GMDSS being driven by European
requirements? My understanding is that implementation by the UK and
other European coast guard stations is farther along than in the US.


In follow-up, read this: http://www.navcen.uscg.gov/marcomms/gmdss/dsc.htm

"The USCG plan to implement GMDSS Sea Area A1 is one element of the USCG
National Distress and Response System Modernization Project, now called
"Rescue 21", which replaces the whole USCG VHF distress system. On 24
September 2002, Secretary of Transportation Norman Mineta announced the
award of this $612 million contract to General Dynamics Corp.

Until this system is installed, the Coast Guard cannot reliably receive
VHF DSC distress calls."

Guess 3 1/2 years is not enough time for the US government and General
Dynamics to install radio transmitters with DSC ...

--
Kees

"Ted" wrote in
. net:

When the two systems are merged
the AIS display will let you pick the ship you want to talk to and
call only him using DSC. Everyone else will not have to listen to
your conversation.


That's true if you stay on Channel 70 and don't listen to 16 or the other
CB channels...68, 69, 71, 72, 10, 12, 13....(c;

DSC is required in all new console mount VHF radios being type
certified.

Garmin made almost no investment -- just a few lines of code. All the
HW was already there. They did it because Standard Horizon had it
and was pusing it it. A fair number of radios have NMEA IN and OUT
(mine does, and it's several years old).


"Pascal" wrote in message oups.com...
Very good opinion. I do not understand why Garmin, Raymarine and Icom,
for example continue to invest in DSC; the "new" DSC Position Report
feature of Garmin GpsMap 276C for example, wich demandas a VHF Radio
with NMEA IN and OUT, is ridiculous. These manufacturers should
instead take attention to AIS insted this "half-assed" DSC technology.


Pascal