"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.

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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