"luc" wrote in message
oups.com...
What is the difference between AIS and DSC? They seem very similar,
use VHF etc. Also, is it possible to test a VHF antenna for optimal
performance?

thanks,

Luc


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.

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).

DSC also has a "panic button" feature that you can push and the radio
automatically broadcasts your GPS position and the fact that you have an
emergency.

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

Here is a link to a popular AIS receiver:

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

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
http://www.sailmag.com/05feellison.qrk.pdf
http://www.amcom.nl/marine/icom_ic_m421.htm