AIS reception aboard homeward bound Bliss on 08-31-08.

Mel - May 11, 2009

At 12:25 Bliss is in the center of the radar range rings heading 198°T and position as indicated on the right side of the print screen pasted below.  Although it has nothing to do with AIS the radar range is set for 36 miles to the outer green ring as indicated in the upper left corner of the chart image.  Lots of traffic today with the Algorail placed NNE with range at say 45 miles and the 1000’ – St. Clair almost under the Blue Water Bridge with range at say 38 miles.  The nearby Algomarine and the Agawa Canyon are crossing to and from Goderich.

The Automated Information System (AIS) is provided by international mandate thru a special VHF signal from coast guard, commercial, and other types of ships.  An AIS receiver is required with its input from a VHF antenna that can be shared with your VHF radio thru a special automatic splitter that protects the receiver from VHF transmission.  The receiver output in my case is simple RS232 that Nobeltec accepts as an input.  Aside from displaying the vessel the 20 or so fields of information received from each vessel can be viewed in Nobeltec by clicking on the button with the yellow triangle near the upper right corner and selecting the ship from the list of those in view.  The closest one is the default.  At a closer range the vessel appears with an outline dimensionally scaled on the chart.  With the radar turned on the outline is filled in with red thus combining two technologies.  Also the user can define a collision threat range which triggers an alarm with the calculated min range and time to go.  Aside from knowing who’s out there this is tons of fun!