posted 05-15-2014 11:51 AM ET (US)        

The first test examined the behavior of an older but popular DSC radio, qualified to an initial specification for DSC. The older radio was used to send a DSC distress alert message. The most surprising result was that the message sent included only a coarse position for the vessel. This article appears at

DSC Distress Message Test
http://continuouswave.com/whaler/reference/DSC_DistressTest.html

The second test examined the behavior of a very recent model DSC radio, qualified to the most recent specification for DSC. This newer radio sent a DSC distress alert message with a position for the vessel to a resolution of 0.001-minute of latitude and longitude. This article appears at

DSC Distress Alert Message Test 2
http://continuouswave.com/whaler/reference/DSC_DistressTest2.html

The third article reports on my investigation into the format of the datagrams being sent from a DSC radio when it receives a call. These datagrams are not particularly well documented publicly, and this investigation attempts to discover more about them. Some insight into their structure is presented. This article appears at

Data Interface in Digital Selective Calling Class-D Radios
http://continuouswave.com/whaler/reference/DSC_Datagrams.html

The fourth article extends the communication system being tested to include a chart plotter receiving information from a DSC radio. The test found rather surprising inconsistencies in the interpretation of information across this link. The article appears at