Digital Yacht is a substantial U.K.-based marine electronics manufacturer/distributor that is expanding to the United States in a timely manner, given its emphasis on Class B AIS. I'm testing its $899 AIT250 Class B, which—while being the same basic transponder that's marketed by Shine Micro, True Heading, and others—performs well, and is well accessorized. This Class B specific SPL250 antenna splitter is available as a $200 option to the AIT250, or for $359 alone, and it seems to work well. Sharing an antenna between a 25-watt fixed VHF and a 2-watt Class B AIS that both sometimes transmit is technically not trivial, but so far none of my test gear has smoked—even, as promised, if the splitter is inadvertently unpowered. Note, though, that sharing a coax cable does result in some degree of signal loss (which I'm trying to quantify), and that an SPL250 user will definitely forego AIS receive/transmit data when talking on VHF. All that said, the SPL250 will let you easily use an existing VHF stick for Class B AIS, and FM radio. Note that Digital Yacht has also shown a prototype Touch nav system that mixes Nobeltec charting, Class B AIS, WiFi, and e-mail with a touchscreen and voice commands all in a reasonably priced package.
This article originally appeared in the January 2009 issue of Power & Motoryacht magazine.