By Ben Ellison
Plug Prayers Answered
Should I get a full AIS transponder or just a listener? X.G, via e-mail
However, that second “if” is a biggie. Currently available Class A AIS units cost upward of $4,000 and can entail serious additional installation expense. Besides antennas and power, they need NMEA 0183 input from GPS, electronic compass, and speed transducer, any one of which may lack the horsepower to send data to yet another device. Then there’s the special, fast 0183 output to the various radars, plotters, and PCs where you might want to see the targets (you end up “seeing” what the transponder “hears”). Picture a lot of connections, a lot of possible points of failure, and another way NMEA 2000 can improve marine electronics. In addition, the powers that be are still working on a Class B AIS standard, and while it should bring down unit costs, there’ll be a lag between the finished standard—expected later this summer—and actual equipment.
By contrast, AIS listeners aren’t subject to standards or FCC approvals or complicated installations, and I sense that we’re about to see the field of available products explode. Si-Tex just announced an AIS Radar product that has its own little screen and retails at $700, as well as a $500 black-box “engine” that will plot AIS targets on several Si-Tex plotters or on a PC running a growing number of AIS-capable charting programs. I hear we’ll soon see a combination AIS listener and GPS that uses USB for power and data. And Nobeltec, perhaps the first company to offer AIS listening to yachts, just cut a third off the price of its receiver. So while 90 percent is an exaggeration, it’s surely easier to just listen to AIS.
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This article originally appeared in the August 2005 issue of Power & Motoryacht magazine.