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(Matti Raustia) wrote in
:

Wondering if my old Sailor RT2048 should be replaced by VHF with DSC
capabilities. AIS output as NMEA sentences from the VHF would be quite
nice option so I wouldn't need to install new antenna, buy AIS
receiver etc to get AIS info in excellent SeaClear charting program.
Is there one available?

matti

AIS is a TIME SYNCHRONIZED slot data mode, similar to TDMA cellular phone
technology, not a bunch of serial data sent at random like NMEA uses. It
requires the attention of the AIS receivers and synchronizing modems at all
times with no time for scanning other channels, as you infer. The NMEA
sentences any AIS receiver generate are not what is transmitted on the air,
no relation at all. The receiver decodes the AIS data stream, time
synchronized from all users, and a separate circuit generates the NMEA
serial data stream with its headers for NMEA devices to use.

It's not going to come out of your VHF radio. Put that out of your mind.
I suspect and hope all boats over 30' carry transponders in the near
future, with NMEA chart plotter output if we have to stick to such archaic
technology.