Subject: AIS targets picked up by VHF radio vs. by the AIS unit ?
If your VHF radio has the AIS 300 feature and you also have an AIS 300/600/800 also then when the Chart plotter is displaying AIS targets which are being picked up by the VHF radio and/or the AIS unit ?
As a test, one can power off the AIS unit to see what the VHF radio picks up.... and one can have the AIS unit powered on with the VHF radio powered off. If both are powered off when previously being on and AIS targets being displayed, then shortly after the Chart plotter will complain that the targets have been lost.
However, if both are powered up which (radio or AIS) targets are being display ?
The point here is, say your AIS 300/600/800 is malfunctioning yet AIS targets are still being displayed on the Chart Plotter, it's unclear the AIS unit is misbehaving or has quit.... unless you have the 600/800 that also transmits as well as receiving AIS info.
If your VHF radio has the AIS 300 feature and you also have an AIS 300/600/800 also then when the Chart plotter is displaying AIS targets which are being picked up by the VHF radio and/or the AIS unit ?
As a test, one can power off the AIS unit to see what the VHF radio picks up.... and one can have the AIS unit powered on with the VHF radio powered off. If both are powered off when previously being on and AIS targets being displayed, then shortly after the Chart plotter will complain that the targets have been lost.
However, if both are powered up which (radio or AIS) targets are being display ?
The point here is, say your AIS 300/600/800 is malfunctioning yet AIS targets are still being displayed on the Chart Plotter, it's unclear the AIS unit is misbehaving or has quit.... unless you have the 600/800 that also transmits as well as receiving AIS info.