Originally Posted by chrisr
could it be that your friend had only just turned her AIS on and your system was taking a few minutes to register the data ? did the target appear later ?
This would be my first guess. Where was the "list" that it showed up on?
My Vesper AIS transceiver will remember targets for a while, but obviously the chartplotter
or radar can only display those that have been received since they were powered on.
AIS transmits less frequently when at anchor
than when underway. With Class B it could be several minutes. Something makes me want to say six minutes, but I might stand corrected on that.
Whatever the number, if the AIS receiver was on when the friend's boat last transmitted, but the chartplotter
or radar hadn't fully booted up yet, it would be very possible that you'd see it on the AIS but not the other devices for several minutes. Also, the static information (boat name, size etc.) is transmitted even less frequently. The other devices might wait for that before displaying the target.