AIS transponder AND integrated AIS receiver/VHF radio

[Cpt Pat]

Originally Posted by rla

If you'd like to avoid the splitter, workable as they seem to be, realize that the AIS antenna only needs a view of the sky, not altitude as in a VHF.


WRONG


AIS uses VHF channels.
I use a split co ax wire on the back stay or lower shroud, I don't want to be on display for 20 mls annoying others. 5 miles is adequate for others to see you and I have found fishing boats react when you appear on their screen near them. UK south and east coasts and through to the Baltic.

Right. AIS uses 161.975 and 162.025 MHz (and channel 70 for DSC, 156.525 MHz, on occasion).

You make a good point! When I get a conflict alarm on a vessel that's 30 minutes from positional convergence (potential collision), I mute the alarm and manually watch its CPA. If I get distracted, there are no further alerts on that vessel because I muted them, and I risk not being aware the situation is deteriorating. (I have the alarm time threshold set at 30 minutes because, well, I sail single handed and sometimes I need to get a cup of coffee to wake myself up.) I have a Vesper Watchmate, which I love, but as good as it is, it has no capability to configure it so - in the case of muted alarms - a new alarm will be triggered signifying: "the situation pertaining to the vessel for which you muted alarms just got worse."

Early alarms on distant targets could be a problem on a busy vessel. On the other hand, if they get an alarm when my vessel is only 5 minutes out, they are 6 times less likely to be distracted and forget about the conflict. And if I'm in a busy seaway where there are multiple conflicting targets, I'll reach task overload sooner when I'm trying to watch the CPAs on multiple distant targets. In some areas, like the SF Bay, one reaches task saturation that ruins situational awareness.

Added range may not be your friend.

[Dsanduril]

I have watched ships that are 10 or more miles from us turn a few degrees to make sure our CPA did not fall within whatever limits they have. I suspect from observation that for most this is two miles, but I think it varies from master to master. And then when they are clear they turn back to their original heading. For this range is necessary, the closer they get before they are aware of you the more radical the turn required.

I've talked with a few of these vessels, and they all seem to appreciate the leisurely pace at which maneuvering can be accomplished when you have time.

[River Cruiser]

Originally Posted by SVHarmonie

If you properly program your MMSI number into your MFD it will not display an "own ship" AIS icon. That just adds confusion and complexity to your display with no real value.

It is properly programmed with the same mmsi #, SH told me the same thing but the AIS icon still appears on the screen. It is not a problem at all in the 4 years I’ve used it.