AIS glitch?

[SV__Grace]

Got a Garmin AIS unit hooked up to NMEA 2000, B&G Zeus MFD using Navionics software.

Used to be able to see AIS signatures miles away and now can only see those within a few miles.

Reset the system, same result. Antenna looks fine. Sending and receiving seems to work fine.

System settings for hiding AIS signatures by distance is disabled as it always has been, but it's as if the system is hiding signatures more than 2 miles or so.

Ideas?

[smac999]

Plug the ais into your computer via usb abd Garmin software. . If will give you atenna swr Info. And list of all boats and their distance.

Probably bad antenna or connection.

[donradcliffe]

Most likely electrical noise on your boat.

[Pandor]

Originally Posted by SV__Grace

Got a Garmin AIS unit hooked up to NMEA 2000, B&G Zeus MFD using Navionics software.

Used to be able to see AIS signatures miles away and now can only see those within a few miles.

Reset the system, same result. Antenna looks fine. Sending and receiving seems to work fine.

System settings for hiding AIS signatures by distance is disabled as it always has been, but it's as if the system is hiding signatures more than 2 miles or so.

Ideas?

Older AIS units and some plotters were restricted in the number of AIS targets that can track. Actually, newer ones are, too. But the newer units tend to track a larger number (up to a hundred or so). I think the older Garmins could only track 30. Therefore, if you were in an area with lots of nearby targets, you would not be able to see those at greater distances.

[tanglewood]

A lot of displays can filter targets that are more than a certain distance away, or moving less that a certain speed. I would check you MFD to see if you have such filtering enabled. It’s in the MFD, not the AIS