I installed my Simrad AI50 AIS 5 years ago, worked flawlessly since. On a recent trip from Florida to Bahamas and then to New England, the Unit would only acquire targets when they were within 4-6 miles, nothing would show on the screen beyond that. We could see large vessels visually and on the radar, that would not appear on the AIS screen until they were within 4-6 nm. We were in Newport for an overnight last week and tons of targets appeared on the Display, all within 5 miles.

I’m suspecting a bad cable / connection with the coax cable from the Unit to the VHF Antenna, or, possibly a bad Antenna. Connection in back of the Simrad Unit is clean and good, my Unit is down below in the NAV out of the weather.

Coincidentally, I installed a small solar panel on top of my Radome this spring, the AIS GPS and VHF Antennas are next to that, but have clear views to the sky. Could it be this has affected the antenna and the ability to acquire targets from some distance like it used to, I think not ?

I will run a new VHF cable and see if that makes a difference. Any Suggestions where to start trouble-shooting this problem ?

Thanks, cheers, John