Raymarine forum

When I power up my Raymarine system on my sailboat (eS97, AIS650, Ray70 VHF, AIS/VHF Splitter, autopilot, wind and depth instruments) my chart shows AIS targets at further than 25nm. All seems well.

After a couple minutes the targets outside of 5-6nm disappear. This does not happen on occasion--it happens ever time I fire up the system. If I reboot, the targets reappear for a couple minutes then disappear once again. I checked the targets against MarineTraffic and they were legit targets.

My antenna is on the top of the 65' mast. The VHF replies to a radio check beyond 25nm.

I am stumped. I have check all the VHF connections. No AIS faults show up.

Is there an AIS setting hidden somewhere that limits the number of targets or the range? The largest number of targets that I have encountered appears to be around 40-50.

Any insights would be greatly appreciated.

Hi djpowers
Thank you for your enquiry.

Check that the AIS receiver in the RAY70 is turned OFF, if you have both the AIS650 and the RAY70 enabled, then it is possible the data is conflicting and triggering the issue.

Can you also check the vessel's location versus the location of the distant targets - it is possible that the furthest targets may be transmitting via a repeater station and this can trigger issues.

Check the VSWR of the AIS650 via the PROAIS2 software - supplied with the AIS650, this will indicate any issues with the antenna cabling between the AIS650, the Splitter and the VHF aerial. click here for more information regarding aerial checks.

It is possible a defective AIS splitter or connection in the cable could be reducing the efficiency of the AIS triggering this issue.

There is no setting in the software which reduces the visible targets

Regards

The solution was simple, there is a maximum of 100 targets to be displayed. As more targets were transmitting AIS data, the furthest were dropping off. When I was in the open sea, I was receiving targets from nearly 30 miles and held them until they were out of range. I can understand why you do not need to display more than 100 targets and the furthest are the least valuable.

Thank you for your help!

Hi djpowers

you're welcome