[CA] [CA11] AIS Lost Connection (C90W C12OW C140W)

[Chuck - Raymarine - Moderator]

Stoomy,

Short of configuring the MFD's AIS Dangerous Targets Alarm to OFF, no configuration settings of the MFD can address the reported issue. The feature which you are describing may indeed be resulting from insufficient GPS signal. While not weak enough to trigger a GPS alarm, it may trigger the alarm reported. Additionally, the long retired C-Series Widescreen MFDs were one of the early Raymarine MFD designs supporting limited NMEA 2000 communications. It is possible that the feature reported may simply feature of the design when interfaced via NMEA 2000 communications. As a course of action, it would be recommended that:
- the software level within each of the C-Series Widescreen MFDs be examined to ensure that the software within each MFD has been updated with the latest available Raymarine product software update.
- inspect the installation location be to ensure that the MFD has been afforded an unobstructed view of the skies overhead. It is not uncommon for a bimini top to reduce the strength of the received GPS signal to a level which is lower than that that which the MFD's internal GPS receiver can maintain a quality GPS signal. Under normal conditions, it would be expected that the HDOP for GPS position FIX produced by the MFD's the internal GPS receiver will be 1.0 or less. If higher, then it may be advisable to consider installation of an external GPS receiver.
- given the information provided within the opening paragraph, consider interfacing the third party VHF radio / AIS receiver via NMEA 0183 rather than NMEA 2000 communications. The system should not be simultaneously interfaced to the VHF radio / AIS receiver via both NMEA 0183 and NMEA 2000 communications protocols.
Should you you elect to test the performance of the system when interfaced via NMEA 0183 communications, then the VHF radio / AIS receiver should be disconnected from the NMEA 2000 backbone.