Magnet VX2 magnetic declination

[jcrellin]

I have Navnet VX2 plotter/ radar, GP32 (outdated) for GPS and Navpilot autopilot, all set on magnetic heading. The GP42 and the autopilot show the correct COG but the plotter shows the COG as true ( ie 21 degrees out)
I can correct it by going into setup and setting the declination to manual and entering the 21 deg declination. The auto declination option seems to set declination at 0 deg
Not sure when this happened maybe summer of 2022
Any ideas

 

[Johnny Electron]

The automatic MAG VAR applicate requires the use of time and date that is now wrong on your GP32. You would either replace the GPS for a newer one that hasn't rolled over or manually apply the MAG VAR if you must use the TRUE setting.

 

[jcrellin]

Thanks Johnny, the GP 32 also has us in the trees in tight anchorages so I guess it is time to retire it. Do I need a special GPS to talk to the VX2?

 

[Johnny Electron]

The Vx2 can use any standard NMEA 0183 RS422 level GPS source.

 

[jcrellin]

I will get a new gps but not until the fall, we are no where near a place to get one.
As a temporary fix, if I were to hook up the 38400 AIS data port on my AIS transceiver to the VX2, would it pick up the GPS signal from that source as well or would I need to connect the 4800 baud port on the AIS to the Navnet as well. I am assuming that if I have a NMEA 0183 port on the AIS it is likely RS422, it doesn't say so?

 

[Johnny Electron]

No, if using (data 2 only on 10.4 or data 1 of 7") AIS, only AIS will be processed by the port. AIS is something that came about after the Vx2 and used to require an expensive interface until software changed it to allow direct connection. GPS will need to come into a different port. AIS will only process on the one port that the Vx2 is looking to process it from.