I have new
Simrad speed,
transducer, NSS8 mfd and
autopilot with an AC 42
autopilot computer and AP 24 autopilot control
head. I Just installed a replacement AC 42 and calibrated it per the manual. I now notice( and there may have been a difference before that I didn't pay much attention to). That the COG on the autopilot control
head , which is consistent with my standard Richie
compass, is about 10* different than the MFD displayed COG. Am I correct in assuming the MFD gets its COG from its own internal
GPS and that's why? But why such a large variation? I have re calibrated with the same results. Is the internal
gps on the NSS8 that far off?
And there is also a SOG difference of about 1 mph between the MFD and my IS 20 Combi readout. Again is that because the MFD has input from its own GPS. Why doesn't the MFD report what these two sources report since they are all on the
NMEA network? How can I resolve these differences?
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