How does the MFD12 get data that allows it to show the DOP of a N2K gps antenna? Looking at the N2K pgn's that can be received by the MFD12, it looks like 129539 (GNSS DOPs) is not supported by the MFD12?
The MFD12 supports GNSS Position data (129029); 129540 (GNSS Sats in view); 129538 (GNSS control status); along with some propitiatory communications from any Furuno GPS or Sat compass. I haven't heard of any reports HDop not working. You are correct it doesn't specifically read the 129539 PGN.