A long shot this! I've got a really sound Simrad AP11, which works well but I want to improve the heading ref with a modern NMEA 0183 rate compass. It has a j300x interface box, and should be able to accept NMEA heading input however it is an older firmware version (1v6). I understand that I need the 1V8 firmware eeprom to make this work; as my ideas as to where I can find it greatly appreciated.

 

I've tried to find a SIMRAD Rate compass which uses the old 2-wire PWM interface however they appear to be as rare as hen's teeth and I can only find later models, or the Fluxgate-only ones.  I think it might be able to accept a ROBNET (?) network compass, but not been able to track down the right version of that either - so I'm down to an NMEA one and finding the right firmware.

 

I know it is a long shot - the thing works fine, just needs a more stable compass......

 

Thanks