Output NMEA to a VHF

[Didier B]

Hi Didier,

Considering that position input to a VHF is most likely to be useful in an emergency situation, wouldn't you like to have a solution with less complexity involved? A simple standalone GPS with builtin NMEA output would be much more failsafe for this purpose.

Regards

You are 100 % right, all this set of connections looks like a gas refinery (in french : une usine à gaz !). Consequently, I have dramatically simplified the design :
Use of one RS232 NMEA GPS connected to the VHF GPS input;
Redirection in the VHF of position sentences towards the AIS output (a smart option of some recent VHFs) ;
Connection RS232 from the VHF to COM/USB port on the RPi.
RPi will receive both position and AIVDM and send them to Signal K and OCPN;

If the VHF cannot redirect the position to the AIS output then it is possible to connect the GPS TX to both VHF and RPi RXs : in RS2132 one talker can talk to 2 listeners simultaneously !
It is anyway a safe idea to prepare and test this link in case of failure of the VHF, or to save battery on passage making ...

Thanks a lot to have pushed me towards this simplification !