[CA] E120 data feed, move from Seatalk 1 to Seatalk ng

[lotharjt]

Chuck, attached is the relevant pieces of the current installation. Some comments:

- ship was equipped with current RS125 outputting NMEA 0183 direct to the Ray215 radio (to keep it happy with GPS position), then the signal was routed to the S3G pilot which I believe has been bridging the GPS data (lat/long, COG, SOG) to Seatalk 1 and that's how the Master E120 has been getting all its data including GPS.

Note too that the S3G is sourcing power for the Seatalk 1 bus and now via the bridge, it is acting as the primary power for the NG bus. I intend to run a dedicated power feed to the approximate center of the bus but have not done so yet. Possibly an issue?

So step 1, I laid in the simple NG backbone with the Seatalk 1 to NG converter / bridge and an ITC-5 with windvane. I ran this without the AIS connected nor the i70s and GPS lat / long has not been displayed on the E120 but SOG and COG have. I did note that sometimes the SOG and COG would blank momentarily on the plotter but generally solid.

Step 2, I disconnected the NMEA 0183 feed to the S3G and confirmed that all GPS data including COG and SOG goes to 'dashes', what I would have expected. Then connected the external AIS which is configured to output all GPS data via its NMEA2000 port. Result was COG and SOG now displayed solid on the E120 but lat / long still not present. Seems like it could be a configuration issue or parity or something silly like that.