a98, i70, RayControl installation issues

[Doug McEwen]

Chuck: In the above thread, I have an a98 as my primary MFD, and an older backup Navman 5380 chartplotter configured to provide a backup GPS source to the a98 via NMEA 0183. Data source selection currently works perfectly between the internal GPS source and the backup GPS source.

My SPX5 course computer is currently configured to forward heading to the a98 via NMEA 0183, which stops the SPX5 from getting a software update from the a98. In the above thread, you state that it would be better configure the SPX5 to forward heading via STNG to the a98, which would permit software updates to the SPX5. But in the following post: http://forum.raymarine.com/showthread.php?tid=107 you state that an data source selection is not possible in a system which includes an SPX autohelm. I assume this means "in a system in which the SPX autohelm is connected to the MFD via STNG". If I am interpreting this post correctly, it suggests that I have to choose between using STNG which allows for software updates to the SPX5, or using NMEA which allows data source selection for an alternate GPS source.

Am I interpreting this correctly? Thanks in advance for all the helpful advice in this forum.

[Chuck - Raymarine - Moderator]

Doug,

As you have indicated your older generation of autopilot will block Data Source Selection when interfaced to the SeaTalkng backbone. Is your MFD to be used as the primary source of GPS data for the system?

[Doug McEwen]

The Raymarine a98 is the primary source of GPS fix for the system, using the patch antenna built into the a98 housing (not a GA150). I configured a backup GPS source through NMEA 0183 during the design phase because I thought that I might occasionally block the patch antenna's view of the sky while moving around the boat.

As it turns out, since I have been using the a98, it seems that the GPS reception is extremely robust. I have tried to make it fail by deliberately blocking reception, but it always seems to still get enough signal to hold a fix. Given this, I am willing to give up thinking I need a backup GPS source. But I do wonder what would happen with future installations that might put additional duplicate data sources onto the STNG bus. Potentially I am better to keep the SPX5 off the STNG bus to allow the data source selection feature on the a98 to continue to function as it was designed.

[Chuck - Raymarine - Moderator]

Doug,

Should the MFD's internal GPS receiver w/GA150 be the primary source of GPS data for the system, then GPS source selection may be accomplished alternatively by configuring the MFD's Internal GPS to OFF when seeking to use the NMEA 0183 source of GPS data. In this way, the autopilot may continue to be interfaced to the system via SeaTalkng.

[Doug McEwen]

OK, thanks for that alternative approach, and thanks for answering my questions.

[Chuck - Raymarine - Moderator]

You're welcome.