Bob Baldwin wrote in news:491e43ae$0$5462$bbae4d71
@news.suddenlink.net:

Thanks for the answer - good info! I have searched for NMEA problems and
solutions, but have never found this particular question asked. The GPS
will come from an aux output from the Humminbird 997c fish finder. If
necessary, I can easily disable GPS out from it's menu, leaving the
compass to talk to the radar while checking for storms in the area.
Thanks again - most appreciated!



Leave both the GPS statements and compass statements streaming. Not only
will the chartplotter/radar know WHERE you are, but when you slow it will
show which way the bow is headed (or if you have it set for "course up"
instead of North up, it will point the boat in the right direction no
matter what the speed is.) GPS doesn't know which way the boat's headed,
that's calculated after two GPS fixes by the electronics which THEN points
the boat the way it's going. At rest, GPS has no idea which way you're
pointing....(c;]

Keep an eye on everyone's GPS, especially when they are installing it.
Watch them try to get the antenna in perfect alignment with centerline on
the keel. It's too funny. Which way the stupid antenna is pointing has
nothing to do with the GPS' directions....

....turn it sideways and it reads the same.