Danny wrote:

You need a heading sensor which should have come with the RADAR PC. Your GPS
will only give you heading while under way.

The GPSMAP76S has an electronic compass as well as a GPS.



"none" wrote:
I am using the map76s as a spare gps for my nobeltec charting software on
my laptop BUT it doesn't 'seem' to be using nthe compass data exclusively.
When i turn the gps at a standstill the boat icon turns the same way but
the absolute value is way off...circa 30degrees. Normally when I am
moving the dynamic gps data keeps feeing me heading data but when i am
stopped the radar needs a heading to align the chart to the echos. [the
software is radarPC which is a chart with radar and gps data superimposed]

Is the a way to get the garmin to output that compass heading data or to
check and see if it actually is outputting but the software is not using
it?

The heading based on the GPS PVT solution (eg: velocity) and the heading
from an electronic compass will have different 5 letter sentence names
in the NMEA data. If you can find these two different headers, you can
check your manual to see if the GPSMAP76S outputs both.