External GPS Antenna Connection
This device requires GPS position data to transmit position reports, and is equipped with an internal GPS antenna.
If the mounting location does not have good GPS reception, you can install an external GPS antenna (not included), and connect it to the GPS port. You can purchase a GPS antenna from your Garmin® dealer or you can go to garmin.com/SignalVHF-Accessories.
If you do not install an external GPS antenna, you must make sure the radio is installed in a location free of potential sources of interference, such as metallic objects or surfaces covering the device.
NOTE:
The radio cannot transmit position reports based on position data from a networked
source, such as a device connected to the NMEA 2000® network. The radio shares its own position data to other devices on your NMEA 2000 network (NMEA 2000 PGN Information).