When the unit is receiving a DGPS signal, the SNR (Signal to NoiseRatio) and Distance fields show data. The SNR range is 0 dB to 30dB, with 30 being the best. The Distance may or may not show data,depending upon the signal being broadcast from the DGPS site.The DGPS beacon transmitters are operated by the United StatesCoast Guard (or similar government agency in other countries),which is responsible for their accuracy and maintenance. For DGPStransmitter problems or to find the most updated list of frequenciesand coverage areas, contact your local USCG or see their Web site athttp://www.navcen.uscg.mil/.Advanced NMEA Output SetupIf you are going to interface the GPSMAP 276C with anotherpiece of equipment (such as a radar or autopilot), the unit needsto be set to output NMEA data. The NMEA data transmission canbe customized to keep the output rate at two seconds. If too manyNMEA sentences are activated, the unit may take longer than twoseconds to update.To access the Advanced NMEA Output Setup:1. Press MENU twice to open the Main Menu.2. Use the Rocker key to select Setup from the vertical tab list.3. Select COM 1 or COM 2 from the row of tabs along the top.4. Highlight the field below Serial Data Format. Press ENTER.5. Select NMEA In/NMEA Out. Press ENTER.6. Press MENU to open the options menu. Select AdvancedNMEA Setup and press ENTER.Advanced NMEA Output SetupThe Advanced NMEA Output Setup page allows you to set theoutput rate, change the precision of the Lat/Lon minutes, setWaypoint IDs to names or numbers, and turn on and off the GPSstatus, the GARMIN Proprietary sentences, and Waypoint/Route(WPL, RTE).GPSMAP 276C NMEA Sentence Output (NMEA version 3.01compliant):• Always transmitted: GPRMC, GPGGA, GPGLL, GPBWC,GPVTG, GPXTE, GPRMB• Switchable sentences: GPGSA, GPGSV, GPWPL, GPRTE• GARMIN proprietary: PGRME, PGRMZ, PGRMM90 GPSMAP 276C Owner’s ManualC USTOMIZING YOUR GPSMAP 276C > C HANGING THE DATA FORMAT
