GPSMAP 496 Owner’s Manual MAIn Menu > setuP tAbTo have the unit automatically scan for a frequency:1. With the unit set to GARMIN DGPS or RTCM In/NMEA Out,use the ROCKER to highlight the Beacon field and pressENTER.2. Highlight Scan, and press ENTER. The numbers in theFrequency field change as the unit scans from 284 kHz to325 kHz, 200 bit rate, then 100, at 6-second intervals.Interface tab of the Setup tab with Garmin DGPS selectedHighlight Scanand pressENTERShows thestatus of thescanThe Status field shows one of the following:tuning—the unit is attempting to tune to the specifiedfrequency and bit rate.Scanning—the unit is automatically scanning through thefrequencies and bit rates.receiving—the unit is receiving DGPS signal and ready foroperation.•••Check Wiring—the unit is not making connection withDGPS receiver.To restart the scan:1. Press MENU.2. Highlight Restart Scan, and press ENTER.To manually enter a frequency and bit rate:1. With the unit set to GARMIN DGPS or RTCM In/NMEA Out,use the ROCKER to highlight the Beacon field, and pressENTER.2. Highlight User, and press ENTER.3. Highlight the Frequency or Bit Rate field, press ENTER, andenter a frequency or bit rate. Press ENTER when done.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,based on 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 atwww.navcen.uscg.gov.•
