Garmin GPSMAP 168 Sounder Owner's Manual And Reference Manual page 83

Reference
Main Menu:
Comm Tab
You may also manually enter a bit
rate and frequency.
The 'SNR' and 'Distance' fi elds will
show data when a signal is received.
74
To manually enter a frequency and bit rate:
1. With the unit set to 'Garmin DGPS' or 'RTCM In/NMEA Out', use the ARROW KEYPAD to highlight
the 'Beacon' fi eld and press ENTER/MARK.
2. Highlight 'User' and press ENTER/MARK.
3. Highlight the 'Frequency' or 'Bit Rate' fi eld, press ENTER/MARK, then enter a frequency or bit rate
and press ENTER/MARK when done.
The 'Status' fi eld will show one of the following:
• Tuning— unit is attempting to tune to the specifi ed frequency and bit rate.
• Scanning— unit is automatically scanning through the frequencies and bit rates.
• Receiving— unit is receiving DGPS signal and ready for operation.
• Check Wiring— unit is not making connection with DGPS receiver.
When the unit is receiving a DGPS signal, the 'SNR' (Signal to Noise Ratio) and 'Distance' fi elds will
show data. The SNR range is 0dB 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 U.S. Coast Guard (or similar government agency
Status
in other countries), which is responsible for their accuracy and maintenance. For DGPS transmitter
Field
problems or to fi nd the most updated list of frequencies and coverage areas, contact your local USCG,
or see their web site at http://www.navcen.uscg.mil/.