Garmin GPSMAP 238 Sounder User Manual

Page 81

Reference

Main Menu: GPS Tab

The Differential SNR (Signal to Noise Ratio) indicates, on a scale to 0-30db with 30db being the

best, the strength of the DGPS signal being received. If no optional DGPS receiver is used with the
GPSMAP 188/188C/238 Sounder, the ‘DGPS Rcvr’ ﬁ eld displays ‘Off. The SNR will depend upon the
mounting of your DGPS receiver and the distance from the DGPS transmitting station.

The GPS Info tab features an options menu that provides access to functions and features relating

to the GPS Info display.

The following options are available by pressing MENU on the GPS Info Tab of the Main Menu:

• Start/Stop Simulator— toggles the unit simulator on or off. Retail Demo mode will restore factory

settings to the unit if left unattended for over 2 minutes. This mode should only be used for display
purposes. User waypoints will NOT be deleted.

• WAAS On/WAAS Off— toggles the WAAS capability of the receiver on or off.

• Track Up/North Up— allows you to select between a north up or track up sky view display for the

GPS Info display only.

• AutoLocate— allows the receiver to locate your position automatically. This process can take up to

ﬁ ve minutes.

• Initialize Position— allows you to initialize the receiver graphically on the Map Page to initially

help the receiver acquire more quickly. See pages 4-5 for instructions on initialization.

• Set 2D Elevation— allows you to manually enter the elevation when in 2D or Simulator mode only.

Any elevation entered will be automatically calculated when the GPS is in 3D mode.

To select a menu option:

1. Using the ARROW KEYPAD, highlight the desired option and press ENTER.

NOTE: If a DGPS receiver is attached to the unit and Garmin DGPS, RTCM In/NMEA
Out, or Other DGPS is enable on Port 2, WAAS will be automatically disabled (WAAS
Off). It is not possible for the GPSMAP 188/188C/238 Sounder to receive WAAS and
DGPS corrections at the same time.

GPS Tab Options Menu

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