GPSMAP 4000 Series Owner’s Manual 51
Using Sonar
USinG
Sonar
Understanding the Split Frequency Screen
Use the Split Frequency screen (dual frequency transducer only) to view both the 50kHz and
200kHz frequencies on the same screen.
From the Home screen, select Sonar > Split Frequency. A 200kHz frequency graph appears on the
left; a 50kHz frequency graph appears on the right.
Depth, temperature,
and water speed
GPS speed and
GPS heading
Transducer
frequencies
Range
Understanding the Temp Log
If you are using a temperature-capable transducer, the Temp Log screen keeps a graphic log of
temperature readings over time.
1. From the Home screen, select Sonar > Temp Log. The current temperature and depth are
shown in the top-left corner.
The temperature appears along the right side and the time elapsed appears along the bottom.
The graph scrolls to the left as information is received.
2. Press MENU to access the following scale settings:
Select Duration to set the time elapsed scale.
Select Scale to set the temperature range scale.
Temperature
and depth
Time
elapsed
Temperature
range
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