44 GPSMAP 400/500 Series Owner’s Manual
Using Sonar
Using Sonar
When connected to a transducer, the following chartplotters can be
used as shnders:
GPSMAP 420s GPSMAP 450s
GPSMAP 421s GPSMAP 451s
GPSMAP 520s GPSMAP 525s
GPSMAP 521s GPSMAP 526s
GPSMAP 550s GPSMAP 555s
GPSMAP 551s GPSMAP 556s

Understanding the Full Screen

Select the Full Screen option to view a full-screen graph of the
transducer’s sonar readings.
From the Home screen, select Sonar > Full Screen.
Transducer
frequency or
beam width
Temperature
Speed
Depth
Range
Suspended
targets
Full Screen

Understanding the Split Frequency Screen

Use the Split Frequency screen (dual-frequency transducer only) to
view both the 50 kHz and 200 kHz frequencies on the same screen.
A 50 kHz frequency graph appears on the left; a 200 kHz frequency
graph appears on the right.
From the Home screen, select Sonar > Split Frequency.