Garmin GPSMAP 420 Owner's Manual page 39

Transducer at Surface
Enter a (+) positive number
to show depth from the
bottom of the keel.
Transducer at Bottom
of Keel
Enter a (-) negative
number to show depth
from the surface.
Keel Offset
Transducer—select the transducer type (Dual Frequency or Dual
beam), set the temperature source, sonar cone angles, and calibrate
water speed.
• Temp Source—set the temperature source
• Sonar Cone Angles—when using a transducer other than the
standard Garmin transducer, you can set the angle, in degrees,
of the sonar cone so it is accurately depicted on the Fish Eye
3D screen.
NOTE: The Sonar Cone Angles setting does not affect a
standard Garmin transducer, and should only be used to match
the specifications of a non-standard transducer.
GPSMAP 400 Series Owner's Manual
®
(Transducer or NMEA).
• Calibrate Water Speed—to use a speed sensing transducer,
use this menu to calibrate the speed sensor. If you do not have
a speed sensing transducer, this menu does not appear.
To calibrate the speed sensor:
1. From the Home screen, select Configure > My
Transducer > Calibrate Water
2. Bring the boat to cruising speed. Note your top speed, and
then stop the boat.
3. Highlight OK, and press SELECT.
4. Use the ROCKER to enter your top speed, and press
SELECT.
NOTE: If the boat is not moving fast enough or the speed sensor
is not registering a speed, a "Speed Too Low" message appears.
Highlight OK, press SELECT, and safely increase boat speed. If
you get the message again, stop the boat and make sure the speed
sensor wheel is not stuck. If the wheel turns freely, check the
cable connections. If you continue to get the message, contact
Garmin Product Support.
c u
onfIGurInG the nIt
Boat >
Speed.
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