Humminbird GR16 - Manual (Page 51)

Display Problems
There are several main conditions or sources of possible interference that may cause problems
with the quality of the information displayed on the control head. Look in the following table
for some symptoms of display problems and possible solutions:
Problem Possible Cause
The control head loses power at
high speeds.
When the boat moves at higher
speeds, the bottom disappears
or suddenly weakens, or the
display contains gaps.
There are no fish detected, even
when you know they are in the
water under the boat, or sonar
readings seem weak or faulty.
If the power output of your boat’s engine is
unregulated, the control head may be protecting itself
using its over-voltage protection feature. Make sure the
input voltage does not exceed 20 Volts.
The transducer position may need to be adjusted. A mix
of air and water flowing around the transducer
(cavitation) may be interfering with the inter-pretation
of sonar data. See your Installation Guide for
suggestions on adjusting the transducer position.
Electrical noise from the boat’s engine may be
interfering with sonar reception. See Finding the Cause
of Noise for more information.
Sonar readings may be affected if the transducer is not
positioned correctly (i.e. mounted at an angle, not
straight down), or there is some kind of mechanical
interference, either because it is mounted inside a hull
that is too thick for proper sonar transmission, the bond
between the transducer and the hull is not airtight, or
because the transducer is dirty. Check with your
Installation Guide for guidance on re-positioning the
transducer, and make sure the transducer is clean.
Low battery voltage may be affecting the power of
signal transmission.
Electrical noise from the boat’s engine may be
interfering with sonar reception. See Finding the Cause
of Noise for more information.
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