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3. The water may be deeper than the sonar’s ability to find the bottom. If
the sonar can’t find the bottom signal while it’s in the automatic mode, the
digital will flash continuously. It may change the range to limits far greater
than the water you are in. If this happens, place the unit in the manual
mode, then change the range to a realistic one, (for example, 0-100 feet)
and increase the sensitivity. As you move into shallower water, a bottom
signal should appear.
4. Check the battery voltage. If the voltage drops, the unit’s transmitter
power also drops, reducing its ability to find the bottom or targets.
Bottom echo disappears at high speeds or erratic digital reading or
weak bottom echo while boat is moving
1. The transducer may be in turbulent water. It must be mounted in a
smooth flow of water in order for the sonar to work at all boat speeds. Air
bubbles in the water disrupt the sonar signals, interfering with its ability to
find the bottom or other targets. The technical term for this is ‘Cavitation’.
2. Electrical noise from the boat’s motor can interfere with the sonar. This
causes the sonar to automatically increase its Discrimination or noise
rejection feature. This can cause the unit to eliminate weaker signals such
as fish or even structure from the display. Try using resistor spark plugs
or routing the sonar unit’s power and transducer cables away from other
electrical wiring on the boat.
No fish arches when the Fish ID feature is off:
1. Make certain transducer is pointing straight down. This is the most
common problem if a partial arch is displayed. See the Fish Arch section
in your owner's manual for more information.
2. The sensitivity may not be high enough. In order for the unit to display
a fish arch, it has to be able to receive the fish’s echo from the time it enters
the cone until it leaves. If the sensitivity is not high enough, the unit displays
the fish only when it is in the center of the cone.
3. Use the Zoom feature. It is much easier to display fish arches when
zoomed in on a small range of water than a large one. For example, you
will have much better luck seeing fish arches with a 30 to 60 foot range than
a 0 to 60 foot range. This enlarges the targets, allowing the display to show
much more detail.
4. The boat must be moving at a slow trolling speed to see fish arches. If
the boat is motionless, fish stay in the cone, showing on the display as
straight horizontal lines.
