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Signal Interpretation
Hard-bottom readings (rock or gravel) will be displayed by a wide band of RED
light indicating a strong return signal. Conversely, a soft bottom (mud or silt)
will return a weaker signal and will result in a narrower RED band or possibly
even a combined RED and GREEN band. A soft bottom with weed growth will
often appear as a narrow RED or GREEN band combined with both solid and
broken YELLOW segments indicating weeds. Any fish in the weeds may show
as RED or GREEN depending on fish size and relationship within the transmit
beam (in the middle or on the outside of the transmit signal).
Reading Bottom - In interpreting depth, always read the leading edge (shal-
lowest side) of the signal return. If you have a strong signal return (wide band
of RED light) and it starts at 13 feet and ends at 16 feet, the correct depth is
13 feet or the shallowest leading edge of the return signal. Anything beyond
the shallowest leading edge indicates the strength of the return signal.
Reading Fish - Fish will generally appear as separate targets from the bottom.
A fish target can be displayed as RED, YELLOW or GREEN, depending on the
size of the fish and the location within the transmit beam. Larger fish located
in the center of the beam (cone) can appear RED and will be displayed as a
wider band on the display. Smaller fish or fish on the outside of the cone may
appear GREEN or even YELLOW. Fish moving through the transmit beam
may change color as the return signal strengthens or weakens reflecting their
location.
Fish that are right on the bottom can appear as part of the bottom. The best
indication of a fish sitting right on the bottom is that the leading edge of the
bottom return signal is either GREEN or possibly a dithering or flickering RED
segment. It is important that the GAIN or sensitivity be kept to a minimum
when displaying a strong bottom return. Too much GAIN will flood out the
ability to differentiate targets and clutter the display.
Reading Lures or Bait - The LX-3TC will pick up and display small objects
like lures or bait. When tuning the unit to display your lure or bait, lower the
object to the desired depth and turn up the GAIN until you see the lure or bait
on the display. It is important that the GAIN be set so it displays the lure or
bait as you raise or lower it.
NOTE: Too much GAIN will cause clutter and may make it difficult to distin-
guish other targets like fish near the bottom. When tuning the unit to display
lures or bait, make sure that the objects are in the center of the hole and
therefore in the center of the transmit beam. If there’s water current (some
lakes have underwater current or movement) and the lure doesn’t weigh
much, it may move to the outer edge of the signal or out of the transmit beam
altogether. This will make it difficult or impossible to pick it up on the display.
Dead Zone - All sonar units will have a dead zone in certain circumstances.
This occurs on sharp drop-offs where the transmit beam (cone) hits the shal-
lower edge of the drop-off and returns before the deeper edge returns. This in
effect creates an undisplayed area between the shallower and deeper water
within the transmit beam.
