Interpreting The On-Screen Information - Humminbird 100SX Single Beam Operation Manual

large digital number at the lower left of the display is the depth of the water directly beneath the
transducer location.
The range of the graphic display is shown to the right of the
graphic information. The upper number is 0 indicating the
surface of the water, the lower number is one of the 9 ranges
available which best matches the depth of the water. As the
depth of the water changes, the range
changes as necessary in order to retain a bottom representation
onscreen.
When in Auto mode, the horizontal line at the top of the graphics
area is the 0 line which represents the surface of the water.
Occasionally there will be a gap in this line. This gap indicates
that the unit is updating the display even if the bottom is not
visible on-screen, or if the bottom information is not changing.
The graphic representation of the bottom may vary considerably
depending on the composition and regularity of the bottom surface (see Interpreting the Onscreen
Information). Any sonar return which is determined to be not a part of the bottom is shown
between the surface and the bottom. If this return is determined to be a fish, one of several fish
shapes is drawn which indicate size, depth, and location of the fish (see Interpreting the On-
screen Information).

INTERPRETING THE ON-SCREEN INFORMATION

Figure B shows a typical view you can expect to see on-water.
New sonar information appears on the right side of the graphic
area of the display and moves to the left as new information is
displayed. The 100SX automatically selects the appropriate
depth range to show the depth of water beneath the transducer.
This range is selected so that the bottom representation is
typically shown about 2/3 down the display.
The graphic depiction of the bottom provides the user with an
effective tool for understanding the composition of the bottom. If
the bottom is hard and smooth, the bottom depiction is narrow
and dense. If the bottom is soft mud or sand, the depiction will
be thick and less dense. This indicates that much of the signal
is absorbed by the soft bottom. If the bottom is rocky or rugged
in composition, the depiction is of varying density and textured
in appearance.
Wave action also affects the bottom depiction. Remember that the information drawn is a
distance measurement, so if the boat is moving up and down over flat bottom, the bottom
depiction often appears in regular variations which match wave timing.
Structure is defined as any object physically attached to the bottom. The sonar configuration of
the 100SX is optimized to give the most accurate depiction of bottom structure possible. Grass,
trees, stumps, wrecks or other debris are accurately displayed, however the depiction of these
objects varies with boat speed and direction. The best way to learn to interpret structure is to
operate the 100SX over a variety of known conditions and experiment with user functions to best
represent those conditions on-screen.