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What’s on the Down Imaging™ Display
Understanding the
Down Imaging™ Display
The images you see on the Down
Imaging™ display are produced
using sonar technology. Each time
the unit pings, a strip of data
representing
all
the
echoes
received by the transducer are put
together on the display to form the image that you see. Like traditional 2D
Sonar, the sonar history scrolls left across the screen.
Interpreting the Display
Down Imaging™ beams “illuminate” the bottom contour, structure, and fish.
The beams are wide (side to side) but very thin front to back.
Use the light and dark parts of the display to interpret the objects under your
boat as follows:
•
Dark shades
represent soft returns (mud, sand) or descending
terrain.
•
Light shades
represent denser terrain (timber, rocks) or rising terrain.
A very hard bottom may appear as
white
on the display.
•
White Streaks
or
Clouds
may represent fish on the display.
•
Shadows
are not caused by light but by the lack of a sonar return.
Objects standing on the bottom cause a sonar shadow to appear on
the display. The longer the shadow, the taller the object. Fish may
also cast shadows. You can use the shadow to interpret where the
fish or object is located in relation to the bottom.
Down Imaging™ Sensitivity
Use
Down Sensitivity
to control how the sonar returns appear on the
display. Increase the sensitivity to reveal weaker returns that may be of
interest, especially in very clear water or greater depths. Decrease the
sensitivity to eliminate the clutter from the display that is sometimes present
in murky or muddy water. See the
Down Imaging™ X-Press™ Menu
for
more information.
Freeze Frame and Active Cursor
Freeze Frame and Active Cursor -
Press any arrow on the 4-WAY Cursor
Control key, and the screen will freeze and a cursor will be displayed. Use the
4-WAY Cursor Control key to move the cursor over a sonar return, and the
depth of the sonar return will be displayed in the cursor dialog box.
Zoom:
Use the zoom keys on your control head to see the returns near the
cursor location at a higher magnification. See
Views: Down Imaging™ View
for more information.
Summary of Contents for 858 HD DI
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