Humminbird 900 Series - Manual (Page 34)

Understanding Sonar History
It is important to understand the significance of the 900 Series™ display. The
display does NOT show a literal 3-dimensional representation of what is
under the water. Each vertical band of data received by the control head and
plotted on the display represents something that was detected by a sonar
return at a particular time. As both the boat and the targets (fish) may be
moving, the returns are only showing a particular segment of time when
objects were detected, not exactly where those objects are in relation to
other objects shown on the display.
Real Time Sonar (RTS®) Window
A Real Time Sonar (RTS®) Window appears on the right side of the display in
the Sonar View only. The RTS® Window always updates at the fastest rate
possible for depth conditions and shows only the returns from the bottom,
structure and fish that are within the transducer beam. The RTS® Window plots
the depth and intensity of a sonar return. (See Sonar Menu: RTS® Window).
The Narrow RTS® Window
indicates the sonar intensity
through the use of colors.
Red indicates a strong return
and blue indicates a weak
return. The depth of the
sonar return is indicated by
the vertical placement of the
return on the display depth
scale. The Wide RTS® Window
indicates the sonar intensity
through the use of a bar
graph. The length of the
plotted return provides an
indication of whether the
return is weak or strong. The
depth of the sonar return is
indicated by the vertical
placement of the return on
the display depth scale.
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