Humminbird 957C Understanding Sonar History, Real Time Sonar RTS Window, Bottom Presentation

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).

Bottom Presentation

As the boat moves, the unit charts the changes in depth on the display to create a profile of the Bottom Contour. The type of bottom can be determined from the return charted on the display. A Hard Bottom such as compacted sediment or flat rock appears as a thinner line across the display. A Soft Bottom such as mud or sand appears as a thicker line across the display. Rocky Bottoms have a broken, random appearance.

NOTE: A sloping bottom will be represented as a thicker line across the display. Harder bottoms typically will be displayed with red and softer bottoms typically will be displayed with blue.

The sonar returns from the bottom, structure and fish can be represented as either Structure ID® or WhiteLine®. See Sonar Menu: Bottom View for details on how to set the bottom view.

Structure ID® represents weak returns in blue and strong returns in red.

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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