4 Choosing Range and Start Range values in a bottom-related echogram

A Bottom echogram is mainly used when you want to examine the echoes from fish close to the sea bottom. In a Bottom echogram, the start depth of the echogram is defined by the negative Start Range depth value. The range from this start depth is defined by the Range value.

Context

The Range setting defines how "deep" you wish the EK80 system to detect echoes. In other words, this is the vertical distance between the "top" and the "bottom" of the echogram. The Range setting specifies the "bottom" depth, while the Start Range setting specifies the "top" depth.

The range you specify applies to the currently selected echogram. It is identified with a thick border.Several echogram types are available.

In a Bottom echogram, the Range value is "added" to the Start Range value to determine the vertical depth of the echogram. The Start Range value must be negative because the echogram must start from a preferred height over the bottom.

Example

Start Range and Range in bottom-related echogram

In a bottom echogram, set the Start Range value to –5 metres. This will make the echogram start from 5 metres above the sea bottom. Set Range to the 5 metres plus 10 = 15 metres. The echogram will now show the area from 5 metres above the depth, and down to 10 meters "below" the sea bottom. The sea bottom contour will appear as a flat line.

Procedure

Click in the view you want to activate.

The setting you choose will only be valid for the active view. The active view is identified with a thicker border.

Observe the Main menu.

Its default location is on the right side of the display presentation.

Locate the Start Range function.

Choose a negative value for Start Range to place the start depth at the preferred distance over the sea bottom.

The following methods can be used to adjust this setting:

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Select [+] or [-] to choose the level.

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Select the middle of the button and keep the mouse button pressed. Drag the cursor sideways to increase or decrease the level.

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Select the middle of the button to open the menu. Type the requested value. (You can only do this if you have computer keyboard connected to your computer.)

Locate the Range function.

Choose a positive value for Range to place the bottom of the echogram at the preferred depth under the sea bottom.