Active menu
The Active menu offers parameters related to current views and data presentations provided by the SU90 system.
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How to open
Select the Active icon.
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The icon is located under the Main menu. Select the icon one more time to close the menu.
Description
Only brief descriptions are provided. For detailed information about each function and dialog box, refer to the Reference manual or the context sensitive on-line help.
Tip
If you do not need to use the menu system, you can hide it. This allows more space for the echo presentation.
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Use Menu on the top bar to hide or show the menu. When the menu system is hidden, it appears temporarily on the left or right hand side of the screen if you move the cursor to that position.
The choices in the this menu depends on which view in the display presentation that is currently "active". The menu may therefore change from one view to another. The name of the currently active view is identified at the top of the menu. The screen capture may not show you all the menu choices.
Note
Before you can change the settings related to a view, you must click inside the view to activate it. The changes you make are by default only valid for the active view. Several of the functions offer Apply to All. If you select Apply to All your setting is applied to all the views in the current presentation mode.
•  TVG (Time Variable Gain)
When an acoustic pulse is sent through the water, it will gradually lose its energy. The greater the distance between the transducer and the target(s), the greater the loss of energy. TVG (Time Variable Gain) compensates for the loss of acoustic energy due to geometric spread and absorption.
•  Ping-Ping Filter
The Ping-Ping Filter analyses the historical information from previous consecutive pings in order to remove unwanted noise and interference from the echo presentation.
•  Pulse Type
The Pulse Type function allows you to select the "shape" of the transmitted pulses ("pings"). Different shapes have different qualities. Which pulse type to use depends on the current environmental conditions, your range to the target(s) and the type and speed of the target(s) you are observing.
•  Bandwidth
The Bandwidth function allows you to select the frequency range in the SU90 system transmissions ("pings").
•  Frequency
The Frequency function allows you set the centre frequency for the Hyperbolic Frequency Modulated (HFM) and Linear Frequency Modulated (LFM) transmissions (pings), and the operating frequency for the Continuous Wave (CW) pings.
•  Horizontal TX Sector
In a horizontal swath the SU90 system transmits maximum horizontal opening angle xxx. By means of the Horizontal Tx Sector function, you can change this opening angle to 360°. The function is only available in the Horizontal, Plane and Inspection views.
•  Vertical TX Sector
In a horizontal swath the SU90 system transmits with maximum vertical opening angle xxx. By means of the Vertical Tx Sector function, you can change this opening angle to 4.9 to 7°. The function is only available in the Vertical and Navigation views.
•  Range Projection
The distance to a target located anywhere in the water column can be measured in two ways. This can either be the horizontal distance to the target (True), or along the tilt angle (Slant). The Range Projection function defines how this distance is measured.
•  AGC (Automatic Gain Control)
The AGC (Automatic Gain Control) function runs an automatic analysis of the echo strength.
•  RCG (Reverberation Controlled Gain)
The RCG (Reverberation Controlled Gain) function removes unwanted reverberation from the bottom and or from the sea surface. This enhances the visibility of schools. It may however also remove scattered fish from the presentation.
•  Bottom Filter Threshold
The SU90 system provides a bottom filter to reduce the sometimes powerful echo from the seabed. This filter is useful if you try to find fish close to the bottom. Select a Bottom Filter Threshold value to control the "strength" of the filter. A higher numerical increases the filter efficiency and reduces the bottom echo accordingly.
•  Noise Filter
The Noise Filter removes unwanted acoustic noise from the display presentation. It reduces the interference from other acoustic systems (sonars and echo sounders), as well as the noise from the propellers.
•  Horizontal Scroll
The Horizontal Scroll function controls how fast the echo presentation shall move from right towards left in the Echogram and Inspection views. The speed is controlled by adjusting the number of pixels used to present each ping. A higher speed will update the view faster, but will also reduce the resolution.
•  Vertical Reference
The function is only available in the Vertical view, as well as the vertical Navigation view.