Kongsberg Simrad ST90, Reference Manual

Page: 96 / 690

94
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Controlling the gain and range settings
Topics
Adjusting the gain (echo sensitivity), page 94
Adjusting the TVG (Time Variable Gain) setting, page 96
Adjusting the sonar range, page 97
Expanding the range within the sonar view, page 98
Adjusting the intensity of the echo presentations, page 99
Changing the tilt, page 100
Adjusting the bearing, page 102
Adjusting the gain (echo sensitivity)
Some echoes are weak while others are stronger. To compensate for this it is often necessary
to adjust the sensitivity of the ST90 system. This adjustment is commonly referred to as
gain .
Context
You can compare this gain setting with the volume control on your car radio. When the gain
is increased, the echoes will appear stronger. Weak echoes will be easier to see. However,
since you also increase the acoustic noise in the reception, the echo presentations will also
show this noise. Too much gain may therefore "distort" the presentation.
Comparing the gain function with the volume control on your car radio is not very accurate.
In fact, the gain in the ST90 system is constant. The
Gain
function is used to adjust the
sensitivity. This is done by controlling the minimum level of detection. When you increase
the gain level (more positive number), you reduce the minimum level of detection, and
thus
increase the echo sensitivity.
Simrad ST90 Reference Manual