About the Automatic Range Mode

The sensor has an automatic range mode that is useful to get better quality echograms when the trawl is close to the bottom.

Principle

Range influences the display of echogram images. The smaller the range, the shorter the listening time and the better the quality of images. But if you set a bigger range, data arrives slower which results in poorer image quality.

You can activate the automatic range mode if you need to get better quality echograms when the trawl is close to the bottom. This mode is recommended when bottom trawling.

The echogram can automatically switch to a 20-meter range when the distance to the bottom is less than 20 meters (1).

The change of range depends on the settings configured on Mosa2.
Note: The sensor requires pitch and roll angles within -25°to 25° for automatic range operation.

Mosa2 settings

The following Sounding Mode options must be set in Mosa2:

  • Automatic Range must be activated.
  • The Mode must be set to Down only.
  • The Down sounding Range (m) must be more than 20 meters.
  • The Refresh Rate must be set to Fast.
  • The Trawl Opening must be lower than 18.5 meters to be able to switch to a 20-meter range.
Note: The trawl opening value sets the minimum distance to see inside the trawl. As a result, if the trawl opening distance is equal or higher than 18.5, the sensor will not reduce the range to 20 meters.

See Configuring the Echo Sounder for details about Mosa2 settings.