Furuno FCV-30 Operator's Manual page 73

3. CHANGING SETTINGS
Echo image dialog box description
Auto range/shift: Set up for automatic bottom tracking. "Bottom search" must be on to use
auto range or auto shift. OFF turns off automatic range and automatic shift. Auto range
automatically changes the range with depth change. Auto shift automatically places the
bottom echo at the bottom of the screen without changing the basic range.
Range: If the factory-prepared display ranges or zoom ranges are not to your liking, you
may use your own ranges, by doing as follows:
1. Click the User Setting button below the Range box or Zoom range box.
User range dialog boxes
2. Click ◄ or ► successively in the appropriate Range box to set range.
Note: To restore factory-prepared ranges, click the Default button. To sort ranges in
order of low to high, click the Sort button.
3. Click the OK button.
TX rate: 20 TX rates are available. Normally, the highest rate (20) is used. When in shallow
waters second reflection echoes may appear between surface and actual bottom echo. In
this case, lower the rate.
STC: STC is useful for suppressing surface noise (plankton or bubble, etc.) The setting
range is 0-10; the higher the setting the greater the extent of suppression. Setting 10
suppresses noise up to 5 m. Turn off the STC when there is no noise on the screen,
otherwise weak echoes may be missed.
TVG curve: Choose the TVG curve to use. The higher the numeric the higher the gain with
depth.
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