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Such values are good in most conditions. However when navigating in very shallow waters
it may be necessary to switch it to OFF, while in very deep waters with a lot of Surface Clutter
it may be better to increase it to MID or LONG.
In some situations it may be necessary to adjust the STC so the sounder can read through the
surface noise and show the bottom. One indication that the STC needs to be changed is when the
display intermittently changes the depth from the correct depth to a very shallow depth.
The STC can be changed from Short, Mid, Long and Custom.
· STC Length
This is the depth range which the STC operates. In custom mode it can be varied from
0Ft to 1000Ft (60Ft or 255Ft on previous software versions). In preset mode it's value
is reported in the following table.
· STC Strength
It is the starting attenuation value of the STC. It acts by attenuating the Gain of the given
percentage value. In custom mode it can be varied from 0% to 100%. The STC effect
is maximum near the surface, to mitigate the Surface Clutter and it progressively
diminishes to 0 at the selected STC depth.
· Preset values table
When in shallow water and the Fish Finder display is showing a bottom or digital
readout deeper than the actual depth this situation may occur if STC is set to LONG
or MID when the bottom is shallow. This issue may be resolved by adjusting the STC
value to SHORT or even to OFF in very shallow waters.
When in DEEP WATER the Fish Finder display is showing a very shallow bottom or
digital readout this may happen because in conditions of strong Surface Clutter the
Fish Finder may erroneously look on to the Surface Clutter. To solve this situation try
to increase the STC to LONG or to CUSTOM increasing the STC length and strength.
When in DEEP WATER the Fish Finder doesn't see the bottom, this may happen
because the bottom is out of range or is very near to the maximum depth that can be
tracked by the Fish Finder. In the latter case this may happen if the bottom
composition is soft as mud, if the sea conditions are bad, there are thermoclines or
the water is full of suspended materials (silt, plankton). All these factors may affect
considerably the performance of the Fish Finder to be able to see the bottom. In these
CPF180i and CPF300i
NOTE
Figure 17.11.1 - STC - Surface Clutter
Figure 17.11.1 - STC Preset values table
Page 125
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