Furuno CSH-53 - Manual (Page 71)

7-17
Reducing Sea Surface Reflections
Sea surface reflections can be reduced by sharpening the hori-
zontal Rx beam width with the NARROW key. You may preset
the reduction level with NARROW in the SONR•BEAM menu
in the data setting window. The normal setting is 0. Increase the
setting when, for example, searching small fish. Note that it is
also useful to increase the setting when observing bottom condi-
tions, since the picture is more detailed.
Boosting Tx Power
When the NARROW key is turned on sea surface reflections are
suppressed, but small fish echoes are also suppressed. In this
case the “boost” feature may be useful.
Press the BOOST key to light the lamp above it. Tx power in-
creases and small fish school echoes are stressed.
When its use is not required turn off the BOOST key.