Note that scattered fish may be more difficult to spot if the RCG
function is active, as these can be misinterpreted as reverberation.
It is therefore important that you use the RCG with great care if
your are searching for scattered fish.
Default setting on the SP90 sonar is
Medium
.
Sector
The SP90 sonar can transmit the sound in two shapes;
Omni
or
Sector
.
An Omni transmission means that the sound is transmitted in a
full 360 degrees circle around the vessel, while Sector means that
it is transmitted in a defined direction shaped like a cone. The
Sector transmission will provide you with a longer range.
Tilt
The sonar beam can be tilted vertically in steps of 1 degree, and
the chosen tilt is shown on the sonar picture. At 0 degrees tilt
you will transmit the sonar beam in parallel with the sea surface,
while 90 degrees tilt will direct it straight down.
(CD015005D)
C
B
A
The challenge will always be to find a tilt that prevents the fish
echoes to be buried in reverberation and bottom echoes.
If you use a steep tilt (A) the fish will easily be disguised by
the bottom echoes, but a strong RCG setting will help. As the
distance from the bottom to the fish increases, the fish will
be easier to see when the RCG removes the bottom echoes.
However, this assumes that the fish echoes are considerably
stronger than the bottom echoes.
850-165261/A
35
Summary of Contents for Simrad SP90 Series
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