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Detection Threshold (DT)
This parameter is used to control the threshold level for detection of signals. Signals
below the threshold level will not be detected, while signals above the threshold will
be detected. Setting the threshold level too low may cause false signals to be detected.
For the FM90 system, two different parameter ranges are used. The default value
for
Detection Threshold (DT)
is
17
.
•
3 to 14
By increasing the parameter value, the threshold level is increased. This range
should normally not be used for FM90 system. During special operations where
extreme range is required, and the interference sources are minor, the parameter
may be set to 8. If interference is present, the parameter can be increased to a
maximum of 14.
•
15 to 20
By increasing the parameter value, the threshold level is decreased. This is the
main range we suggest that you use with the FM90.
Water Profile
Use this setting to set up the FM90 for operation in fresh or salt water. Sound travels
with different speeds in salt and fresh water. For this reason, it is important that the
FM90 knows your water profile. The default setting is
Salt
.
•
Salt
Choose this option if you fish in salty or brackish water. The calculations made by
the sensor will be tuned to match the relevant sound speed.
•
Fresh
Choose this option if you fish in fresh water. The calculations made by the sensor
will be tuned to match the relevant sound speed.
Max shooting speed
The FM90 has a built-in Doppler compensation function which is set up using this
parameter. The parameter and related function is, however, only relevant if sensor data
is desired while the purse seine or trawl is being deployed. It has no effect once the
vessel is stopped and waiting for the net or trawl to sink.
The default value is 1 knot.
Note
If you set this parameter too high, you may create a conflict with the channel selection.
Summary of Contents for FM90
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