24
Operation
SeaBat Sonar UI - User Manual
Figure 4-3
Left is a proper range setting and right an incorrect range setting
4.2.2 Power
The power setting allows the operator to increase or decrease the amount
of power (acoustic energy) that is transmitted into the water.
Figure 4-5
Power
If the power is set to OFF, the system will not ping, but it will continue to
receive data provided that the (ping) rate is not set to 0. The sonar system
will act as a passive sonar by only receiving data. This is a feature that is
very useful for monitoring the ambient noise and interference from the
vessel itself.
4.2.3 Gain
The gain setting allows the operator to select the amount of receiver gain
that is applied to the returned sonar signal, in addition to the calculated
gain. The gain is applied throughout the range as a fixed gain value.
Figure 4-6
Gain
The sonar system utilizes a Time-Varied Gain (TVG) by applying a
variable gain to the signal, based upon the formula :
Receiver Gain = 2 α R
km
+ Sp log R
m
+ G
Where:
α
= Absorption loss in dB/km
Sp
= Spreading loss coefficient
R
km
= Range in kilometers
R
m
= Range in meters
G
= Extra gain as set in the Control pane
See Absorption (page 32) and Spreading (page 33) for more information
about this formula.
For some sonar systems the gain can be switched to Fixed mode. Fixed
mode can be used for very short ranges (<10m). The default mode is
TVG.
