Chapter 6: Fishfinder application 81
TVG (Time Varied Gain)
The TVG (Time Varied Gain) reduces clutter by varying the gain
throughout the water column. This function is useful for reducing the
appearance of ‘noise’.
Increasing the TVG value increases the maximum depth to which
TVG is applied; decreasing it reduces the maximum depth. A low
TVG value has little effect on gain in shallow water; a high value
decreases the gain in shallow water so that only the strongest ech-
oes are displayed.
Power setting
The power setting controls the power level of the transducer.
To adjust power settings:
1. Press the PRESENTATION softkey.
2. Select from the appropriate POWER options on the toolbar.
3. In manual mode, use the trackpad to choose the power setting
you want to use.
4. Press OK.
Power settings:
• Auto
This is the default setting. When it is selected the DSM automat-
ically determines the required power setting based on the
current depth, speed, and (bottom) signal strength.
• Manual
If you wish to manually adjust the power to suit current condi-
tions, you can adjust the power level between 0% and 100%, in
10% increments. Lower
power levels are normally used in depth
ranges less than 8 ft. (2.4 m) and higher
power levels are typi-
cally selected for depths greater than 12 ft. (3.7 m).
Dual / Single frequency view
Dual frequency operation allows the sonar to operate and display 2
frequencies simultaneously.
If the preset you are using has two frequencies, you can view either
one or both of those frequencies in separate windows.
To set frequency views
1. Press the PRESENTATION softkey.
2. Toggle to F1, F2 or BOTH on the VIEW softkey.
3. Press OK.
To configure your transducer for dual frequency
1. With a fishfinder window active, press and hold the PAGE/MENU
button.
2. Select Configure Frequency Presets.
3. Use the trackpad to assign the required preset frequencies
Note: The DUAL preset has dual frequency values as a default
setting.
See Configure Preset Frequency settings on page 85 for more infor-
mation on assigning frequencies.
