7. Fish Finder
7-14
7.9 How to Balance Echo Strength
A school of fish at a depth deeper than a school of equal strength in shallow water ap-
pears in weaker colors. This condition is caused by the movement attenuation of the
ultrasonic wave. To display the schools of fish in the same colors, use the TVG. The
TVG automatically increases the gain with depth so that echoes of the same strength
and different depths are shown in the same colors. In the illustration shown below, for
example, the TVG is set for 100 m and the TVG level is adjusted. Unnecessary echoes
at a distance less than 100 m are deleted and echoes at depths greater than 100 m
are not adjusted.
1. Press the MENU key to open the menu.
2. Open the [Fish Finder-DFF/FCV] (or [ETR]) menu.
3. Select [TVG HF] (high frequency) or [TVG LF] (low frequency) then push the Ro-
toKey.
4. Rotate the RotoKey to adjust the TVG. Raise the TVG to increase the gain differ-
ence between near and far distances.
5. Press the MENU key to close the menu.
Unwanted echoes
are erased.
Unwanted echoes
Echoes of the same size
are displayed in different
sizes and colors
depending on depth.
Echoes of the same size
are displayed in same
sizes and colors.
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