Echo History Display; How To Balance Echo Strength - Furuno TZTL12F Operator's Manual

7. FISH FINDER (SOUNDER)
7.9

Echo History Display

You can view past echoes which are off the screen. Swipe the screen to the right to
display past echoes. To return to the active display, tap [Cancel Hist] at the top right-
hand corner of the screen.
7.10

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 attenuation of the ultrasonic
wave. To display the schools of fish in the same colors, use the TVG. The TVG auto-
matically increases the gain with depth so that echoes of the same strength and dif-
ferent depths are shown in the same colors. In the illustration shown below, for
example, the TVG is set for 300 ft and the TVG level is adjusted. Unnecessary echoes
at a distance less than 300 ft are deleted and echoes at depths greater than 300 ft are
not adjusted.
Note: This function is not available in the auto mode.
1. Open the home screen, then tap [Settings] - [Sounder].
2. Drag the slider in [TVG HF] (high frequency) or [TVG LF] (low frequency) to set
the level. The TVG setting method changes with the fish finder connected.
Internal sounder (TZTL12F or TZTL15F),
DFF1, DFF1-UHD, BBDS1
DFF3
3. Tap the close button to finish.
7-10
Unwanted echoes
0 ft
300 ft
Echoes of the same size
are displayed in different
sizes and colors
depending on depth.
Fish finder
Unwanted echoes
are erased.
0 ft
300 ft
Echoes of the same size
are displayed in same
sizes and colors.
TVG setting method
The higher the setting the greater
the distance gain.
The higher the setting the lower
the distance gain.