Furuno CH-500 Operator's Manual page 63

4. To reduce reflections from the sea surface or plankton, press
Level] ([TVG Level-LF]/[TVG Level-HF] on CH-600), then press
[TVG Level] settings.
Gain
Hi
Lo
5. Press or to adjust the TVG level. Ideally, a setting between 2.0 and 5.0
should be sufficient. A larger setting reduces the gain over distance.
As the setting is adjusted, the current setting is shown in a dashed line and the
level indication changes to show the new setting.
Gain
Current setting
New setting
6. Press to select [TVG Distance] ([TVG Distance-LF]/[TVG Distance-HF] on CH-
600), then press
Gain
Hi
Lo
7. Press or to adjust the TVG level.
Ideally a setting between 3.0 and 5.0 (130 m to 320 m) is sufficient.
TVG Level
200m
TVG Level
Hi
Lo
200m
to show the [TVG Distance] settings.
TVG Distance
200m
3. VERTICAL SCAN MODE
to select [TVG
4. 0
TVG Level
4. 0
indication
changes to
show the
new setting.
4. 0
to show the
3-5