Honda HE-1500 Operation Manual page 18

※When the unit is delivered from factory, dual frequency display mode is set.
[Gain]
This adjusts the sensitivity to distinguish the bottom or fish school easily.
32 steps of sensitivity from 0 to 31 is displayed in bar.
Optimum sensitivity is that second reflection from bottom is barely displayed.
[Second reflection]
First received echo reflected from bottom is called the first reflection. It's
first reflection reflected from the surface of water goes toward the bottom
again. The next reflection from bottom is called the second reflection.
Normally, it's second reflection is shown on the twice depth of the actual
bottom (first reflection).
Gain Bar
GAIN1 ▲ key
GAIN1 ▼ key
Bottom is shown in green or
white.
1 [To decrease sensitivity]
Each time when you press GAIN1 ▼ key,
gain bar becomes short and the sensitivity
BBottom
decreases.
2 [To increase sensitivity]
Each time when you press GAIN1 ▲ key,
2nd
gain bar becomes long and the sensitivity
Reflection
increases.
As second reflection is shown,
it is easy to distinct the fish
school.
14
GAIN1 ▲ key
GAIN1 ▼ key
As plankton, stains in water,
and etc. are shown, it is difficult
to distinct the fish school.