Sensitivity - Hondex HDX-121 Operation Manual

SENSITIVITY

Whole Display Gain Adjustment
Digital echo sounder is capable of changing the whole past image.
This function helps to find the optimized gain set-up for whole image (past
recording data) with easy manual operation.
Single Frequency Display
Operation for single frequency display.
Both keys, [GAIN1] and [GAIN2], changes the sensitivity.
Select single or dual frequency display from menu.
Dual frequency is selected for default set-up.
Gain
Adjust the gain to distinguish the sea bottom
and fish school. (0~40: 40 steps of sensitivity
level) Optimum sensitivity is to have 2
reflection of sea bottom and red color bottom.
nd
2 Reflection
st
1 reflection is first reflected sound from sea
nd
bottom. 2
from the sea surface and reflected again from
the sea bottom. Usually, 2
twice deeper than sea bottom (1
1
Lower Sensitivity
Press
the sensitivity and gain bar.
GAIN1 key
Higher Sensitivity
GAIN2 key
Press
increase the sensitivity and gain bar.
81
( page87)
reflection is the sound reflected
nd
reflection is located
key of GAIN1 or GAIN2 to lower
key of GAIN1 or GAIN2 to
nd
st
reflection).