Wesmar HD800/110-10, Installation & Operation Manual

Page: 23 / 100

Page 23
WESMAR
INSTALLATION AND OPERATION
To counter this loss, the TVG curve is adjusted by the
Near Gain and Far Gain control on the front panel.
Near Gain controls the complete gain curve and has its
greatest affect on targets displayed in the fi rst half of the
sonar range. Far Gain controls the height of the gain
curve and has its greatest affect on targets displayed in
the last half of the sonar range.
When both Near and Far Gains are adjusted correctly,
targets at long range will not change in density as the
vessel approaches. Also, target density will remain con-
stant from one range to another. Gain controls can be
adjusted for all conditions the operator will encounter,
ensuring accurate target presentation.
Attenuation Losses are more dramatic in equatorial
waters than in northern and southern waters. Because of
this, wide variations in the TVG slope can be calibrated
for your region. TVG calibration allows the operator to
adjust the end of the TVG slope in range. When cor-
rectly set, all operational adjustments are then made
with the Near and Far Gain controls on the front panel.
The range where the TVG slope ends can be viewed on
the screen marked as a light gray ring. The TVG RING
will move in and out when selecting TVG numbers,
TVG number of 400 equals to 300 meters or 1000 feet.
12.5 THRESHOLD
Function 5-
THRESH BOX highlighted, left of screen.
Press up or down on the SELECT SWITCH to choose
Threshold 1, 2, 3 or 4.
Recommended threshold settings for Sonar A:
a) Schooling fi sh: Midwater, shallow water, schools
close to the surface: Select Threshold 3 or 4 (Select
8 Target Colors in Menu 3.)
b) Dispersed fi sh and fi sh close to the bottom:
Select Threshold 2. (Select 8 Target Colors in
Menu 3.)
c) Bottom fi sh and shrimp: Select Threshold 1.
(Select 16 Target Colors in Menu 3.)
Recommended thresholds settings for Profi le B:
a) Bottom Profi le: For bottom type-soft to hard,