How To Calibrate The Target Echo Strength - Furuno FCV-2100 Operator's Manual

2. GRAPH FUNCTIONS
2.2.8

How to calibrate the target echo strength

To accurately analyze fish distribution, it is necessary to calibrate target strength using
a calibration sphere with a diameter of at least 38.1 mm. The calibration is done to
match the target strength value displayed in the fish histogram dialog box with the tar-
get strength value of the calibration sphere.
To calibrate the target strength, do the following:
1. Suspend a calibration sphere at least 3 m below the transducer.
2. Set the measurement mode to [Specific Area] (see section 2.2.2).
3. Adjust the area marker (colored rectangle, see section 2.2.6) to place the calibra-
tion sphere echo inside the measurement area. Keep the measurement area
small, to avoid unwanted echoes.
4. Check the fish size displayed on the graph in comparison to the calibration
sphere. Note that calibration can be completed if there are other echoes present.
5. Confirm that the calibration sphere echo appears inside the area marker in con-
secutive scans before proceeding to the next step.
6. Select the [Advance Settings] icon (
7. Select the [Advanced Settings] icon (
Settings] menu is displayed.
8. Select [Calibration]. The [Calibration] options appear on the right of the menu.
9. Select [Calibration Setting], then select the detail icon (
calibration value. The settings pop up window shown below appears.
10. Adjust the value to match the size of the calibrations sphere. Press  to decrease
the value, press  to increase the value.
2-8
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Sound Speed
Measurement
Temperature
Alarm
Bottom Level
External Echo Sounder
Position to Start Bottom Detection
Sounder
HF
Zero Line Rejection
LF
Zero Line Area
Calibration
Zero Line Fill
TX/RX
Draft
System
Gain ADJ
Range
Fish Size
TX/RX
Calibration Setting
Control Unit
User Interface Settings
Calibration
Stabilization
Mode Mode M d
Test Test Test Tests T Test t s s s s
S S i
Calibration
sphere
size
Measured
size
) from the InstantAccess bar™.
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) to the right-side of the