5 Processing the echo data
The fifth page in the Calibration Wizard allows you to manually "clean" the echo data before you process it to calibrate the EK80. When the processing is finished, you can save the results, and update the calibration data used by the EK80.
Prerequisites
In order to process echo data for calibration, you must have imported and saved valid echo data from a relevant calibration target (sphere) inside the beam.
Context
The fourth page of the Calibration Wizard dialog box is divided into three fields.
Tip
To change the size of the individual field, click and drag the field borders. You can also increase the size of the dialog box. To make the dialog box cover the entire screen, double-click the title bar.
•  Target Position field
The left side of the Target Position field shows all the individual echoes that are imported into the calibration program. All echoes are placed inside a circle to reflect their locations in the beam. The right side of the field shows the calibration layer that is automatically created once the calibration starts.
•  Frequency/Target Strength field
The Frequency/Target Strength field shows a curve reflecting the target strength of the sphere for individual frequencies. This is the same curve as you can see in the Calibration Wizard dialog box page four, but with a few additional features.
•  Numerical field
The Numerical field provides several tabbed pages.
–  The General page shows the common data and parameters for the system. Transceiver parameters common to all beams
–  The Channel Data page displays numerical parameters related to the transceiver channel that was used to record the echo data.
–  The TS Data page displays the numerical parameters related to each individual echo.
–  The Results page displays the numerical parameters that are created by the calibration processing.
–  The Error Analysis page displays all the individual echoes that are imported into the calibration program.
Procedure
1 Open the TS Data page in the Numerical field to access the individual echoes.
2 Remove the echoes you do not wish to use in the calibration.
a Click at the top of each column so sort the table.
b In the Suspended column, select individual echoes to remove them from the processing.
3 Open the Error Analysis page in the Numerical field to identify errors.
4 Identify echoes that are too strong or too weak.
a Investigate the echoes by adjusting the colour scale.
b Open the TS Data page in the Numerical field to access the individual echoes.
c Remove the echoes you do not wish to use in the calibration.
If the calibration results are suspect or unacceptable, an appropriate dialog box will appear with this information.
5 Select Reprocess to run the calibration processing.
6 Finalize the calibration process.
a Select Finish.
b Select Save or Save As to save the calibration data.
c Update the calibration used by the echo sounder using Merge or Replace.
These options are not valid for CW calibration. In CW, several sets of calibration values are saved, one for each pulse duration.
When you calibrate with FM pulses, use Merge or Replace as follows:
•  Use Merge if you are calibrating with more than one sphere. This will cover the entire frequency range of the transducer. Used together, these spheres will provide you with a wider frequency band, and the calibration results are merged.
•  Use Replace to remove all old calibration results. This allows you to only use the latest parameters for the relevant channel.
In FM, one single set of calibration values is saved, and this set covers all pulse durations.
d Close the Calibration Wizard dialog box, and resume normal operation.