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Calibration
2 CALIBRATION PROCEDURE
Check the hardware installation
Check that the transducer cable is connected to the correct transducer plug on
the rear side of the EK 500 / EY 500.
Check the internal test oscillator
Select the Transceiver Menu and set Mode to Test.
Select the Operation Menu and set Ping Mode to Normal and Noise Margin to
0 dB.
Select the Test Menu/Transceiver.
The amplitude of the internal test oscillator is now displayed. It should be
-55 dB ±2 dB re 1W on a split-beam sounder and -61 dB ±2 dB re 1W on a
single-beam sounder. If the amplitude is outside these limits, disconnect the
transducer cable and check the amplitude to see if the fault is in the transducer
or in the receiver. The amplitude should now be -49 dB ±2 dB re 1 W on a split
beam sounder, and -55 dB ±2 dB re 1 W on a single beam sounder. If the
amplitude is still outside the limits, the problem is probably related to the
receiver. If it is inside the limits, the transducer impedance should be checked.
Rigging
The following rigging description is to a great extent reproduced from ICES
report 144. The vessel should be anchored in calm and sheltered water. The
depth must be sufficient for separation of sphere and bottom echoes. It is
desirable, moreover, to work in water as deep as possible, consistent with
maintaining a stable platform. Both bow and stern anchoring or tying are
recommended. This is illustrated in figure 1.
Placing of winches
Winches should be used to guide and steer lines to the sphere for its
centering in the echo sounder beam. Affix these winches to the deck railing
in accordance with detailed ship drawings. Place the first winch in the
transverse plane of the vessel running through the transducer. If the
transducer is mounted on one side of the keel, place the first winch on the
opposite side of the vessel. Place the second and third winches on the same
vessel side as the transducer and at equal distances from the transverse
section containing the transducer and first winch.
Each winch must be provided with a long spool of 0.60 mm diameter mono-
filament nylon line, which is marked with small swivels at 5 m intervals,
beginning 10 m from the loose end.
6
P2260/E
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