Page 49 - HydrophoneHandbook_eReader_Ed2_20151208
P. 49

Best Practices

8. Store the hydrophone in its supplied case, which is designed
    to ensure the sensing element is safe from handling. Keep
    the hydrophone in a stable and controlled environment.

9. When sending the device(s) for recalibrations, use the
    originally supplied case. Package the original case in a foam
    filled cardboard box for shipping.

9.2 Environment:
1. Use clean de-ionized and degassed water for high intensity

    measurements. Degassed water reduced the risk of
    cavitation damage by removing gases in the water. Using
    degassed water also improves the accuracy of the readings
    by reducing bubbles. Particulates in the water may create
    undesired acoustic scattering effects. Deionized water is
    recommended to reduce electrical coupling in strong
    conducting fields.
2. When measuring with membrane hydrophones, use high
    resistivity water. We recommend a minimum of 200 kΩ -cm
    because conducting water becomes a capacitive shunt
    across the device, which affects low frequency readings.
    Fresh deionized or distilled water is recommended because
    it typically has a high resistivity of 1 MΩ-cm or more.
    Routine checks of conductivity will ensure accuracy in the
3. Ensure the water temperature is stable to minimize
    measurement variation caused by changes from the sound
4. Minimize electrical interference from other sources which
    may create spurious signals in the measurements.


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