10
Calibration
There are two aspects to calibration: the hydrophone and the remora gain. The system
gain is calculated as Recorder Gain + Hydrophone Sensitivity.
Typical hydrophone sensitivities are -211 dBV/uPa.
Loggerhead can perform a reference calibration if required.
The recorder has two gain settings:
Low: 21 dB gain (~190 dB re 1uPa clip level)
High: 33 dB gain (~178 dB re 1uPa clip level)
In most cases the high gain setting is desirable.
Internal Calibration Signal
Each recording starts by playing internal electrical calibration tones.
These signals are 30 uV RMS in amplitude, and can be used to monitor the electrical
calibration of the recorder.
