The Hydrophone Verification and Re-Calibration Unit can be used for all Seamap hydrophone variants. A short jumper cable is provided in order to adapt between 4 pin and 2 pin hydrophone types. The unit has the capability of reading from and writing to the EEPROM inside the 4 pin hydrophones. The USB-A connector with standard pin out allows programming of the processor and uploading and downloading of data.

The unit is simple to operate. The user plugs in the test hydrophone and sets the mode to automatic or manual. In automatic mode the calibrator automatically calibrates the hydrophone with a preset program and stores the data in the memory and also in the hydrophone EEPROM. The automatic mode can be programmed via the USB interface. In manual mode the user selects a frequency and pushes the power switch to get a readout response. The user controls include a potentiometer knob to control frequency for the manual mode, and a push button switch (on only while being pushed), for running the manual signal, or starting the automatic calibration.

The Hydrophone Verification and Re-Calibration Unit has a display for frequency shown in Hertz, and a display for voltage given in dBV. The latter will typically be given in dBV referenced to the internal reference and will therefore be a measure of the hydrophone’s sensitivity. In the manual mode, when the unit is not connected to another device, the display will show sound pressure level in the calibrator, such that the user can determine if the system is giving the correct output.

Power is supplied via battery which can be recharged via the USB port. The handheld unit is supplied in a carry case.