We are well known as one of the global leaders in the manufacture, testing and calibration of ultrasound measuring equipment and were asked whether we could calibrate one of the 1mm needle hydrophones at well below the normal working frequency range.
Working together with Neptune Sonar who manufacture sonar equipment, the hydrophone was deployed on the site in Kelk, Yorkshire. Here sonar equipment is often tested outdoors as well as under laboratory conditions.
Such standard needle hydrophones are designed typically to measure ultrasound in the 500 kHz to 50 MHz frequency range. Precision Acoustics were able to calibrate the equipment in Kelk under the recent winter conditions and were able to obtain data as low as 30 kHz demonstrating both the exceptional performance characteristics of the needle hydrophones and the exacting requirement to calibrate the equipment.
The image below shows Adam from Precision Acoustics venturing out onto the raft where the laboratories are located.