Precision Acoustics was asked whether it could calibrate one of its 1mm needle hydrophones well below the normal working frequency range. Working together with Neptune Sonar, the hydrophone was deployed on a site in Kelk, Yorkshire, where sonar equipment is often tested outdoors as well as under laboratory conditions.
Standard needle hydrophones are designed typically to detect ultrasound in the 500kHz to 50MHz frequency range. Precision Acoustics was able to calibrate the equipment in Kelk under the recent winter conditions and successfully obtained data as low as 30kHz demonstrating both the exceptional performance characteristics of the needle hydrophones, as well as the exacting nature of the calibration job.