Dockside In Situ Measurements on SQS-26 Sonar Transducer with NRL Large Nearfield Calibration Array

The results of dockside in situ source level, sensitivity, transmit beam pattern and receive beam pattern measurements with the large Naval Research Laboratory NRL Nearfield Calibration Array NFCA on the SQS-26 CX sonar transducer as installed on the USS BLAKELY 1072 are described. These nearfield technique measurements are compared with computed farfield results and with classical farfield technique measurements performed on the same type sonar transducers reported by other authors. On the whole, the comparison agreement is fair for source level, sensitivity and receive beam pattern measurements. However, the comparison of the transmit beam patterns are in sharp contrast. Some previously reported results and some unpublished measurements with the NFCA on large experimental transducers and on a quarter sector section of the BQS-6 submarine sonar transducer are included in Appendix B that show experimental verification of the nearfield calibration technique as applied with the NFCA.