Low Frequency Range Tracking Transducer

NUWC Division Newport has been developing a Low Frequency Range Tracking Transducer (LF RTT) utilizing 2nd generation single crystals operating in the 32-mode to provide tracking pinger transmit capabilities to small-diameter vehicles for which current PZT-based pinger transducers are too large. These transducers reduce the volume and weight by 90% compared to legacy devices while maintaining the capability to transmit in the K-, B-and D-bands at the required source levels, beam patterns and bandwidths. A total of thirteen LF RTT prototypes have been built and characterized by NUWDIVNPT. Six of these transducers were characterized at NUWC's Dodge Pond facility in March, August and September of 2014. In this paper, it will be shown that the electrical and acoustic properties of these seven prototypes are virtually identical. These LF RTT prototypes demonstrated the capability to meet beam pattern as well as source level requirements in the B-and D-bands within the power and voltage ranges available from existing MK84 pinger electronics. The transducers displayed receive sensitivities 5 to 25 dB greater than required in all bands. The transducers also demonstrated the capability to transmit operationally required pulse lengths and duty cycles for 30 minutes with minimal heating both in air and in water. It was also determined that the projectors were capable of meeting or exceeded threshold acoustic power requirements.