Abstract: In an embodiment, an apparatus and method capable of determining the time and location of a projectile's impact is disclosed. In another embodiment, an apparatus and method capable of determining the time and location of a projectile's impact as well as the direction from whence the projectile came is disclosed.

Abstract: A transducer is described especially for use in providing acoustic transmission in a borehole. The transducer includes a multiple number of magnetic circuit gaps and electrical windings that have been found to provide the power necessary for acoustic operation in a borehole while still meeting the stringent dimensional criteria necessitated by boreholes. Various embodiments conforming to the design are described. Moreover, the invention includes transition and reflector sections, as well as a directional coupler and resonator arrangement particularly adapted for borehole acoustic communication.An acoustic communication system is described especially designed for use in providing acoustic transmission of information in a borehole. The communication system comprises a surface transceiver and at least one downhole transceiver. The surface transceiver operates in conjunction with a host computer that sends commands to the downhole transceiver.