HS/70

The HS/70 is a helicopter dipping sonar that, with slight modifications, can be installed in small surface ships. The HS/70 has three basic methods of operation: active detection, passive monitoring and submarine communications. Passive monitoring uses only the receiving equipment to detect signals within a pre-determined frequency mode. Only the azimuth of a perceived threat may be targeted in this mode. In the third mode, reduced-power sound waves are transmitted and coded for...