Sonotronics - Model DH-4 - Directional Hydrophone - Manual

The DH-4 provides the greatest range and precision in locating transmitters from 30kHz to 100kHz. The parabolic reflector provide 16db of gain over a comparable omnidirectional hydrophone, and yields a calculated DI of nearly 25db, reducing the effect of environmental noise. The DH-4 is the primary hydrophone for manual/active tracking.