VH4x-XPD Series Hydrophones

The VH4x-XPD series hydrophones consist of the VH40-XPD, the VH41-XPD, and the VH42-XPD. These transponding hydrophones can receive and transmit signals and are used with transponding tags, such as the Chat tag, and are primarily used with the VR28T Tracking System.

Each VH4x series hydrophone has a four element array, one element for each horizontal direction: bow, aft, starboard, and port, and a transponding unit mounted on the bottom. The photo is a view of the bottom of the hydrophone, showing the transponding element and two of the hydrophone elements.

The difference between the VH40-XPD, the VH41-XPD, and the VH42-XPD is the frequency ranges in which the hydrophone operates. These frequency ranges are listed below:

VH40-XPD: For use between 50kHz and 76kHz (resonant at 69kHz).

VH41-XPD: For use between 34kHz and 50kHz (resonant at 50kHz).

VH42-XPD: For use between 28kHz and 33kHz (resonant at 33kHz).