69 kHz Sea Water Range Calculator


This calculator predicts range in typical ocean conditions and is intended to give users a starting point in determining transmitter power, receiver spacing requirements, etc. It is not intended to replace in situ range testing for any proposed receiver deployment. Particularly with VR2 and VR3 listening stations, in situ testing is recommended for any study area in which it is suspected that conditions may vary from the assumptions here. Assumptions include:

Noise Dominated by Sea State:
This is usually a good assumption but, in some situations conditions can be significantly worse due to additional noise from rain, man made sources including boats and sonars and biological sources such as snapping shrimp.

Absorption at High End of Range:
Absorption (losses in excess of normal spreading losses) is an important limiting factor to range at the relatively high frequencies used for telemetry. This varies with salinity, depth and water temperature. The value used in this calculator is at the high end of the range and, as a result considerably greater ranges will be seen in some situations.

Enter Parameters:


Transmitter Power
(dB re 1 uPa @ 1 m)
Receiver Type
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