Due to the difference principles, technologies, and structures of the underwater transducer
or hydrophone , the transmitted signal of existing underwater acoustic modem such as the Link Quest's UWM Series is not an omni-directional signal but a directional signal with a certain beam width.
An Argotech model 210 underwater transducer (positioned at the center of one end of the pond) produced a pure tone of 164 dB [micro]Pa/@ 1 m at a frequency of 100 or 300 Hz.
Underwater transducers were also prone to leaks and malfunctions, and had to be replaced on several occasions by Argotech during the experiments.
Typical models include low-frequency underwater transducers
, acoustic horns and waveguides, stepped shafts and electromagnetic waveguides with variable cross-sections.
Exponential transducers for rough surfaces, as well as underwater transducers
are also available.