Noise sources
The operational performance of the ST90 system depends on the noise conditions. It is essential that the noise signature is as low as possible.
Vessel noise
The vessel’s hull, rudder(s) and propeller(s) must be thoroughly inspected in dry dock prior to installation.
Roughness below the water-line deformities in the shell plating and protruding obstacles can create underwater noise. These sources of turbulence must be smoothed or removed as best as possible.
Note
It is especially important that the propeller(s) are not pitted or damaged.
Electrical noise
The quality of the vessel’s supply power is crucial to reduce noise. Electrical or electronic self noise is picked up or generated in any other part of the equipment than the transducer. The most common source of electrical self-noise is hum. Hum is typically generated by low-quality power supplies. Cables and sensitive electronic circuitry can easily pick up hum. At higher frequencies – where rather wide bandwidths are necessary – the noise from components, transistors or other analogue electronic may be a limiting factor.