Simrad EC150-3C, Installation Manual, Page: 56 / 150

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Electrical self noise
Electrical or electronic self noise is picked up or generated in any other part of the
equipment than the transducer.
Hum picked up by the transducer cables or picked up from the power supply is usually
the most common source of electrical self noise. At higher frequencies – where rather
wide bandwidths are necessary – the noise from components, transistors or other
analogue electronic may be a limiting factor.
Related topics
Acoustic noise, page 52
Installation summary, page 30
Ambient noise
Ambient noise is usually not a limiting factor to the performance of sonars and echo
sounders.
The ambient noise may be split up as follows:
•
Sea noise
: Air bubbles, seismic disturbances, waves, boundary turbulence, etc.
•
Biological noise
: Fish, mammals
•
Man made noise
: Other vessels, interference
•
Precipitation noise
: Heavy rain or hail
In some areas, where many vessels operate together, the engine and propeller noise from
other vessels may be disturbing. Interference from hydroacoustic instruments located
in other vessels may also be a limiting factor. The sea noise depends on the weather
conditions. In bad weather the sea noise can be quite high due to the waves.
Related topics
Acoustic noise, page 52
Installation summary, page 30
Fishing gear noise
Whenever your fishing gear is in use, it will create noise.
A bottom trawl, for instance, is a considerable source of acoustic noise. Still, this
noise from the fishing gear will seldom be a limiting factor for hull mounted sonars or
echo sounders. However, for operation of a catch monitoring system or a trawl sonar,
with the transducer placed on the trawl, the gear noise is one of the main contributors
to the noise level.
Simrad EC150-3C Installation Manual