SonarMite BTx/SPx v5.02 © 2016 Lymtech
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Typical Use of the Equipment
The SonarMite Portable Echo Sounder has been designed to provide a portable
instrument that provides the facilities of a „professional‟ sounder at the cost and
performance of a „fish finder‟ device. It is important to recognize what the differences
are between these two types of echo sounder. The „fish finder‟ or leisure craft devices
are primarily concerned with two functions, finding fish in the water column below
the boat by sensing returns from their swim bladders and providing a bottom
tracking/smoothing algorithm to detect average water depth below the boats hull.
Survey sounders are designed to provide a large number of pings with as little
processing of the raw data as possible to define the bottom in as fine detail as
possible. Of major concern in a survey sounder is a narrow beam width to prevent
averaging of the returned signal.
235KHz Active Transducers
The SonarMite uses Active Transducers, these are digital as opposed to analogue
components and use microprocessors to synthesize transmitted frequencies and to
interpret the return signals. The devices incorporate state of the art DSP and filtering
techniques to reduce noise and improve depth tracking. These devices are supplied
encapsulated in resin and have no serviceable parts. The connecting cable to the
transducer carries only low DC voltage and digital I/O, none of the EMC problems
associated with conventional analogue sonar devices apply.
To improve weatherproofing and to avoid connection problems the SonarMite has
two connectors that provide all the I/O required by the device. One of the connectors
also includes a return pin to enable the system to switch on by cable connection rather
than using a switch. Cables to the device can be connected simultaneously (e.g.
Transducer on port 1 and Serial Data Cable on Port 2).
