How The Fishfinder Works; Raymarine Sonar Modules - Raymarine a series Installation And Operation Instructions Manual

17.1 How the fishfinder works

The fishfinder application uses a sonar module and a suitable
sonar transducer. The sonar module interprets signals from the
transducer and builds up a detailed underwater view.
The transducer is located on the bottom of the boat, it sends
pulses of sound waves into the water and measures the time it
takes for the sound wave to travel to the bottom and back. The
returning echoes are affected by bottom structure and by any
other objects in their path, for example reefs, wrecks, shoals
or fish.
Colors are used on the display to indicate the strength of the
returns. You can use this information to determine the bottom
structure, the size of fish and other objects in the water, such
as debris or air bubbles
Note: Some transducers include additional sensors to
measure water temperature and/or speed.
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17.2 Raymarine sonar modules

The table below lists Raymarine's sonar modules and the
technology used.
CP450C
CP100
Dragonfly (internal sonar)
a68 / a78 (internal sonar)
CP300
a67 / a67 Wi-Fi / a77 / a77 Wi-Fi
(internal sonar)
c97 / c127 (internal sonar)
e7D / e97 / e127 (internal sonar)
Note: The Fishfinder application menu options and settings
will differ depending on the type of sonar module in use.
CHIRP — ClearPulse TM
CHIRP — DownVision TM
CHIRP — DownVision TM
CHIRP — DownVision TM
ClearPulse TM
ClearPulse TM
ClearPulse TM
ClearPulse TM
New a Series / New c Series / New e Series