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System diagram

The Simrad FX80 system comprises a Processor Unit (computer), the Bridge Control Unit, and the two subsea units.

This is a simplified system diagram. Power cables, uninterrupted power supplies and external interfaces are not shown.


A. Colour display (two displays may be used)
B. Processor Unit (personal computer)
C. Bridge Control Unit
D. 3rd wire (commercial, not provided with FX80 delivery)
E. Trawl Deployment Unit (holds the Communication Hub and the Sonar Head)
F. 4th wire
G. FX80 Camera Unit (video camera and lamp)


The number of displays must be chosen to fit the preferences of the crew. Many users prefer separate displays for the trawl sonar and the live video feed. Colour displays are not included in the standard delivery. These are commercial items that can be purchased locally.

Winch and third wire

The winch system on the trawl deck and the 3rd wire cable must be provided by a third party manufacturer.

Camera Unit

The Simrad FX80 Camera Unit (containing the camera and LED lamp) can be remotely mounted on the trawl up to 600 meters from the headrope. In these cases you will need for a winch to handle this “4th wire” cable. This winch needs to be installed on deck in a practical location as the (up to) 600 meters of cable will be spooled entirely off and then back on with each tow. You will also need a rope that do not stretch (for example Kevlar) to protect the cable.

In applications where the camera is located on a kite or at the headrope there is no need for this cable and winch.

The "4th wire" cable is supplied with the Simrad FX80 delivery. The required length can be decided at the time of purchase, or lengths can be added at a later time. The system itself is not set for any particular length.