Simrad SL 30, Manual

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SL 30/35 Hull Sonar Operators Manual 974-25007001/2.0
Menu and Software Description Page 4.17
Kongsberg Simrad Mesotech Ltd.
Port Coquitlam, BC - Canada
4.19.7 Range Scale and Target Size
When looking at any sonar image you must keep in mind the range scale you are
using, the position of the sonar relative to the target you are looking for, and the size
of the target. For example, a target the size of a beer can will be very small and
probably not visible on a one hundred meter range scale.
4.19.8 Mirroring Effects
If you try using the sonar inside a rectangular tank such as a swimming pool, it is
quite likely that you will see phantom targets outside the tank boundary. This occurs
because the tank walls are hard and smooth and can reflect the sound pulse from
one wall to another and finally back to the sonar transducer. The sound path is
similar to the path of a billiard ball making multiple bounces off the sides and ends of
the table. Although it is not very common, there are occasions when this same
effect will happen in the sea, particularly when near certain large man made
structures. If you see something in the image that doesn't make sense, look at the
geometry or arrangement of the targets and see if a multiple path reflection could
explain the mis-plotted targets.
4.20 HOW TO GET THE HIGHEST RESOLUTION IMAGE
To get the highest possible image quality:
•
Arrange for the sonar head to be absolutely stable in a fixed location
•
Select the slowest possible scan speed
•
If possible, adjust the computer display resolution to 1280 x 1024 and select the
High Resolution mode
•
Adjust the Pulse Length
4.21 HOW TO GET THE FASTEST UPDATE RATE
To get the fastest update rate on a particular area:
•
Select a higher scan speed