Raymarine H6, Owner'S Manual

Page: 165 / 192

Appendix C: Sonar 151
Factors that can impair an image
Although weaker than bottom or other echoes, your sonar picture may be
impaired by echoes received from floating or submerged debris, air bubbles or
even your boats movement. This is known as ‘background noise ‘or ‘clutter’ and is
controlled by the gain modes (gain, color gain and TVG). Raymarine recommends
that you allow your system to automatically control the ideal sensitivity level
based on depth and water conditions. You can however adjust these settings
manually if you prefer.
Range and shift values
By default, the sonar automatically adjusts the display depth range, selecting the
shallowest range that keeps the bottom in the lower half of the display window.
Alternatively clicking the
RANGE button lets you select the maximum depth
displayed on the scrolling bottom and A-Scope images. You can also shift the
image up or down within the current range. When you select Auto Range, the shift
adjustments is reset to zero. Range adjustments affect all sonar windows.
The range setting is indicated in the sonar status bar. The following range and shift
values are available:
Range
Index
Range
(feet)
Shift
increment
(feet)
Range
(fathoms)
Shift
increment
(fathoms)
Range
(meters)
Shift
increment
(meters)
1 5 1 1 1 2 1
2 10 2 2 1 4 1
3 15 5 3 1 6 2
4 20 5 4 1 8 2
5 30 10 5 1 10 2
6 40 10 8 2 15 5
7 50 10 10 2 20 5
8 60 20 15 5 25 5
9 80 20 20 5 30 10
10 100 20 25 5 40 10
81238_1.book Page 151 Thursday, September 16, 2004 2:49 PM