NorthStar Navigation 8000I operation manual Sounder 101

15	The sounder	101
15.1	How the sounder works	101
16	Use the sounder	101
16.1	Display the sounder screen	102
16.2	What does the sounder screen show?	102
16.3	What does the sounder status bar show?	103
16.4	Change the scroll speed	103
16.5	Change the palette	104
16.6	Show/hide the depth value	104
16.7	Show/hide the depth line	105
16.8	Move the depth line	105
16.9	Change the sounder operating mode	105
16.10	When to use 50 kHz, 200 kHz, or mixed frequency	106
16.11	Select 50 kHz, 200 kHz or mixed frequency screen	107
16.12	Select a split 50/200 kHz screen	107
16.13	Select a split zoom screen	108
16.14	What is zoom range and zoom range shift?	108
16.15	Change the zoom range shift	108
16.16	Select a split bottom lock screen	109
16.17	Change the ratio of a split screen	109
16.18	What is the A-Scope?	110
16.19	Show/hide the A-Scope	111
16.20	Change the ratio of the A-Scope	111
17	How to interpret the sounder screens	112
17.1	What are fish arches?	112
17.2	Problems with fish arches?	112
17.3	How to recognize different types of fish	113
17.4	How to recognize and avoid shadows	113
17.5	How to recognize the type of bottom	113
17.6	How the water depth and scroll speed affect the history	113
17.7	Factors that affect the echo strength	114
18	Change the sounder range and gain	115
18.1	What is gain?	115
18.2	Change the gain setting	115
18.3	What is the gain threshold?	116
18.4	Change the gain threshold	116
18.5	What is auto range and range shift?	117
18.6	Turn the auto range on or off	117
18.7	Change the range shift	118
18.8	Change the range	118

10 Northstar 8000i Operation Manual