NorthStar Navigation Echo Sounder NorthStar 491 - Manual (Page 46)

Page 42 491 Echo Sounder Operations Manual
Using the MORE key
Pressing the MORE key accesses the following functions:
• alarms (described in Chapter 7)
• advance speed
• A-scope
• data (numeric and graphic information on the ECHO
screen)
• snapshots (961/962 only)
• video overlay setup (957/958 only)
When the menu function is in use in the 961/962, the ECHO
screen moves every half second, giving the picture a less than
smooth appearance. Press RETURN to go back to the main
screen for a normal smooth appearance.
Changing the advance speed
Advance speed refers to the speed at which the vertical scan
lines move from right to left across the ECHO screen. There
are five advance speeds (plus the STOP setting, which freezes
the advance of all data):
• 2/1 - two identical lines of data are displayed for every
ping
• 1/1 - one line of data is displayed for every ping
• 1/2 - one line of data is displayed for every two pings
• 1/4 - one line of data is displayed for every four pings
• 1/8 - one line of data is displayed for every eight pings
For speeds 1/2, 1/4, and 1/8, each displayed line of data is
averaged over 2, 4, or 8 pings.
To set the advance speed:
1. At the ECHO screen, press MORE, then press ADVANCE
SPD.
2. At the SET ADVANCE SPEED window, keep pressing the
ADVANCE SPD key to select the desired advance speed.
3. Press RETURN to go back to the ECHO screen.