8-5 Range
Range is the vertical depth displayed on the 657 sonar display. For example, if the range is 100 m, then the sonar display shows depths between 0 and 100 m. The range is displayed at the bottom, right corner of a sonar display.
The 657 has two range modes:
Auto: The 657 adjusts the range automatically so that the bottom of the water is always shown at the bottom of the display. Auto range is recommended for normal operation.
To set Auto mode:
1Go to a sonar display (see section 9).
2Press 
, select Range and select
Auto.
Manual: The 657 does not adjust the range automatically. If the bottom depth is below the range, the bottom will not appear on the display. Manual range is useful if the bottom depth changes rapidly, because Auto range will cause the display to change range frequently.
To set Manual range or to change the range:
1Go to a sonar display (see section 9).
2Either press 
to increase range or
press 
to decrease range
! WARNING
Use the Auto range when learning to use the 657 or when travelling at speed.
Zoom range and offset
The sonar Zoom and Bottom displays can show a magnified part of the range (see sections
38 | Northstar Explorer 657 Installation and Operation Manual |