NorthStar Navigation NorthStar 8000i - Manual (Page 106)

106 Northstar 8000i Operation Manual
2. The
Auto Mode button shows the current setting. Select the button
if you want to change to another setting and a drop down list appears.
There are three choices:
ƒ Fishing - the range and gain settings are automatically adjusted to
suit fishing conditions.
ƒ Cruising - the range and gain settings are automatically adjusted
to suit cruising conditions. Use this when you're traveling at speed.
ƒ Manual - you can change the range and gain settings yourself. The
sounder will store your most recent settings and use them until
you change them again.
3. Select the new setting. The new setting is applied immediately and
stays until you change it again.
NOTE: If you are operating the sounder automatically in Fishing or Cruising mode
and then change the gain or gain threshold settings yourself, the sounder changes
to Manual mode.
16.10 When to use 50 kHz, 200 kHz, or mixed frequency
50 kHz is useful in deep water, typically greater than 500 ft (150 m) because it
produces a good overview of area. 50 kHz generates a sonar cone that spreads
over a wide, deep area of water with minimal loss of the return signal, but gives a
lower definition display that is more prone to shadows than the 200 KHz
frequency. This means, for example, that a small group of fish close to the bottom
might be shown as a single object, and fish very close to the bottom might not be
shown at all.
200 kHz is good in shallow and medium water, typically less than 500 ft (150 m),
or while you're running at speed because it reduces noise from turbulence. It
generates a narrow sonar cone that returns excellent detail over a small area. This
can be useful if you're trying to identify the type of bottom and/or locate
individual fish. It's also the best choice for reducing shadows when you're fishing
in areas with hollows, rocks and ledges. 200 kHz is the default.
Mixed - combines both frequencies on one display screen. This can be useful if
you're not getting good displays from a single frequency, because it uses the best
return signals that are available from either frequency. However, the mixed
frequency produces a much slower scroll speed compared to a single frequency.