Navman Datahelm 8120 Installation And Operation Manual page 36

When to use Mixed
The Mixed frequency combines the 200 kHz
and the 50 kHz echoes on one sonar window,
filling in detailed echoes in the centre of the
sonar cone.
When to use 50/200 kHz
Operating the Instrument at both 50 kHz and
200 kHz simultaneously on a split window
can be very useful when operating in
shallow to medium water, typically less than
500 ft (150 m), because the 50 kHz section
of the window shows the general area,
while the 200 kHz section can be viewed
simultaneously for a more detailed look at
any interesting feature.
To use 50/200 kHz, select the Split 50/200
window (see section 9-4).
36
A
B
A Narrow angle, more detailed 200 kHz cone
B Wide angle, less detailed 50 kHz cone
8120 Installation and Operation Manual
B