Onwa KF-667 - Manual (Page 13)

2.3.2 Display mode description
200K, 50K (high frequency, low frequency) mode
The sounder uses ultrasonic pulses to detect bottom conditions. The lower the frequency of
the pulse the wider the detection area. Therefore, the 50KHz frequency is useful for general
detection and judging bottom conditions, while the 200KHz frequency is useful for detailed
observation of fish schools.
DUAL frequency mode
This mode provides the 50KHz picture on the left-half of the screen and the 200KHz on the right
half, and is useful for detecting fish schools which have different reflection characteristics with
frequency. For example, a school of tiny fish like minnow returns stronger echoes on a high
frequency compared to a low frequency.
2-2