Humminbird ONIX Operating Manual page 220

Select Frequencies
If you have enabled the full functionality of the transducer, and all beams are enabled (or set to Auto) in Beam Select, you can
display individual frequencies in the 2D Sonar View. See Adjust 2D Sonar Display Settings for more information.
NOTE: If the control head is using a sonar source with only one beam frequency, the frequencies menu will not offer additional
options.
83 kHz
Humminbird Network Setup
Split (Dual) Sonar Mode (2D Sonar)
frequencies menu
220
200 kHz