Humminbird Onix Opeartion Manual page 237

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 2D Sonar Overview: 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. See Set up or Change Transducer Settings for details.
Sonar View (Cross Touch, 2D Sonar)
frequency menu
237 Humminbird Network Setup