The 'Wheel' button switches between the two mouse wheel modes.

title bar area RUN button Display button KEYPAD button QSIR button SERV button CMD button MODE button FILT button AGC button BAND button NB1 button Receiver buttons MRKS button NB2 button Spare button NR button VLOCK button ANF button Wheel button Centre button Memory button RX EQ button reserved button MODE button 2 AGC button 2 FILT button 2 VLOCK button 2 Frequency panel Frequency panel Step DOWN button Step panel Step UP button SQ button BIN button MUTE button S meter panel Volume control Panadapter left Panadapter filter area Panadapter right Frequency bar position adjuster Frequency bar Waterfall display panel Status bar Wheel button

When the 'W' button is off (not green) wheel movements tune the receiver up or down by the step size and keep the display centred on the new frequency. When it's on, the panadapter and waterfall stays where it is and the new frequency is shown to the left or right, if it is within the spectrum width. The tuned frequency can be brought to the central position, at any time, by clicking the 'C' button.