In addition to the frequency selector and the RBW selector, you can also control the frequency range and display detail using the keyboard and mouse.

Mouse

Mouse cross

Moving the mouse cursor over the spectral chart displays a white cross formed by a horizontal amplitude line and a vertical frequency line. The lines have a description at the ends in the units of the given axes. The cross is a practical helper for quickly comparing amplitudes or finding the frequency of specific amplitudes. The detail of the displayed frequency value depends on the total width of the frequency spectrum.

Click and drag

Using the mouse in the spectrum area allows you to make quick cuts of the detail of the currently displayed spectrum. We start by left-clicking on the lower desired frequency, holding and dragging to the right, and then releasing the left button on the upper desired frequency. This way, you can zoom in on the section of the graph that interests you at any time. The spectrum analyzer automatically adjusts the new lower and upper frequency limits and also sets the optimal resolution bandwidth (RBW). You can adjust this later at any time as needed.

If you use the same click and drag movement on the X-axis label area (the frequency axis with the Frequency (MHz) label), you can drag while holding the left mouse button to move the spectrum graph to the left or right. Each time you release the mouse button, a new lower and upper frequency is set.

Signal selection and measurement

Drag with the LEFT mouse button in the spectrum chart to select a range for zoom-in. You cannot zoom in HSR replay mode.

Drag with the RIGHT mouse button in the spectrum chart to select a signal for time-domain I/Q analysis. The selected bandwidth is limited to the maximum bandwidth supported by HackRF in live mode (20 MS/s). In I/Q replay mode, the selection can use the full recorded WAV/PCM/CU8 bandwidth.

Double-click the RIGHT mouse button to select a 20 MHz bandwidth around the center frequency. In WAV/PCM/CU8 replay mode, double-click selects the full replay bandwidth.

Hold CTRL and drag with the LEFT mouse button to measure the difference between two points on the chart. The measurement shows both delta frequency on the X axis and delta amplitude on the Y axis.

Hold SHIFT while dragging with the LEFT or RIGHT mouse button to make selection from the signal center frequency.

Hold ALT while dragging to bypass automatic snapping to rounded frequency values or compressed range boundaries.

Mouse wheel

The wheel allows you to make very fast zoom-ins/zoom-outs of the graph details. Moving the wheel forward zooms in on the graph and sets the frequency center where the mouse cross was placed. Moving the wheel backward zooms out on the graph, while the frequency center remains the same. Using the mouse wheel sets the new lower and upper frequency limits and sets the optimal resolution bandwidth (RBW). You can adjust this later as needed at any time.

Keyboard

Using the keyboard on the spectrum is only possible after setting the mouse focus on the spectrum chart (for this, just left-click anywhere on the spectrum). Now you can use the keyboard arrow keys (left, right). Each key press moves the frequency range backward - forward to set the new previous or next frequency range. 10% overlap preserves partial frequency ranges at the boundaries, so that you do not miss these frequencies. The function of keyboard arrow keys correspond to the function of clickable arrow keys on the control panel.