The plugin will be built only if the [HackRF host library](https://github.com/mossmann/hackrf) is installed in your system. If you build it from source and install it in a custom location say: `/opt/install/libhackrf` you will have to add `-DHACKRF_DIR=/opt/install/libhackrf` to the cmake command line.
If you have the Tx open in another tab and it is running then it will be stopped automatically before the Rx starts. In a similar manner the Rx will be stopped before the Tx is started from the Tx tab.
Use the wheels to adjust the sample rate. Left click on a digit sets the cursor position at this digit. Right click on a digit sets all digits on the right to zero. This effectively floors value at the digit position. Wheels are moved with the mousewheel while pointing at the wheel or by selecting the wheel with the left mouse click and using the keyboard arrows. Pressing shift simultaneously moves digit by 5 and pressing control moves it by 2.
- if decimation n is 4 or lower: Fc = SR/2^(log2(n)-1). The device center frequency is on the side of the baseband. You need a RF filter bandwidth at least twice the baseband.
- if decimation n is 8 or higher: Fc = SR/n. The device center frequency is half the baseband away from the side of the baseband. You need a RF filter bandwidth at least 3 times the baseband.
<h3>9: Rx filter bandwidth</h3>
This is the Rx filter bandwidth in kHz. Possible values are: 1750, 2500, 3500, 5000, 5500, 6000, 7000, 8000, 9000, 10000, 12000, 14000, 15000, 20000, 24000, 28000 kHz.