During work with RF frontend, you often need some tool for indication what you really send data. Usually for such work used spectrum analyzers – expensive measurement units which really cool and informative. And if you don’t have it or left 1000$+ then the cheapest way is a using HackRF as Spectrum Analyzer.
HackRF as Spectrum Analyzer
Mainly it’s pretty simple – check

Don’t forget to check installation guide inside repo’s readme.