I just listen (with an SDR, I never got a HackRF because I don't transmit). Where I live I can see planes on approach to SFO and can cross-reference flight cod

I just listen (with an SDR, I never got a HackRF because I don't transmit). Where I live I can see planes on approach to SFO and can cross-reference flight codes on the radio with planes that I can see flying by and on flightradar.