RBW is fixed at 1.75MHz on the HackRF. But it's the measurement setup as a whole (that is the measurement receiver). The noise floor of this measurement is repr

RBW is fixed at 1.75MHz on the HackRF. But it's the measurement setup as a whole (that is the measurement receiver). The noise floor of this measurement is represented by the visible noise floor at -70dBm. That's a combination of a number of factors. Plus the HackRF has poor dynamic range and only 8 bits sampling which is quite terrible.