Systems, software, devices, and methods are described for an RFID reader system to communicate with RFID tags. RF energy encountered in conjunction with using a selected channel is detected and used to adjust a waveform shaping parameter. RF waves can be transmitted from the reader to the RFID tags and RF waves can be backscattered from the RFID tags. At least some of the RF waves transmitted to or backscattered from the RFID tags have a waveform with a shape according to the adjusted waveform shaping parameter.