We’re doing some pre-compliance tests and want to understand whether our TX power is likely to be limited by the FCC 8 dBm/3 kHz BW requirement. We’d like to go for max power (22 dBm), and have the harmonics taken care of, but will we need to dial our power back to meet PSD? We want to use all the spreading factors at BW of 500 kHz.
Operating with a 500 kHz LoRa BW you should be easily able to meet the 8 dBm / 3 kHz BW at +22 dBm - typically I’d expect to see between ~25 - 27 dBm depending upon SF. WE would recommend using the AVG detector methodologies of ANSI C63.10-2013 for certification measurements, as documented in the Semtech “FCC Best Practices” AN (AN1200.62).
Perfect - Thanks Steve!