I know that the Noise Floor depends on the Bandwidth and in the datasheet from Semtech an1200.22, there is the following equation to calculate the Noise Floor:
If I use 125kHz for the Bandwidth (B), I get the following result: -122.9 dBm
When I receive LoRa packets at the Gateway and calculate the average measured Noise Floor, by “RSSI - SNR” i get the following result: -100dBm more or less. This creates a gap of 22.9 dB.
Where I live we use the 915MHz, if I use the whole band for my Bandwith “928 MHz - 902 MHz = 26 MHz = B”, and calculate the Noise Floor I get -99.78 dBm, that is much closer to the measured Noise Floor.
Is what I do correct? Can someone refer an article or book explaining this?