Jack Douglas asked 5 years ago
I find it a bit confusing that the code expresses “RSSI” as dB. I thought RSSI is a unitless relative value, whereas dB is an absolute. For example, an RSSI of -50 vs -90 is understood to be a poorer quality of signal, whereas the opposite is true for dB? Would it not be more clear to change the Receiver “RSSI” label to “dB”?
From https://www.metageek.com/training/resources/understanding-rssi.html :
“RSSI vs dBm
dBm and RSSI are different units of measurement that both represent the same thing: signal strength. The difference is that RSSI is a relative index, while dBm is an absolute number representing power levels in mW (milliwatts).
RSSI is a term used to measure the relative quality of a received signal to a client device, but has no absolute value.”
Sara Santos Staff answered 5 years ago
Hi Jack.
You are right about the differences between RSSI and dBm.
I know that RSSI measures the relative quality. However, I thought that the LoRa signal strength was in terms of RSSI.
However, it seems that I’m wrong, because the closer to 0 dB, the better the signal quality. So, we’re measuring in dB.
Nonetheless, it is confusing because the functions to get the signal strength use the “Rssi” word: LoRa.packetRssi();
Thanks for letting me know. I’m always learning.
Regards,
Sara