If you use a receiver like the RTL-SDR, the measured signal power depends on multiple parameters, like the tuner IC, the gain mode and level, etc.
S9 relates to a physical value of -73 dBm power measured at the receiver input.
The values shown on the S-meter currently are in dB, not dBm, so it doesn't tell this physical value, and can only be used to relate the power of different signals to each other.
To be able to tell the input power correctly, you have to use the manual gain mode, and you need to make measurements to calibrate your SDR to a receiver with a correct scale or a signal generator.
I think I will need to add another parameter to config_webrx.py which will tell the offset to use while calculating the power at the receiver input.
You will be able to measure this offset and then set it in the config.
If you use a receiver like the RTL-SDR, the measured signal power depends on multiple parameters, like the tuner IC, the gain mode and level, etc. S9 relates to a physical value of -73 dBm power measured at the receiver input. The values shown on the S-meter currently are in dB, not dBm, so it doesn't tell this physical value, and can only be used to relate the power of different signals to each other. To be able to tell the input power correctly, you have to use the manual gain mode, and you need to make measurements to calibrate your SDR to a receiver with a correct scale or a signal generator.
I think I will need to add another parameter to
config_webrx.pywhich will tell the offset to use while calculating the power at the receiver input.You will be able to measure this offset and then set it in the config.