Anything higher than -70dBm is considered good signal power, but what would be the theoretical “maximum” value that you could achieve/have seen “in the wild” on regular consumer hardware (e.g. smartphones) and an average cell tower, without any data transfer issues? A measurement that would be read out if you were to hold a phone out standing very near an average LTE cell tower? 0 dBm? Probably too high. -30?
The signal level is 0 in the radio itself. As soon as you go out a cable to an antenna you have loss. That’s why the value is always negative.
I’ve seen RSSI values as good as -26 using a good LTE router with a high end outdoor antenna very close to a tower.
not necessarily though, if the signal level is 0 and the radio’s transmit power were to be doubled, the signal level would be 3.
each time the signal is doubled, the value increases by 3, each time the signal is halved, the value decreases by 3
the signal is significantly weaker after going through the air etc, so it is negative