What units are being reported by Apple for AirPort signal strength?
If you run:
cd /System/Library/PrivateFrameworks/Apple80211.framework/Resources<br /> ./airport -I<br /> ./airport -s
You'll get some good info about your wireless setup. I'm guessing that avgSignalLevel and avgNoiseLevel (-I option) are reported in dBm, but when you use the -s option, you'll get a column labeled "Sig" with a different value (this time, it's positive).
So what units are used in the "Sig" column?
And can someone help me understand the meaning of negative dBm? I get that 0 dBm = 1 mW, but I can't really imagine that the received power is less than one milliWatt. So what does a negative value mean, and if it is just a measurement relative to some other baseline value, then what is the baseline?