> > An older reference is dBm, which is 1 mW into 600-ohms > "dBm" is a power measurement in decibels, referenced to 1 mW; without any specified impedance. In RF work, "dBm" is usually referenced to a 50 ohm impedance; except for CATV and microwave baseband, which is referenced to 75 ohms. --Duncan, K2OEQ