Since the levels inantenna technology, in community antenna systems and EMC measurement technology are very low, one uses the dBµV, decibel microvolt as reference level. The reference value for 0 dBµV is 1 µV. 60 dBµV corresponds to 0 decibel millivolts
(dBmV). A direct relationship can be established between dBm and dBµV via the power and the input resistance. According to this, the interference voltage of 1 mW at 50 ohms is 223.6 mV. From this relation one can calculate the relations between dBµV and dBm. 0 dBµV are -107 dBm, 20 dBµV -87 dBm, 40 dBµV -67 dBm and so on.