This thesis aims the design and the realization of a radio noise meter which can be used to measure radio interference of a high-voltage transmission line due to partial discharges like conductor corona. The radio noise meter is the common equipment for radio noise and radio interference voltage measurements. The corona of transmission lines, its characteristics, its effects on radio interference and measurement of corona caused radio noise in the scope of relevant international standards are investigated. A radio noise meter fed by a monopole antenna, centered to 1 MHz with a bandwidth of 4.5 KHz and using a Quasi-Peak detector having 1 ms charge time and 600 ms discharge time is realized. The conductor corona from the radio interference point of view is observed, measured and analyzed with the help of the realized radio noise meter.