The specification stipulates performance requirements for radio interference measuring apparatus including the associated standard artificial mains network. It is also specifies the requirements that have to be met in the measurement of noise voltages at the terminals of interference producing apparatus and in the measurement of noise fields from such apparatus. The specification is divided into four parts as follows: Part I: Measuring set. Part II: Measurement of radio-noise voltages. Part III: Measurement of radiated radio noise. Part IV: Methods of measurement of various types of interference-producing apparatus. The appendices to the specification give additional information on the fundamental characteristics on which the requirements are based. Parts II and III lay down general requirements for the measurement of noise terminal voltages and noise fields respectively. Detailed requirements for the measurement of interference produced by various apparatus are specified in Part IV. This part is divided into sections@ each dealing with special requirements for the measurement of interference produced by a particular type of apparatus@ for example??Section 1 deals with domestic appliances. Sections dealing with other types of apparatus will be added as the need arises and when agreement is reached on the method of measurement. Note: The requirements of the specification shall be complied with at all frequencies and for all levels of voltage or field strength within the range of the measuring equipment.