Prescribes methods of measurement of insertion loss of passive radio frequency suppression filters, which may consist of single elements, such as capacitors, inductors or resistors, or combinations of inductors, capacitors and resistors of either the lumped or distributed types. The methods include those for use in a laboratory or on a production line, utilizing fixed impedance terminations or "worst case" terminations, those to be used in situ or in model installations, and provides for voltage and current loading.