Vehicular interference radiation measurement technique

The technique described in this paper is classed as a near-field method wherein the measuring probe is located less than 5-feet from the interference energy source. It provides a means for expressing the magnitude of the interference energy in quantitative terms which are independent of the receiver and antenna characteristics as well as the propagation anomalies experienced in the field intensity measurement technique. It is non-critical in setup and involves a minimum of adjustments following the initial calibration procedure. A 20-db improvement in measurement range is available, which enables positive evaluation of the effectiveness of suppression even down to the normal sensitivity threshold of mobile receivers. Each of the principal elements of the measurement system will be described in terms of those characteristics which have a direct bearing on this application. In addition, a brief analysis of the noise spectra will be presented.