Comparative Radio Noise Levels of Transmission Lines, Automotive Traffic, and RF Stabilized Arc Welders

Radio interference data that have been measured throughout the frequency range of 30 Hz to 1 GHz on power transmission lines, automotive traffic, and RF stabilized arc welders by many investigators have been assembled, converted to a common system of units, and collectively plotted. The resulting composite presentations permit an assessment of the relative interference levels produced by the three types of radio noise sources. It is concluded that below 25 MHz, lower voltage transmission, lines and RF stabilized arc welders are the major incidental radio noise sources when the observer is within 100 feet of the source. Above 40 MHz, automotive traffic and lower voltage transmission lines are the major radio noise sources with neither appearing to be consistently the greater when an observer is within 50 feet or less of the source.