Signature of Man-Made High-Frequency Radio Noise

This paper expands the single sloping line labeled ?man-made noise? in existing atmospheric radio noise predictions. Data taken from the Puget Sound (Seattle) area are developed to show spectral (0.1-10 MHz) and spatial (1-100 miles) man-made radio noise distributions. The effects of soil/saltwater conductivity contrasts and receiver elevation above ground are also considered. Methods of predicting noise contributions from both nearby cities and electric trunk lines are presented.