Electromagnetic Interference Measurements at 900 MHZ on 230-KV and 500-KV Transmission Lines

Electromagnetic interference (EMI) measurements in the 900 MHz range from a 230-kV and 500-kV transmission are reported. The paper presents measurements made from the tower hardware and midspan conductors in both fair and foul weather conditions. A sensitive meaurement system consisting of a high-gain parabolic antenna and a low-noise preamplifier were employed to gather EMI data from four different detectors and two bandwidths. The results are then compared with predictions based on extrapolation of previous data gathered at frequencies below 200 MHz.