Radio Interference from the First 735-kV Line of Hydro-Québec

Results of radio interference (RI) level measurements on the first 735-kV line of Hydro-Quebec are presented. The cumulative relative frequency of RI levels for the period from October 1, 1965, to July 17, 1966, is studied. An approximation of this curve by three uniformly distributed meteorological conditions and the dis- tribution curve of absolute humidity are presented. An ensuin equation for the evaluation of RI levels in terms of temperature and relative humidity is included. The rate of change of RI levels with the maximum surface gradient on the conductors is reported. Frequency spectra and lateral profiles measured at mid-span are shown. The evaluation of RI levels using a published method is also illustrated.