Wideband measurements (100 kHz) of medium frequency atmospheric noise have been made over the past several years in the southwestern United States. In part 1 of a two‐part paper the measurement and data transcription system and the statistical analysis software used to analyze the data are presented. In part 2, representative first‐ and higher‐order statistics and the impact of the data on bandwidth and system performance are described. Measurement results presented in part 1 include the temporal structure of atmospheric noise, the distribution and time variation of the measured average noise power, and comparisons with predictions by the International Radio Consultative Committee (