A study of 13 wave events having 10- to 45-s periods observed by the synchronous satellite ATS 1 in the morning sector reveals that these events, which have been called band-limited pulsations and are thought to be related to Pi 1, appear actually to be Pc 3. Digital power spectral and coherency analysis was used to determine the characteristics of the wave activity. The average peak frequency of the vents (~0.04 Hz) and their generally narrow banded nature correspond closely to the characteristics of Pc 3. The local time distribution of the vents (peaking at 0900 LT) and their less than complete association with substorms also correspond more closely to Pc 3 characteristics. The orientation of the major axis of the polarization ellipse for these events was predominantly azimuthal, which agrees more closely with the east-west polarization of Pi 1 observed on the ground. However, some examples of radial orientation were observed in the satellite data.