The IPEI payload onboard ROCSAT-1 has observed many well-known low-latitude ionospheric phenomena at 600 km altitude, such as the diurnal variations of ion density, composition and temperature. The equatorial spread F events, such as bubbles and blobs, together with the flow variations are also recorded with an unprecedented high time resolution at a sampling rate of 1024 Hz. The satellite-borne data on power spectral density of the equatorial spread F event on the transitional scale (10-100 m) is presented here for the first tiem. The local-time and longitudinal variations of the vertical drift velocity in th dawn sector indicated strong hemispheric asymmetry.