Recently the spatial resonance rnechanism of gravity waves and plasma drifts was assumed to be responsible for the modulation of the macroscale structure of the equatorial spread-F (Beer, 1974; Rottger, 1975a). To check this idea, RTI-records of the Jicarnarca radar (Woodrnan and La Hoz, 1976) which indicate quasi-periodic layers of spread-F irregularities were evaluated.