The nature of electrojet irregularities responsible for daytime VHF scintillations at 41 and 140 MHz observed at Huancayo, Peru, has been examined by conducting a study of simultaneous scintillation measurements, ionograms, and 50-MHz oblique radar backscatter. It is found that the times of onset and decay of VHF scintillations correspond closely with the times of onset and decay of type 2 irregularities identified by the radar as well as Esq echoes on ionograms, indicating thereby that type 2 irregularities cover the scale size range of at least 1 km to a few meters. By assuming a three-dimensional irregularity power spectrum of spectral index 4 and an outer scale dimension of 2 km the range of daytime scintillations at 41 MHz is shown to be consistent with irregularity amplitudes of approximately 5--15% for an ambient ionization density of 1011 m-3. |