Long-term data set of radar observations using coherent and incoherent scatter radar sources during 1996-2008 were used to study the trend of low-latitude ionospheric irregularities, also referred to as equatorial spread F (ESF), near geomagnetic equator over Jicamarca, Peru (12°S, 76.9°W, geomagnetic latitude 1°N). Radar signatures are classified on the basis of their structures. The occurrences of radar signatures of the F-region plasma irregularities are highly seasonal and solar cycle dependence. Irregularities are more dominant during December solstice with ~88% of the total night of observations, while the irregularities occurrences are minimum during June solstice with~29% of the total nights of observations. Using incoherent scatter radar observations, the relationships of vertical drift velocities of plasma with the onset of ESF have been studied. Generally, the strong spread...