The physical mechanisms that cause daytime 150-km echoes at equatorial latitudes are still puzzling. However, there is a general consensus that the radar signals coming from this altitude region should present a narrow spectra (1000 m s-1). On the other hand, the time and altitudinal characteristics of these off-perpendicular observations are the same as those presented by the so-called 150-km echoes. Moreover, the off-perpendicular echo strengths are several orders of magnitude weaker than perpendicular echoes. Our preliminary interpretation of these results suggests that the spectra of these signals are controlled by ion (electron) dynamics when they are observed off-perpendicular (perpendicular) to B.