Results from a VHF backscattering experiment using the Jicamarca incoherent-scatter radar are described for a mesospheric height. The echo power during the day varies intermittently and sporadically over a range of almost 30 dB with a median strength about 4 dB above the incoherent-scatter level. The enhanced echo power is generally associated with a wider autocorrelation function. The autocorrelation function often exhibits a second peak. Vertical and zonal or meridional velocities have been obtained from the complex autocorrelation function using two closely pointed antennas. Long sequences of these velocity measurements have been shown to correspond to internal gravity waves. © 1974.