A powerful high frequency (HF) electromagnetic pump wave transmitted into the ionospheric F region excites filamentary density irregularities stretched along the geomagnetic field. We present experimental results of small scale (5--15 m across the geomagnetic field) magnetic field-aligned striations (FAS) excited using the Sura HF pump facility, Russia. The FAS were observed by resonant HF scatter in bistatic mode utilizing continuous wave broadcasting transmissions from near Moscow and reception with the UTR-2 radio telescope as well as in nearly monostatic mode using a pulsed radar transmitter of Kharkov National University and reception at UTR-2. The radar scatter showed that the previously observed split Doppler spectra in scattered continuous wave sounding is a result of pump-induced large scale outward radial drift of the FAS during HF pumping. For sufficiently short pump pulses the radial drift reverses from outward during pumping to inward after pump-off as the FAS decay. This drift reversal does not occur after longer pump pulses. The drift speed amounts to 2--4 m/s.