Drifting pulsations in a solar radio noise storm

Pulsations in the noise storm of solar radio emission are analyzed. The experiments were performed at the IZMIRAN radiospectrograph on November 20,1975. Dynamic spectra in the ranges of 45 to 90, 93 to 186, 180 to 230 MHz, circular polarization of radio emission at 74 MHz, and radioemission flux at 207 MHz were measured. All the pulsations have a distinct frequency drift. The main characteristic feature of pulsations in the noise storm under consideration is a successive change in the direction of the frequency drift. Parameters of separate pulsatios do not depend on the direction of the frequency drift. The low-frequency boundary of pulsations with both signs of the frequency drift is near 50 MHz. The results obtained permit to make a conclusion that in the given case, pulsations are of a solar origin