Solar radio observations at 10-30 MHz have been carried out recently using radio telescopes UTR-2 (world's largest radio telescope at decametric wavelengths near Kharkov, Ukraine) and Uran-2 (Poltava, Ukraine). High sensitivity and time resolution of these observations allowed revealing many new interesting features of the coronal radio emission (V. N. Melnik et al., AIP Conf. Proc., 1206, 2010, pp. 427-432). Results of these observations can be used for studying coronal processes and remote coronal diagnostics. Of our particular interest in the present paper are coronal radio bursts at 23-29 MHz with drift rates implying the emission sources propagating upward with velocities ∼ 108 cm/s. We discuss such radio bursts and propose a feasible generation mechanism for them. © 2015 International Union of Radio Science (URSI).