Metre wavelength solar radio bursts with periodic modulation

Observations of solar radio bursts in the frequency range 125-150 MHz are described. It is found that their properties are consistent with those observed for similar bursts in the 30-55 MHz range, except that all, rather than just a small proportion, showed periodic intensity maxima or fringes in the frequency-time plane. Fringe separation Δf was found to change with frequency between 30 and 150 MHz, a result inconsistent with Faraday rotation as the cause of the fringes