Dynamic spectrum and one-dimensional projection of radio images in the east–west (EW) and north–south (NS) directions. (a) Example dynamic spectrum of a type IV radio burst that occurred on 14 June 2012 from the Nançay Decametric Array (NDA; Boischot et al. 1980) and e-CALLISTO Birr spectrometer (Zucca et al. 2012). (b), (c) One-dimensional projection of 150 MHz radio images from the NRH in the EW and NS directions, respectively, for the same period as the dynamic spectrum in (a).