(A) Real data from NenuFAR observations. The colour corresponds to different frequency ranges of 5 MHz. (B-G) Corresponding periodograms of the S/N of the LS power (noted S/N(LS))for seven frequency ranges averaged on a 5 MHz bandwidth: (B) [8, 13[ MHz, (C) [13, 18[ MHz, (D) [18, 23[ MHz, (E) [23, 28[ MHz, (F) [28, 33[ MHz, (G) [33, 38[ MHz. The 95% confidence level is also shown in the LS periodograms.