Standard deviation of the δS_ν distribution normalized by that at 150 MHz at the shock-front for the ℳ_i = 3 case at all frequencies for the ℳ_cr = 1 fresh injection model at t = 187.4 Myr. We show the result for three different numerical resolutions. The first column shows the results from the original maps and the second column the results from the smoothed maps, similarly to Fig. 8.