Example spectra showing the inband spectra of LoTSS. Left panel: a low-luminosity peaked-spectrum source; right panel: a source that deviates significantly from a power-law profile. The legend in each plot communicates the survey data used. The best-fitting generic curved model fit (black) or power-law fit (orange) is shown for each SED, derived from the model-fitting code described by Callingham et al. (2015).