Spectra of four different locations of 3C 273 using data from Perley & Meisenheimer (2017). The locations are indicated by circles in the 30–80 MHz images in the top left panel and the spectral index map in the top right panel. Overplottedare JP spectra (Jaffe & Perola 1973), shifted to match the spectra. This means that it is not possible to extract an estimate of the age or magnetic field from this data alone. The VLA images and LOFAR LBA image are all smoothed to a similar circular beam before the flux densities in the indicated regions is determined. The flux densities tend to exceed the flux density given by the JP model.