Integrated radio continuum spectra of the SNR G338.3−0.0 obtained from the flux density values listed in Table 2 (Col. 5). The dashed line is the best fit to the flux density measurements at frequencies higher than 235 MHz, which gives an integrated spectral index α =  −0.47 ± 0.05. The solid line is the fit to the data using Eq. (1), which takes into account a low frequency turnover due to absorption by foreground thermal gas. This method yields a global spectral index for G338.3−0.0 α =  −0.51 ± 0.06.