Radio continuum spectrum for SNR IC 443 obtained from the flux density values listed in Table 2. The filled circle symbols correspond to the new flux density measurements calculated using the VLA data at 74 and 330 MHz presented in this work, the open symbols are for radio observations previously published and, where possible, brought onto the flux density scale of Baars et al. (1977). Solid line represents the linear fit to the flux density values excluding that at 10 MHz, which produces a spectral index α =  −0.36 ± 0.02 (S ∝ ν^α). Dotted line shows a fit to all of the plotted values if absorption were present (Eq. (1)), which yields a spectral index α =  −0.39 ± 0.01.