Chevalier diagram of SN 2019oys (blue star marker for ∆t = 201 days and an orange star marker for ∆t = 221 days) with other Type Ib (grey circles) and IIn (grey squares) SNe. Also plotted for reference (green diamonds) are the two peaks observed in the 15.7 GHz light curve of SN 2014C (Anderson et al. 2017) which showed similar behaviour to SN 2019oys in the optical. The diagram shows the peak spectral radio luminosity, $L_{v_a}$, against its frequency, v_a, and the time of the peak, ta. Lines of equal shock velocity (black) and mass-loss rates (red; assuming wind velocity of 100 km s⁻¹ ) are plotted. We assumed equipartition here (ϵ_e = ϵ_B = 0.1, f = 0.5), and p = 3 for the plotted lines. However, we note that we find p > 3 from the spectral slope of the optically thin regime of SN 2019oys. Our assumption of p = 3 is here to make the comparison between other CCSNe and SN 2019oys more straightforward as p ≃ 3 is usually observed for CCSNe.