Global H I profile of M 83 from our VLA observations (orange) and the results of feathering the VLA with the GBT observations (black). The systemic velocity appropriate for the centre of the galaxy is indicated with the vertical grey dashed line at 510 km s⁻¹ (see also Table 1). We also show H I observations of the same FoV of M 83 from LVHIS (Koribalski et al. 2018) and KAT7 (Heald et al. 2016) that we have sampled on the same spectral axis grid at their native angular resolution.