Upper limits of the total radio flux density for a jet with the properties of π¹ UMa theoretically derived from Eq. (7) with an opening angle of around 40°, showing a positive slope of α_op = 0.6 for the optically thick wind and a decrease at the turnover frequency for the optically thin part using the quantities for model A (see Table 5). The observational upper limit radio flux density of π¹ UMa for Ku-band is shown as a black arrow. The C-band upper limit flux density would lie beyond the plotting range at 23 μJy.