Compilation of observed f₃ values as a function of time since B-mode onset. Previously published f₃ measurements are shown by black stars (Arecibo, 327 MHz) and black crosses (LOFAR, 30−80 MHz). The 112 MHz measurements for the Tb and B modes from this work are shown with red circles and crosses. The f₃ value for 91 B-mode pulses right before a B-to-Q mode transition (session 221219) is plotted at an arbitrary time mark of 250 min. LOFAR Tb-mode f₃ measurements are shown with blue triangles. The points around t = 180 min show typical f₃ error bars for PRAO and LOFAR measurements from this work. Horizontal lines mark the range of validity of the exponential fit by Backus et al. (2011, dashed magenta line). The black line shows the power-law fit from Suleymanova & Pugachev (2017). The measurements for the Tb mode agree well with a power-law fit.