Modelling the effective antenna length. Panel a: effective antenna length as a function of λ_De using densities from RPW from solar wind analysis. The time of each observation in units of days since 2020-06-01 are colour-coded. The solid red curve shows a fit to the data (see text for details), and the dashed curve shows the extrapolation. Panel b: relative error of solar wind speed before (white) and after (red) correcting for L_eff.