Comparison of results according to the method proposed in Paper I (using apodization, beam correction, and noise subtraction) obtained from fits with different upper limits 0.01 <k_m < 0.06 arcmin^-1 in spatial frequency. Error bars are given in two cases to provide an impression of formal uncertainties of the least square fits. The horizontal black dotted line indicates the Kolmogorov spectral index γ = −8 / 3, the solid vertical lines bracket the velocity range with average brightness temperatures T_{B aver} > 0.5 K.