The line shape problem for the Balle–Flygare‐type microwave spectrometer is reexamined experimentally using the method of sine and cosine Fourier transforms with a phase correction. Two previous studies [E. J. Campbell, L. W. Buxton, T. J. Balle, M. R. Keenan, and W. H. Flygare, J. Chem. Phys.74, 829 (1981), and F. J. Lovas and R. D. Suenram, J. Chem. Phys.87, 2010 (1987)] are reviewed. Those results are combined with new experimental data to obtain a general description of line shapes obtained from this device. Our emphasis here will be on using specific examples to clarify the relationship between the frequency domain representations of experimentally measured time‐domain signals and the originating active species distributions.