Extended Data Figure 6: Raw and processed spectra.
From: An absorption profile centred at 78 megahertz in the sky-averaged spectrum
a, Typical raw 13-s spectra from H2 for each of the receiver’s ‘three position’ switch states. The small spikes on the right of the antenna spectrum are FM radio stations. b, The spectrum has been partially calibrated (‘Three position’) using the three raw spectra to correct gain and offset contributions in the receiver and cables, then fully calibrated (Calib.) by applying the calibration parameter solutions from the laboratory to yield the sky temperature. c, Residuals to a fit of the fully calibrated spectrum with the five-term polynomial foreground model (equation (2)). In b and c, the frequencies listed in the legend give the binning used for each curve.
