4 GHz frequency coverage with the two backend units, XFFTS-1, and -2. The spectra have been extracted and averaged within the beam towards the brightest ATLASGAL source in the science demonstration field, AGAL340.054−00.244 (Urquhart et al. 2014a, see also Fig. 8). Red labels mark the brightest spectral lines expected in the observed spectral coverage. The spectrum recorded by XFFTS-2 has been offset for clarity.