Time vs. frequency diagrams for the BRITE red-filter photometry of 28 Cyg in 2014. The bottom panel shows a single time bin, the middle panel shows 2015, and the top panel represents 2016. The discrete Fourier transform frequency spectra werecalculated in 40-day intervals with a step of 1 d. The common amplitude scale appears on the right. Horizontal lines occur where data from different set-ups were stitched together. It should be noted that the diffuse appearance of f_Δ32 (0.05 c/d) and f₁ (1.38 c/d, the Štefl frequency) and the cyclic anti-phased variability of the two g modes f₂ (1.54 c/d) and f₃ (1.60 c/d).