Normalized χ²/N_DOF of VELOCE Fourier series fits vs. the median uncertainty of the RV measurements for 151 non-SB1 Cepheids. The rapid increase of χ²/N_DOF for precise measurements with typical uncertainties better than 20–40 m s⁻¹ shows the existence of additional signals that are not reproduced by Fourier series models with constant P_puls. The three longest-period Cepheids in the sample, GS Lup, SV Vul, and S Vul are labeled and highlighted.