Distribution of PT frequencies vs. S/N contribution in the EPTA20 dataset for three different CGW source positions and pulsars at 1 kpc (dark blue squares) and 4 kpc (light blue dots). The CGW frequency (ET frequency) is indicated as the vertical dark blue line. The fundamental frequencies of the PTA with T_obs = 10 yr are indicated with the vertical grey lines and labels. Top: Virgo cluster. Middle: P₁ = (RA 18 h, Dec −22.5 deg). Bottom: P₂ = (RA 3 h, Dec −45 deg). Due to the dependence of the strain on the angular distance between the pulsar and the source (cf. Eq. (5)), the S/N varies across the three positions.