The correlation matrix of the power spectrum multipoles of the faint model. The signal is strongly correlated at |$\ell = 0$| (the monopole) on small scales |$k\gtrsim 0.2 \, {\rm Mpc^{-1}}$|⁠. The correlation becomes weaker at higher |$\ell$|⁠. The non-uniform sampling of k-space due to the baseline distribution is propagated into the covariance calculation.