Solid lines show 1σ sensitivity per channel (15.626 MHz, or ~18 kms^-1 resolution) for the five ALMA-FF fields. The sensitivity is relatively homogeneous as a function of frequency, with variations up to ~30% due largely to the transmission of the atmosphere, as the same shape is observed in all five clusters. The atmospheric transmission at these frequencies is fairly flat, with no strong features present in any of the SPWs. Higher 1σ level values are observed near the edges of some SPWs (MACSJ 1149 in particular), due to the loss of sensitivity at the edges and/or the combination of executions after transforming to the barycenter frequency reference.