Sunyaev-Zel'dovich cluster surveys using a large beam

Sunyaev Zel'dovich cluster surveys can be used to constrain cosmological parameters. Extracting clusters from the primary anisotropies and the unresolved background from very faint clusters is simple when the telescope beam size is small (1 arcmin), but could be difficult if the beam is larger (8 arcmin). By reference to examples, we show that this is possible by carefully designing the depth of the survey.