  The effects of planar hole content, p, on the static magnetic susceptibility,
chi(T), of Y1-xCaxBa2Cu3O7-delta polycrystalline samples were investigated over
a wide range of Ca (x) and oxygen contents. Non-magnetic Ca2+, in the 3p6
state, induces a Curie-like contribution to chi(T) that increases
systematically and non-linearly with x but is almost independent of p. We argue
that this arises from statistical clusters containing two or more nearest
neighbor Ca atoms. We have again found that the pseudogap in the quasi-particle
spectral weight appears abruptly below a planar hole content p = 0.190 +/-
0.005.
