In this work we report c-axis conductance measurements done on a superlatti
ce based on a stack of two layers of YBa2CU3O7-delta and Seven layers of Pr
Ba2Cu3O7-delta (2.:7). We find that these quasi-two-dimensional structures
show no clear superconducting coupling along the c axis. Instead, we observ
e tunneling with a gap of Delta(c) = 5.0 +/- 0.5 meV for the direction perp
endicular to the superconducting planes. The conductance spectrum show well
defined quasiperiodic structures which are attributed to the superlattice
structure. From this data we deduce a low-temperature c-axis coherence leng
th of xi(c) = 0.24 +/- 0.03 nm.