  Scanning tunneling spectroscopy was performed on c-axis
Y{1-x}Ca{x}Ba2Cu3O{7-delta} thin films for x= 0, 0.05, 0.15 and 0.20 at 4.2K.
The measured spectra show main-gap, sub-gap and satellite features which scale
similarly in energy versus Ca-doping, suggesting that they are associated with
a single pairing energy. The data is analyzed with a multiband tunneling model
which attributes the sub-gap features to the chain band and the satellite and
main-gap features to the plane band for d+s pairing symmetry. These results
suggest that the superconductivity in Y{1-x}Ca{x}Ba2Cu3O{7-delta} involves
multiple bands.
