High-Tc superconducting thin films were prepared by DC sputtering. Contrary to diode sputter methods, in the triode configuration applied here no compositional adjustment of the ceramic YBa2Cu3Ox target appeared necessary. SrTiO3 (100) was the best substrate found so far. After an onset at Tco = 92 K, we found a complete superconductive transition at Tcf = 86 K. At the transition a five-order decrease in resistivity could be measured. On other substrates such as Al2O3, MgO and ZrO2 relatively poor results were obtained. Characterization was performed by SEM, x-ray diffraction and Rutherford backscattering (RBS).