Long Josephson junctions have for some time been considered as a source of THz radiation. We consider here a stack of Josephson junctions as a model for the anisotropic high temperature superconductors in particular those of the BSCCO family. Solitons (fluxons) moving coherently in such junctions is a possible source for radiation. Analytical computations of the bunched state as well as bunching inducing methods are discussed. A new model for the interpretation of THz radiation experiments is suggested.