Recent observations have shown the presence of non-thermal emission of synchrotron nature in protostellar jets, which was formerly associated only to relativistic jets. On the other hand, it has been observed that some protostellar jets show a precession effect in their movement. In this work we have carried out 3D MHD simulations of a precessing protostellar jet, including a time-dependent ejection velocity. From these numerical results, synthetic radio emission maps were performed in order to do a polarization study of the synchrotron emission. The goal is compare these results with observations of the HH 80 object.