The characteristics of the free gas jet, during its interaction with an upstream moving shock, were investigated experimentally. The initial strength of the shock remained constant and equal to M, = 1.34 whereas the Mach number of the free gas jet M, varied in a wide range of sub- and transonic values from M, = O up to M, = 1.4. It is shown that in the presence of the moving shock the jet characteristic becomes strongly modified. Outside the jet originates a cluster of pressure waves which moves upstream in jet surrounding. Spatial and frequency characteristics, as well as the number of pressure waves in the cluster, depend on the shock amplitude and the exit velocity of the free gas jet.