As is well known, in a 3G network scenario the quality of voice traffic over IP is greatly reduced due to the strong current limitations in terms of requirements regarding delay and guaranteed bandwidth. Moreover, perceived quality of VoIP communications depends on the individual telephone operator where the radio link is not always reliable for the entire duration of a conversation. In particular, the study concerns the effect of packet loss and the degree of improvement in the perceived quality which can be obtained by sending a duplicate copy of a voice packet through two different operators. In terms of perceived speech quality this approach leads to a significant improvement which stands between 0.5 and 1.5 MOS.