to answer ur questions it is a 4rth year university project so no sponsor. and yes i do mean data as apposed to voice. I did expect everyone to say the use voice for both the only reason I ask was that there can be issues in the rare event that a UAV loses connection with it operator in a voice system the UAV would be potentially rogue where as in a data style communication it would be possible to have smart UAVs able to follow the command of ATC until reconnected or the ATC has safely directed it potentially even making it land.