Abstract: In operations such as seismic exploration seismic waves are generated at a shot point. The amplitudes of successive samples of seismic waves appearing at a plurality of detector stations variously spaced from said shot point in the wake of generation thereof are converted to digital codes. The codes from all the detectors are transmitted in sequence and on a real time basis by spread spectrum radio pulses to a master station.A plurality of data acquisition units each including a radio transponder and a seismic detector are located at each of a plurality of spaced seismic detector stations in a seismic prospect. A master radio station means is located in or adjacent to the prospect.