This paper is concerned with the conception and the realization of a direct-sequence spread-spectrum digital mobile radio transmission at 910 MHz. The system has been used either as a spread-spectrum communication modem or as a wideband channel sounder. The performance measurements, carried out in the laboratory, reveal a good theory and experiment agreement and they clearly show various advantages of spread spectrum techniques. The radio propagation conducted measurements have shown the temporal and spatial behaviours of the urban mobile radio channel. The measurement results may be used for a statistical modeling of the channel which in turn could lead to the transmission quality improvement.