Comprehensive modelling of the ultra-wide band (UWB) radio channel necessitates a good knowledge of its fading statistics. To evaluate the fluctuations of the UWB channel, a propagation experiment has been conducted in the 3.1 - 11 GHz frequency band, involving different antenna locations and moving people. The presented results emphasize the difference between the spatial and temporal channel variability, and provide a practical assessment of the UWB signal fading distribution in the case of a dynamic environment.