Modelling of path loss behaviour in ultra wideband radio channels was revisited. Although simple but realistic standardized channel models have already been established, this paper attempts to provide detailed insights about the precision of the standardized model based on an extensive measurement campaign which covered whole areas inside an office room. Attention was paid to the frequency and distance dependency of path loss and their interrelation. It was found that the two dependencies can be modelled separately as the standardized UWB channel model assumed. Furthermore, this paper clarified the path loss modelling methodology to combat an ambiguous and non-unified model parameter derivation procedure. Finally, model parameters for path loss and shadow fading were derived based on the clarified method to complement the channel model parameter set.