Urban environment is an unexplored field of knowledge for military radio communication. There is an increasing need for understanding radio wave propagation, and how to model it, in urban terrain. The frequent lack of line-of-sight between a transmitter and a receiver means that the radio waves mostly have to propagate by diffraction over roof tops and around house corners. Radio waves will also be reflected and scattered by obstacles of different sizes and textures. FOI has acquired computer software called Radiowave Propagation Simulator (RPS), which was considered appropriately general and flexible. It is originally designed for coverage planning of cellular radio systems. This report describes how we studied the handling of the software and its usability for outdoor scenarios, which differ a lot from the original intended usage. We have compared simulated data to measurements made in Stockholm. We have found that it is complicated to design a correct enough model and to validate it by measurements. Still, the commercial software, that allows custom plug-ins, is considered a cost effective tool that can be recommended for future radio wave propagation calculations.