Radio networks are a large part of the business of the Communications Department of Thales UK. The integration, deployment, and configuration of these networks has become a more complex process as the networks have become larger - impacting both the technological development side and the physical network operation side. There is a knowledge gap, most keenly seen when bidding · on large new projects, as to what is possible and what technologies/sub-systems/configurations are best to use in any given system. This sits alongside an imperative to find a way to acquire or generate such knowledge at minimal cost, and certainly without the exorbitant costs of physically building deployment-scale test systems. This thesis addresses that knowledge gap methodologically, via computer simulation models. Simulation of a physical system can generate information that when analysed within the constraints of the model can give useful knowledge about the physical system being simulated. For this reason, a simulation software architecture was designed and implemented, enabling the simulation and modelling of a range of communication networks. This research was done in the Thales RCP (Radio Communications Products) Group, within the Communications Department, and as such its primary use was simulating High Frequency (HF) radios and their operational networks. Models were created of all layers involved in an HF radio system, following the outline of the architecture itself, which is based on the Open Systems Interconnection model. Using this simulation architecture, results gained about the behaviour of HF systems include comparative evaluation studies of HF radio protocols, as well as behaviour and performance profiling of novel protocols and of the configurations of existing systems. This thesis demonstrates that the information obtained from the simulation architecture can be used to address the primary motivating problem: reducing the knowledge gap that exists with these new, large radio network systems. The knowledge gap includes the effects of configuration, protocol, sub-system and so forth on the behaviour and performance of the network amongst other things. Thus, with this kind of knowledge now made available, decision makers are enabled to make more informed decisions at various stages in a project lifecycle, and hence the decision-making process is improved. Aside from internal Thales UK applications, the simulation architecture has been released as open-source. Although the models may be proprietary, the architecture provides an easy-to-use simulation tool, which is capable of quickly developing models for rapid prototyping of any layer in a HF radio communication network system.