Using ad hoc networks as alternative means of communication in disaster situations is a salutary solution. However, analysing application performance is mandatory for evaluating such a possibility. In this paper we present the two aspects of our approach to application performance assessment on wireless ad hoc networks. The first aspect refers to real-world tests in which we quantify objectively the relationship between network conditions and application performance. The second aspect is represented by the wireless network (WLAN) emulator that we design to run on StarBED, the large-scale network experiment environment of the Hokuriku Research Centre in Ishikawa, Japan. By combining these two aspects we perform experiments with real applications, while having full control of the network conditions in which the application is tested (when using emulation).