Today, Wireless Sensor Networks (WSNs) with open source operating systems still need many efforts to guarantee that the protocol stack succeeds in delivering its expected performance. This is due to subtle implementation problems and unexpected interactions between protocol layers. The subtleties are often related to the judicious choice of parameters, in particular those related to timing issues. As these issues are often not visible in simulation studies, this paper proposes a low-cost versatile measurement testbed and demonstrates its usefulness in measuring the performance of RDC protocols. We demonstrate how the testbed helped to identify bugs in the implementation of an RDC protocol.