From agriculture to industry, from the office to our homes, Wireless Sensor Networks (WSNs) are becoming a part of everyday life in many application areas. In typical WSN applications, the sensor nodes are fixed and interconnected amongst each other and to the outside world on a permanent basis. However, in certain types of applications, where the area to sense is wide and sensors are sparsely distributed, a different approach can be used. A mobile node can roam in the sensor field to collect and exchange information with disconnected clusters of nodes. This paper addresses the limitations of real world sensor networks with such moving nodes. To understand the behavior of a typical WSN node in these situations, two types of experiments were conducted. To begin with, the communication performance was measured, in a static scenario, establishing the base-line behavior. Afterwards, a second set of experiments was carried out with fast moving nodes at different speeds. Finally, the results of the two experiments were compared and analyzed. Keywords-Connectivity, Coverage, IEEE 802.15.4, MICAz, Mobility, Wireless Sensor Networks.