Along with the proliferation of wireless communication with diverse services and applications, effective spectrum usage remains a challenge. Cognitive radio networks (CRNs) stand as a solution for the increasing demand on naturally limited frequency spectrum. As opposed to broad research work on modeling and simulation of these networks, implementation studies are more confined due to the practical limitations of traditional radio devices. In this paper, the CRN test bed we implemented using software defined radio peripherals is introduced, and the performance of this testbed is evaluated with varying network parameters like primary user (PU) traffic intensity and the noise level in the environment. The real time spectrum sensing performance are given by means of miss detection, false alarm and detection rates along with system utilization. Testbed implemented provides promising results as well as being basis for our future work covering multi-hop, multi-channel CRNs.