Low SWaP (Size, Weight, and Power) clocks will play a key role in new alternative positioning, navigation, and timing (PNT) systems designed to reduce or eliminate dependence on the Global Positioning System (GPS). Such systems are of interest for operation onboard small satellites, aircraft, or ground systems. The limited performance inherent in low-SWaP clocks can be mitigated by ensembling several independent devices; then steering an output signal to realize the implicit ensemble mean. Adding the capability to detect and isolate errors in a single clock would complete the implementation of a compact onboard timing system to support future resilient PNT capabilities. The objective of the CONTACT project is to create and operate a testbed to support the study and development of such timing systems. This paper describes the current design and implementation of the testbed on a Software Defined Radio (SDR) hardware platform and presents test results for an ensemble of three Chip Scale Atomic Clocks (CSACs).