Several efforts are currently underway to enhance electronic warfare (EW) training on Air Force aircraft using onboard, 'rangeless' EW training. On- board EW training provides closed-loop simulations of air-defense environments for realistic in-flight combat training of aircrews. The training capability can be an integral part of the aircraft operational flight program (OFP) or can be an external simulator carried onto the aircraft. An emerging requirement for embedded EW training is in support of live, virtual, constructive (LVC) threat simulations in multi-element training exercises like Red Flag. The LVC experience requires coordination of multiple air and ground threat systems with multiple aircraft 'players' where some are simulated and some are real. This concept allows training against denser, more realistic threat arrays than are typically available on most live-fly EW ranges. This paper provides highlights of an investigation conducted to support a low-cost EW training system that meets current and future requirements of a ground-based threat simulation tool that can stimulate the aircraft EW subsystems and monitor aircraft and operator responses over existing aircraft data links. The investigation identified system architectures for an off-board training system that required minimum changes to the aircraft OFP while providing a centralized threat simulation for multiple aircraft in training exercises without the need for expensive training ranges or flight equipment. A primary feature of this concept is a ground-based threat simulator based on the Air Force Research Laboratory's Experimental Common Immersive Theater Environment simulation environment and the Georgia Tech Research Institute on-board embedded training system the Virtual Electronic Combat Training System.