ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Tactical training ranges provide an opportunity for all of the armed forces to assess operational readiness. To perform this task the various training ranges have deployed numerous telemetry systems. The current design efforts in place to upgrade the capabilities and unify the ranges under one telemetry system do not address the training ranges' need to maintain their training capability with the legacy systems that have been deployed until the new systems are ready. Two systems that have recently undergone sustainment efforts are the Player and Event Tracking System (TAPETS) and the Large Area Tracking Range (LATR). TAPETS is a telemetry system operated by the U.S. Army Operational Test Command. The TAPETS system is comprised of the ground mobile station Standard Range Unit (SRU) and the aircraft Inertial Global Positioning System (GPS) Integration (IGI) Pod. Both systems require a transponder for the wireless communications link. LATR is an over the horizon telemetry system operated by the U.S. Navy at various test ranges to track ground based, ship based, and airborne participants in training exercises. The LATR system is comprised of Rotary Wing (RW), Fixed Wing (FW) Pods, Fixed Wing Internal (FWI), Ship, and Ground Participant Instrumentation Packages (PIPs) as well as Ground Interrogation Station (GIS) and relay stations. Like the TAPETS system, each of these packages and stations also require a transponder for the wireless communications link. Both telemetry systems have developed additional capabilities in order to better support and train the Armed Forces, which consequently requires more transponders. In addition, some areas were experiencing failures in their transponders that have been deployed for many years. The available spare components of some systems had been depleted and the sustainment requirements along with the increased demand for assets were beginning to impact the ability of the systems to successfully monitor the training ranges during exercises. The path to maintaining operational capability chosen for the TAPETS system was a mixed approach that consisted of identifying a depot level repair facility for their transponders and funding the development of new transponder printed circuit boards (PCB's) where obsolescence prevented a sufficient number of repairable units. In the case of LATR, the decision was made to create new transponders to take advantage of cost effective state-of-the-art RF design and manufacturing processes. The result of this effort is a new transponder that is operationally indistinguishable from the legacy transponder in all installation environments. The purpose of this paper is to present two successful system sustainment efforts with different approaches to serve as models for preserving the current level of training range capabilities until the next generation of telemetry systems are deployed. While the two programs illustrated here deal primarily with the transponder components of the systems, these same methods can be applied to the other aspects of legacy telemetry system sustainment efforts.