International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / Over the last year, the Telemetry Data Center at White Sands Missile Range has conducted extensive comparative testing between its’ 20 year old Best Source Selector and several “off the shelf” selectors currently available. This paper explores the concerns involved in the process of selecting a new Best Source Selector and examines the inherent problems and differences associated with the old and new selectors.