The VIAVI UC-584 Series Transponder Antenna Couplers are designed to solve the problem of reliable FAR Part 43 Appendix 'F' ERP (Effective Radiated Power) and transponder MTL (Minimum Trigger Level) testing, in the high multi-path ramp and hangar environments. The innovative design of these couplers include an integral positioning slot ensuring a high level of measurement repeatability is achieved, saving test time.