A Transportable Measurement Facility (TMF) incorporating antenna, r-f, and reply processing elements of a Discrete Address Beacon System (DABS) sensor has been sited at, and in the vicinity of, several FAA terminal ASR's throughout the United States. Data collected at these sites have been thoroughly analyzed to verify the design of the DABS sensor and to establish the need for design refinements. This report presents the results that pertain to DABS and ATCRBS Mode range and azimuth accuracy and to the total ATCRBS Mode reply processing performance, It is shown that both range and azimuth accuracies for the DABS sensor are a factor of four to five better than those provided by existing ARTS (BI-4) interrogators, and that the average blip/scan ratio is 98% or better, dropping only a few percentage points in crossing track situations.