This technical report documents the design, development, and performance of a Precision Antenna Measurement System PAMS which is used to perform dynamic measurements and evaluate the radiation characteristics of airborne antennas. The PAMS operates over the frequency range of 100 MHz through 18 GHz and can be used to measure the cross section of aircraft and chaff. The system is slaved to either an ANMSQ-1A or ANFPS-16 track radar for aircraft acquisition. The report details the design parameters and covers the data acquisition and computer programs used in the data reduction. The system performance is presented and actual antenna patterns given for various antenna configurations on a C-131 aircraft.