Presented is a numerical study of the impact of the antenna pattern sampling resolution on the accuracy of Over-The-Air (OTA) throughput measurements. More specifically, a Line-Of-Sight (Random-LOS) testing scenario is addressed. The communication throughput is evaluated as the Probability of Detection (PoD) of a single bitstream based on the ideal digital threshold receiver model. The maximum deviation of throughput efficiency is computed as a function of the azimuthal sampling resolution for various generic antenna gain patterns. The coefficient of variation of the antenna gain pattern is introduced to evaluate the impact of the azimuthal sampling. The presented approach can be used to define the sampling resolution of the throughput performance of a device under test in Random-LOS OTA.