Like all DSC positioners, the antenna test positioners are built exclusively with brushless servo motors and optical encoders. Backlash below 0.005 degrees or 0.005 inches is standard. DSC’s proprietary motion control algorithms run on cots hardware that is sold in quantities of tens of thousands.
Years typically go by between breakdowns, but when service is needed, DSC systems are made for easy and rapid accessibility to every part. Whatever your antenna measurement requirements are, DSC probably has a solution.