A test station may include a test host, a signal generator, and a test chamber. Multiple devices under test (DUTs) may be placed in the test chamber during production testing. Radio-frequency signals may be conveyed from the signal generator to the multiple DUTs using a conducted arrangement through a radio-frequency signal splitter circuit or using a radiated arrangement through an antenna in the test chamber. The signal generator may broadcast initialization downlink signals. The multiple DUTs may synchronize with the initialing downlink signals. The signal generator may broadcast test downlink signals at a target output power level. The multiple DUTs may receive the test downlink signals and compute a corresponding downlink transmission performance level based on the received downlink signals. A given DUT is marked as a passing DUT if the downlink performance level is satisfactory. A given DUT may be retested if the downlink performance level fails design criteria.