The absolute total isotropic sensitivity is determined for a communication device receiver circuit that is within a scattered field chamber (SFC) and is receiving communications from a base station simulator. Movement of a mode stirrer device within the SFC is controlled to sequentially move the mode stirrer device to a plurality of different static positions. The different static positions of the mode stirrer device are configured to differently mix polarizations of incident RF fields in the SFC. At each of a plurality of the different static positions of the mode stirrer device, the transmission power level from the base station simulator is varied through a plurality of different transmission power levels. At each of a plurality of the transmission power levels, a bit error rate and a received signal strength at which the communication device receives the communications from the base station simulator are measured. The absolute total isotropic sensitivity of the communication device receiver circuit is determined in response to the measured bit error rate, the measured received signal strength, and the associated transmission power levels.