Abstract: The diagnostic test uses the effects of closed loop power control in order to measure the return loss of a receive antenna in a CDMA radio system. A standard CDMA call is established under closed loop power control by a mobile in a test unit. Using a switch matrix, the call is directed on the incident path of a receiving antenna. After a stabilization interval, the mobile phone in the test unit is queried for its transmit power level. The established call is then directed on the reflected path of the receiving antenna. After a stabilization interval, the mobile phone is again queried for its transmit power level. The difference between the previous incident transmit power level and the new increased transmit power level is the return loss of the antenna.

Abstract: A system and method effectively combines communications of the base stations of multiple wireless systems on the same antenna structure. In one implementation, a wireless system combiner serves as an interface between base stations of first and second wireless systems (“first base station” and “second base station”) and a shared antenna to substantially eliminate spurious noise from the first base station at frequencies allocated to the second base station and prevent transmit power from the first base station from feeding into the reception circuitry of the second base station in a shared antenna configuration. The combiner includes a first combiner filter between a duplexer of the first base station and a common connection point and a second combiner filter between a duplexer of the second base station and the common connection point.