reflection waves and other like waves outside the reflector box 11 are intercepted by the reflector box 11 and lid 15 the coupling of undesired waves to the testing antenna 7a is reduced to a very low degree fig2 shows an example of the construction of a sector cell base station having three sector cells 9a 9b and 9c base station transmitter receivers 1 2 and 3 for transmitting and receiving radio waves to and from the three sector cells 9a 9b and 9c respectively and testing transmitter receivers 21 22 and 23 corresponding to the transmitter receivers 1 2 3 respectively are provided in an indoor installation 20 meanwhile the main antennae 6a 6b and 6c connected to the transmitter receivers 1 2 and 3 respectively are installed in an outdoor location the testing transmitter receivers 21 22 and 23 are connected to the testing antennae 7a 7b 7c respectively communications with sector cells 9a 9b and 9c are performed by radio waves radiated from the transmitter receivers 1 2 and 3 by way of the main antennae 6a 6b and 6c respectively here a system test for each of the sector cells is performed for example for sector cell 9a by transmitter receiver 1 and testing transmitter receiver 7a which transmit and receive a radio signal to and from each other by way of the main antenna 6a and testing antenna 7a respectively accordingly it.