A method of facilitating antenna calibration comprising: providing an apparatus comprising: a directional coupler having a first port , a second port , a third port and a fourth port , a power combiner/divider having a first port , a second port and a third port , and a magnitude and phase adjuster connected between the fourth port of the directional coupler and the third port of the power combiner/divider; and configuring the apparatus to: receive (S1210), at the first port of the directional coupler, a calibration signal from a radio transmitter, such that the calibration signal results in a coupled calibration signal at the third port of the directional coupler via coupling; receive (S1220), at the second port of the directional coupler, an interference signal from an antenna, such that the interference signal results in an isolated interference signal at the third port of the directional coupler via isolation and a coupled interference signal at the fourth port of the directional coupler via coupling; modify (S1230) a magnitude and a phase of the coupled interference signal to generate a modified interference signal; and combine (S1240) the coupled calibration signal, the isolated interference signal and the modified interference signal into an input to a measurement receiver, wherein the modified interference signal and the isolated interference signal cancel each other. providing an apparatus comprising: a directional coupler having a first port , a second port , a third port and a fourth port , a power combiner/divider having a first port , a second port and a third port , and a magnitude and phase adjuster connected between the fourth port of the directional coupler and the third port of the power combiner/divider; and configuring the apparatus to: receive (S1210), at the first port of the directional coupler, a calibration signal from a radio transmitter, such that the calibration signal results in a coupled calibration signal at the third port of the directional coupler via coupling; receive (S1220), at the second port of the directional coupler, an interference signal from an antenna, such that the interference signal results in an isolated interference signal at the third port of the directional coupler via isolation and a coupled interference signal at the fourth port of the directional coupler via coupling; modify (S1230) a magnitude and a phase of the coupled interference signal to generate a modified interference signal; and combine (S1240) the coupled calibration signal, the isolated interference signal and the modified interference signal into an input to a measurement receiver, wherein the modified interference signal and the isolated interference signal cancel each other. receive (S1210), at the first port of the directional coupler, a calibration signal from a radio transmitter, such that the calibration signal results in a coupled calibration signal at the third port of the directional coupler via coupling; receive (S1220), at the second port of the directional coupler, an interference signal from an antenna, such that the interference signal results in an isolated interference signal at the third port of the directional coupler via isolation and a coupled interference signal at the fourth port of the directional coupler via coupling; modify (S1230) a magnitude and a phase of the coupled interference signal to generate a modified interference signal; and combine (S1240) the coupled calibration signal, the isolated interference signal and the modified interference signal into an input to a measurement receiver, wherein the modified interference signal and the isolated interference signal cancel each other. <EOS>