The present invention relates to a device and method for simulating a radio channel with a defined characteristic between at least one antenna port (102a, 102b) of a first device (101), and a second device (103) in a test environment. The device comprises a first antenna (104a) adapted to receive signals, and arranged to provide a first radio channel (105a) between the first antenna (104a) and the second device (103) and, a second antenna (104b) adapted to receive signals, and arranged to provide a second radio channel (105b) between the second antenna (104b) and the second device (103). A characteristic of the second radio channel (105b) is dissimilar to a characteristic of the first radio channel (105a). The device further comprises a modifying circuit (107a, 107b) adapted to modify an amplitude relation between the received signals, and a multiport circuit (106) arranged to connect the first and second antennas (104a, 104b) with the at least one antenna port (102a, 102b). The multiport circuit (106) is also adapted to combine the modified signals, and to forward the combined signals to the at least one antenna port (102a, 102b), thereby simulating a radio channel between the at least one antenna port (102a, 102b) and the second device (103) with a characteristic which is a combination of the characteristic of the second radio channel (105b) and the characteristic of the first radio channel (105a) in a relation corresponding to the modified amplitude relation.