The invention is a compact three-port signal combiner suitable for use in a base station having two different wireless systems. The combiner is designed as a four-port network, but one of the ports is terminated with a predetermined load, thus leaving three ports for connection to user equipment. A first port (A) receives from an antenna a first input signal comprising first and second receive bands and transmits to the antenna a first output signal comprising a transmit band. A second port (R), connected to the first wireless system, outputs to the first wireless system a second output signal comprising the first and second receive bands. A third port (T\R) outputs, to the second wireless system, a third output signal comprising the first and second receive bands and receives from the second wireless system a second input signal that is to be transmitted from the first port.