A portable radio communication system for enabling duplex communication on portable radios is provided. The portable radio communication system comprises a host radio having a host radio antenna and an accessory having an accessory antenna. The host radio antenna is operated to receive signals simultaneously on at least two channels during a dual watch mode of operation or receive signals on a single channel during a single watch mode of operation. The portable radio communication system further comprises at least one switch coupled to the host radio antenna and the accessory antenna. The switch enables duplex communication during the dual watch mode of operation or single watch mode of operation by routing transmit signals from the host radio to the accessory antenna for transmission while the host radio antenna receives signals during the dual watch mode of operation or single watch mode of operation.