A system and method for converting carrier frequencies of a wireless communication system is provided. The system and method allow expansion of coverage areas of wireless communication systems, such as a mobile/cellular telephone system. In one embodiment, the system converts RF signals in the PCS band to ISM band, and transmits the ISM signals to a distant repeater station. The repeater station receives the ISM signals and down converts the ISM signals to the PCS band. The PCS signals are retransmitted in a new cell thereby creating a new coverage area. Radio frequency signals are down converted to an Intermediate frequency for channel selectivity and narrow band filtering. Channel selectivity circuitry allows quick reuse of other channels in the same cell. The channel selectivity circuitry includes a SAW filter which significantly reduces out of band interference. The system includes a microcontroller to permit use of programmable synthesized sources for the local oscillators thereby facilitating a variety of communication bands to be utilized in the system.