An adjustable filter is responsive to a control signal to change a frequency response of the adjustable filter based on at least one of a geographic location, frequency spectrum information, and a status of a secondary internal radio. The control signal may shift a center of the pass band from a first center frequency to a second center frequency and/or change a pass band bandwidth from a first bandwidth to a second bandwidth. A transmitter includes an adjustable filter responsive to a control signal and controller configured to select a frequency response of the adjustable filter by generating the control signal based on a geographical location. In one aspect, the geographical location indicates a region of operation of the receiver and the frequency response is selected in accordance with the region.