A software defined radio (SDR) for communicating a plurality of radio signals over a wireless communications network. The radio comprising: a programmable system having a plurality of digital processors for processing digital data representing a digital form of the plurality of radio signals, the programmable system also for configuring operation of radio hardware for processing of the radio signals themselves; a configurable intermediate frequency (IF) interface for processing the plurality of radio signals for subsequent processing as the digital data communicated to the programmable system and the digital data received from the programmable system, the IF interface having a first connector for releasably connecting a modular IF filter component for use in the processing of said plurality of radio signals, the modular IF filter component being part of the radio hardware for selecting an IF center frequency and channel bandwidth of the SDR; and an RF platform coupled to the IF interface and configured for having with at least one radio portion, each radio portion for receiving and transmitting the radio signal over the communications network on behalf of the IF interface, said each radio portion having a second connector for releasably connecting a modular RF filter component for use in the processing of said plurality of radio signals, the modular RF filter component being part of the radio hardware for selecting an RF sub-band and RF center frequency of said each radio module; wherein the programmable system is adapted to configure operation of the SDR through recognition of the corresponding connected modular RF and IF filters.