A Spread spectrum trainer comprising at least one transmitter and/ at least one receiver characterise by a plurality of interconnected modules adaptable for both comprising code generators; data generators and decoders; spreaders,frequency synthesizers; BPSK/FSK modulators; multipath simulators; noise source; costas loop ; delayed lock loop; and RF transmitter and RF receiver, together with means for altering the module connections and means for configuring the modules for varying the parameters thereof.