Abstract: A wireless transmitter for generating and transmitting wireless signals comprises a main unit and a plurality of auxiliary units, each having an outer casing and a fastening mechanism for connecting the casing of each auxiliary unit to that of the main unit. The main unit includes a signal generator for generating a plurality of carrier signals simultaneously and an interface for transmitting a carrier signal to each of the auxiliary units when connected thereto. Each auxiliary unit comprises a power amplifier and an optional upconverter, and a connector for connecting an antenna thereto. The signal generator of the main unit is configurable to generate different predetermined waveforms which are received through a communication interface. The transmitter unit is portable and a coupling mechanism is provided to lock the transmitter onto a backpack support.