The X Band Synthesized Converter (XBSC-TX) is used for testing satellites. In the downconverter section the desired satellite output after attenuation is downconverted to a 720 MHz IF for further processing and test of the satellite. The upconverter, if present, is likewise used to upconvert a 720 MHz test modulator output to the satellite output frequency to bypass the satellite during troubleshooting to ascertain performance problem location. The downconverter input frequency and upconverter output frequency are selected via thumbwheel switch on the front panel. Input and output connectors are located on the rear panel.