The Model 35ST1G18 is a self contained, forced air cooled, broadband hybrid solid state and traveling wave tube (TWT) microwave amplifier designed for applications where low harmonic content is required in sub-band ranges and where high gain and moderate power output are required. A reliable amplifier system provides a conservative 35 watts minimum at the amplifier output connector with low harmonics. Stated power specifications are at the fundamental frequency. The amplifier's front panel digital display shows forward and reflected output plus extensive system status information accessed through a series of menus via soft keys. Status indicators include power on, warm-up, standby, operate, faults, excess reflected power warning and remote. Standard features include a built-in IEEE- 488 (GPIB) interface, 0dBm input, gain control, RF output sample port, VSWR protection for the TWT only, plus monitoring of TWT helix current, cathode voltage, collector voltage, heater current, heater voltage, baseplate temperature and cabinet temperature. The appropriate sub-band is user selected from either the front panel menu or the GPIB interface. Modular design of the power supplies and RF components allow for easy access and repair. Use of switching mode power supplies results in significant weight reduction. Housed in a stylish contemporary cabinet this unit is designed for bench top use but can be removed from the cabinet for rack mounting. The Model 35ST1G18 provides readily available RF power for a variety of applications in Test and Measurement, (including EMC RF susceptibility testing), Industrial and University Research and Development, and Service applications.