4H-SiC RF Bipolar Junction Transistors (BJTs) have been designed and tested at 425 MHz for the first time. The epitaxial emitter structure with collector and base thickness of 5 pm and 0.1 mum, respectively, shows a maximum current gain of 15 and a common emitter breakdown voltage of 500 V. The f(T) of this device was about 1.5 GHz. The epitaxial emitter device, with an emitter width of 2.5 mum and an emitter periphery of 2.62 cm, has demonstrated an output power of 50 W/cell using 80 V power supply in common emitter, Class AB mode. The pulse width was 100 mus and duty cycle was 10%. The collector efficiency at the power output of 50 W was 51% with a power gain of 9.3 dB. The peak large signal power gain was 9.6 dB.