The NEC LD7215, LD7215C and LD7215D are PPM-focused traveling wave tubes designed for use as the final amplifiers in the earth-to-satellite communications transmitter. These are capable of delivering an output of 3 kW over the range of 5.85 to 6.425 GHz. They provide a high power gain of 46 dB at an output power of 3 kW, and flat gain variation of 2.5 dB by LD7215, 1.0 dB by LD7215C and LD7215D at small signal level in the full frequency range. Furthermore, they are of rugged and reliable design offering long-life service. Both LD7215 and LD7215D are fully compatible with TH3640.