The leading HF has two functions: receiving the satellite program signals of Zhongxing 9 and Zhongxing 9A, and receiving the positioning signals of Beidou system. Based on the functions of down-conversion and signal amplification, the satellite program signal and Beidou positioning signal are combined by a combiner (* * * cable transmission technology) and transmitted to the satellite receiving decoder by a 75 Ω coaxial cable. Crystal oscillator and Beidou antenna oscillator are added to the main control, which has higher gain and better signal.