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架空明线12路载波的线路传输频率最高为143kHz,小同轴电缆300路最高为1364kHz,960路最高为4MHz,3600路最高可达18MHz,与极长波、长波导航、中波和短波调幅无线广播的频段重合。导航和无线广播的信号极强(辐射功率几千瓦、几百千瓦或几千千瓦),在自由空间传播,既可能经由通信线路进入载波系统,也可能直接被载波通信设备所接收。由于载波通信系统接收端的信号输入电平很低(一般为—50dBm左右),很容易受到无线电干扰。
Overhead Line 12-way carrier line transmission frequency of up to 143kHz, 300 small coaxial cable up to 1364kHz, 960 up to 4MHz, 3600 up to 18MHz, and very long wave, long wave navigation, short wave and medium wave AM radio Coincide with the frequency band. Navigation and radio signals are extremely strong (radiated power of a few kilowatts, hundreds of kilowatts or thousands of kilowatts), spread in free space, either via a communication line into the carrier system, it may be directly received by the carrier communication equipment. Because the signal input level of the receiving end of the carrier communication system is very low (generally about -50 dBm), it is susceptible to radio interference.