Assume that the spectrum available is 145 to 148 mhz , the transmitter frequency in a repeater is either 600 khz above or 600 khz below the receiver frequency , and there are 54 different pl tones available .

假设频谱为145至148mhz，中继站的发射信号应当比接收到的信号增加或减少600khz，有54个不同的亚音频音调可以使用。