为什么对讲机可以实现十多公里的通讯距离，但手机必须依赖基站？
首先，我们需要明确的是，手机和对讲机的功能是不一样的，换句话就是，我们在设计这两种产品之前，对他们的市场定位是不同的，因此也就造就了其不同的设计。
其实主要就两个方面：一是频率，二是容量。
如果不考虑这两点，手机基站达到这个范围完全没问题，甚至二倍也没问题。
电磁波频率越高衰减越快，现在234g频率越来越高，以中国移动为例，当前的4g基站已经最高达到了2635MHz，而对讲机一般100到400兆赫兹不等，天生相同功率下传的更远。
对讲机多为点对点半双工语音通讯，其发射功率一般在2W及以下，有150MHz、450MHz两个频段，有16或20个信道供选择，号称户外开阔地带最大通讯距离5~10km，其实很难达到。这种点对点半双工语音对讲通讯，相对于手机本身和移动通信网络来说，简直是简单的不能再简单了，用途也不一样，因此它不需要任何基站。
为什么对讲机跟手机不一样？一个是远距离长波传输，一个是短波短距离。物理上的本质来说，4g.5g.6g.7g，这些G代表的是频率。长波丶短波说的是频率问题，为什么叫长波?传输的距离远，为什么长波传输的距离远？因为它的波峰波谷距离比较长，波峰波谷之间就高达几百米，这是长波天生的性能，所以长波只要几个波长就可以达到十公里之外，这就是当年的2G大哥大基站的时候，一个基站覆盖十几公里。
对讲机用的频率是低频，波长比较长（绕过障碍物的能力强），所以可以以较小的功率获得较长的传播距离。而手机用的是高频，波长很短，传播距离也有限（绕过障碍物和抗干扰能力），所以必须靠基站来覆盖，然后基站靠有线传输。
至于手机为什么选高频？那是因为低频频段都被占领了啊（想想小时侯电视的两根大辫子），运营商也想要低频呀，可以少建很多基站的。
不过实际上，对讲机也可以通话距离更远，只需架设中继台，是不是也和基站比较象啊。
手机为什么要接入基站，这个可怎么说哪？当初开发手机是通信制造业开发的，研发设备的都是通信制造商，他们的主要卖的产品就是基站，手机其实是为了让基站有用的副产品，想当初手机都是从属于基站的电子产品。如果硬要问为什么手机需要基站的话，只能说：如果不是为了卖基站就不研发手机了，哈哈。要知道，实际上是先有的"蜂窝通信"的基站，后来才发明的手机。
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