首先就是工作频率上的区别啊。这两个频段上都有一些区间是国家划分给公众和单位,企业使用的频率范围。所以对讲机的工作频段也就多集中在了400-470MHz和136-174MHz。通话距离上150MHz和400MHz的对讲机在城区里的话400MHz的对讲机通话距离要远一点，因为天线增益较150MHz的机器高。在山区的话150MHz的对讲机通话距离较远，因为有电波绕射的存在性。功能上讲的话两种对讲机都差不多的。
发射机输出功率越强，发射信号的覆盖范围越大，通信距离也越远。但发射功率也不能过大，发射功率过大，不仅耗电，影响功放元件寿命，而且干扰性强，影响他人的通话效果，还会产生辐射污染。各国的无线电管理机构对通信设备的发射功率都有明确规定。
什么是高频对讲机？
高频的对讲机是一种工作在短波频率高端的对讲机，一般指频率为400-470的对讲机。
在日常对讲机的使用中，根据中国无线电管理委员会规定，对讲机频率一般做如下划分：
1、专业对讲机：V段136-174MHZ，U段400-470MHZ;
2、武警公安用：350MHZ;
3、海岸用：220MHZ;
4、业余用：433MHZ;
5、集群用：800MHZ;
6、手机：900/1800MHZ;
7、公众对讲机：409-410MHZ。
对讲机直呼台调高频还是低频好？
直呼台是不是就是不要中继对讲机直接通话的意思？
如果是在城里使用，高频信号穿透力强，所以一般选择高频段通话；
如果是在旷野使用，低频信号绕行能力强，一般选择低频段通话。
民用对讲机最大距离是多少？
民用对讲机功率0.5-1W，通常通讯距离为1公里左右。但是这个也有很大出入。通讯距离与两者之间的环境条件，电磁干扰情况等有很大关系。例如，一台在高山上，一台在平地上，中间视线无任何障碍物，通讯距离要5公里以上。如果在偏僻的草原通讯距离也可以很远，如果在城市里，由于障碍物多，电磁干扰严重，通讯距离就很近了。
普通民用，国产的就行，保安，消防，门卫什么的，输出功率5瓦足够，开阔地3公里。频点需要到无委会申报申请，批下来再去买相应频点的电台。如需要远距离通话，就需要建中继站，大概能覆盖直径30公里左右（平原，无高山阻挡。）
无线电对讲机中继台?
对讲机中继台是用来增大对讲机通讯距离的设备，当两台对讲机的距离超过了对讲机信号辐射范围时，对讲机将收不到有效信号，这时，就得用对讲机中继台。中继台的作用就是将收到的信号转发出去，完成信号之间的中继。
对讲机中继台，又称中转台、转发台、差转台、IP中转台，是无线通讯系统不可缺少的重要设备。是在无线对讲系统中，用于增大通讯距离，扩展覆盖范围的设备，比如可以扩大车载台、手持对讲机的呼叫范围和通讯能力，大幅度提高您的工作效率。
目前最常见热门中继台型号:
摩托罗拉GR300
摩托罗拉GR3188
摩托罗拉GR3688
摩托罗拉CDR700
目前常见的品牌有：
摩托罗拉(MOTOROLA)中继台/中转台
健伍（KENWOOD)中继台/中转台
威泰克斯(VERTEX STANDARD)中继台/中转台
海能达（Hytera）中继台/中转台。
外接天线及馈线就可组成完整的中继系统。
买了对讲机，怎样才能在中继台上谈笑风生？
对于新HAM来说，第一种让我们觉得非常神奇的设备可能是中继台——好像全地区所有的火腿都在上面聊天！而只有等到了第一次和其他的HAM出去架设短波电台、或者是经常参加中继活动之后，中继台的光环才会慢慢褪去，回归到日常使用的工具作用中去。中继台里面到底有什么？
一台自制的中继台，你能看到里面塞了两台车台
首先我们可以从它的表现中来看出一些端倪：中继台可以让很多原本不能通联的电台互相“通联”，出现在同一个频率上。这也是为什么其得名“中继台”的原因。一个架设位置良好的中继台能够听到上行频率上位于远处的信号，并将其再次发射在另一个频率（下行频率）上，使得所有守听着下行频率的朋友们都能够抄收到这个信号，而想要回复的朋友，则同样在上传频率上发射，这样通过中继台的转发，两个原本不能够互相通信的电台就能够完成一次通信了。
使用中继台一般来说非常容易，你所要做的只是确认当地的无线电中继的频率和参数，然后写入你的对讲机即可。我们刚刚拿到对讲机，开始自己的第一次通联的时候，我们只需要和朋友约定好一个频率即可。但如果你在使用对讲机的时候，还要输入频差和亚音。这些设定一般以这样的形式出现“439.750-588.5”，这个数据又是什么意思呢？
我们都知道在使用对讲机的时候两个人不能同时说话，电波在空中“打架”，谁的信号都听不清。使用中继台的时候也是一样，之不过对于中继台来说是“左腿绊右腿”式的干扰，大部分的中继台都会采用不同的频率以避免自己的发射对于自己的接收信号的干扰。而两个频率之差一般来说是固定的。对于430MHz段的话，一般来说频差是5MHz。而144MHz的话频差一般为0.6MHz。一台下行频率（即平常的守听频率）为439.750的中继台，其上行频率一般为434.750MHz。
调整频差的选项
而亚音（88.5Hz）则是为了避免干扰，试想如果中继台对于上行频率上的信号无条件的转发，那么在下行频率上势必就会收到大量的无用信号。于是我们对中继台进行设定，使得其只转发信号中包含亚音频的无线电信号，我们在设定对讲机的时候也同时要设定亚音频。这样在使用中继台的时候，中继台就只转发那些包含亚音频，确定是要使用中继台的信号，而对其他的信号置之不理。很多朋友刚刚拿到对讲机，被老火腿提醒“你没上去中继！”，很多情况下都是中继台的亚音设定出了些问题。
亚音频的设定
为了实现更大范围的覆盖，中继台一般都会架设在该地区内的制高点以获得尽可能远的无线电视界。而现在更有不少中继采用互联网或UV段链路的方式将很多中继台连接在一起，“一呼百应”。一个中继台上接收到你的信号，转发到多个中继台。
一个中继台机柜，下面的是双工器
很多中继台多采用同段转发，比如我们之前举的例子：439.750-5的中继台。为了使得这两个频率上的信号不互相干扰，中继台的天线系统要安装双工器以隔离两个离得非常近的信号，从而使得接收和发射能够使用同一根天线。而在管理上，中继台一般都能够使用DTMF信号（就是我们按下对讲机的按键时发射的音频）控制，从而实现远程控制的功能。
1988年我国首座业余无线电中继台通过电信网络与美国中继台网互联成功使业余手持对讲机从长城与美国和加拿大数以万计的业余电台实现对话
如果你想要日常使用中继台，其实只要弄明白其参数设定即可。但是如果你对其有着更大的好奇心，那么小小的中继台里面也还包含有很多无线电知识等着你去发现呢！一边玩着无线电，一边快乐的学习吧！
军用对讲机最远距离有几公里?
军用对讲机（既然你问的是对讲机，顾名思义就是手持对讲机了，那么在这里我就不提及步兵背负式电台和车载的大铁牛了）军用对讲机从频率上来说，大致分为 VHF--UHF段（近程）、30-80兆HF段（中近程）
至于每个频率段具体的机型就多了，咱不浪费时间介绍。
单兵、山地部队（或野战部队）一般使用VHF对讲机（具体功能不介绍，加密模块是标配）VHF段的频率在绕射能力和地波传播能力方面是很好的，但是其信号对建筑物的穿透力差！所以一般做为山地或野战单兵近程通讯使用，其通讯距离一般能保持在3-10公里左右
单兵、城市作战部队，一般使用UHF段，这个频率段的穿透能力很好，但是地波传播能力和绕射能力差于VHF，所以通常作为城市作战部队使用，其通讯距离城区和民用对讲机差不了多少2-3公里左右
指挥、单兵、山地、野战。最后这个是HF段，也就是30-80兆！这个频率段的对讲机相对比V/U段对讲机的列装数就少了很多了，毕竟适用的地区和部门不同。这个频率段要关注使用技巧了，也许对于大兵哥来说，关键时刻能呼叫到空中打击就可以了，并不在乎技巧云云的东西~~~这个频率段在传播好的时候一句话呼出几千公里很正常，传播差的时候也就十几公里，使用中，不计算技术与传播问题，其完整的话音信号可以在35公里以外清晰的听到。这就是HF的魅力！低于30兆的军用对讲机就没啦！（除非是定制的特种设备，咱真没玩过特种货！）
用120W的数字短波单兵背负式电台，用斜拉天线都可以进行1000公里的的有效通讯。当然，民用的同样可以做到，只不过民用的目前国内不允许用数字短波机器，就算目前的模拟信号的短波机器100W都可以喊全中国了！只要天线弄的好，没什么做不到的！很正常.
IP中继台发展
IP中继台可实现本地对讲信号中继，通过IP网络可实现语音实时性和PTT信号无错误的传输，无论在哪个城市，还是在VHF或UHF制式下使用，IP中继台可以将系统覆盖范围扩大到全球任一位置，轻松满足不同地理空间、不同频段，网络互联共享语音，实现一键式通话，从而解决了无线电传输中受传输环境、发射功率、接收灵敏度等约束传输距离的难题，不必再担心通信距离短、覆盖范围小的问题。
IP 中继台通过IP网络不但实现了超长距离无中继网络互联的目的，通过中继台同时可以实现在高耸林立的大楼里架构分布式对讲信号覆盖系统。
对讲机中继台案例
对讲机中继台，功率分为5W/10W/15W。要如何选择功率呢？首先，要根据所使用的环境；再者，现使用的对讲机功率这两点来选择改装中继台的功率。但并非功率越大越好。
简单的画出中继台的使用环镜案例：
这是城镇环境，某客户提供的信息，主要为对讲机延伸距离，达到远距离通话。从图可看出，通话范围直径是5km。因楼房较为密集，楼层不高的状态，造成对讲机通话距离受限。对讲机的功率是5w，发射距离为2~2.5km。将中继台架设在中点，使中继台能接收到对讲机发射的信号。这时可选择5w功率的中继台即可。
这个同样是解决对讲机通话距离的延伸。但所处的环境和地理位置不同。
此案例是解决信号盲区。
注意：安装中继台的必须满足一个条件，中继台必须安装在对讲机的发射信号范围内。简单来说就是，中继台的安装位置必须能够接收到对讲机的信号。这是安装所有中继台必须符合的条件。
High-frequency walkie-talkie and low-frequency walkie-talkie What is the difference ah?
The first is the difference in the frequency of work ah. There are some bands on the two bands that are allocated to the public and the unit, the frequency range used by the enterprise. So the work of the radio frequency band also concentrated in the 400-470MHz and 136-174MHz. Call distance 150MHz and 400MHz walkie-talkie in the city, then 400MHz walkie-talkie distance to go a little bit, because the antenna gain is higher than the 150MHz machine. In the mountains, then the 150MHz walkie-talkie distance is far away, because there is the existence of radio waves. Function on the words of the two kinds of walkie-talkie are similar.
The greater the output power of the transmitter, the greater the coverage of the transmitted signal, the farther the communication distance. But the transmission power can not be too large, the transmission power is too large, not only power consumption, affect the life of the amplifier components, and strong interference, affecting the call effect of others, but also produce radiation pollution. The radio power management agencies of various countries have clearly defined the transmission power of the communication equipment.
What is a high frequency walkie-talkie?
High-frequency walkie-talkie is a work in the short-wave frequency of high-end walkie-talkie, generally refers to the frequency of 400-470 walkie-talkie.
In the daily use of walkie-talkie, according to the provisions of the China Radio Regulatory Commission, radio frequency generally do the following division:
1, professional walkie-talkie: V section 136-174MHZ, U section 400-470MHZ;
2, the armed police with: 350MHZ;
3, Coast use: 220MHZ;
4, amateur use: 433MHZ;
5, cluster with: 800MHZ;
6, mobile phone: 900 / 1800MHZ;
7, the public walkie-talkie: 409-410MHZ.
Do you have to talk about high frequency or low frequency?
Just call the station is not to relay the direct call to the meaning of radio?
If it is used in the city, high-frequency signal penetration, so the general choice of high-frequency calls;
If it is used in the wilderness, low-frequency signal bypass ability, the general choice of low-frequency calls.
What is the maximum distance for civil walkie-talkies?
Civil walkie-talkie power 0.5-1W, usually the communication distance of about 1 km. But this also has great access. Communication distance and the environmental conditions between the two, such as electromagnetic interference has a great relationship. For example, one in the mountains, one on the ground, the middle line of sight without any obstacles, communication distance to more than 5 km. If the remote grassland communication distance can be very far, if in the city, due to obstacles, electromagnetic interference is serious, the communication distance is very close.
Ordinary civilian, domestic on the line, security, fire, guard what, the output power of 5 watts enough, open 3 km. Frequency points need to apply for no declaration, approved down to buy the corresponding frequency of the radio station. If you need a long distance call, you need to build a relay station, probably covering about 30 km in diameter (plain, no mountain block.)
Radio intercom station
The walkie-talkie relay station is used to increase the distance of the radio communication equipment, when the distance between the two walkie-talkie than the radio signal range, the walkie-talkie will not receive a valid signal, then, you have to use the walkie-talkie relay station. The role of the relay station is to receive the signal forwarded to complete the signal between the relay.
Walkie-talkie relay station, also known as the turntable, forwarding station, bad turntable, IP turntable, wireless communication system is an indispensable important equipment. Is in the wireless intercom system, used to increase the communication distance, expand the coverage of the equipment, such as the expansion of the car station, handheld radio range and communication capabilities, greatly improve your work efficiency.
Currently the most common popular relay station model:
Motorola GR300
Motorola GR3188
Motorola GR3688
Motorola CDR700
The current common brands are:
Motorola (MOTOROLA) relay station / turntable
Kenwood (KENWOOD) relay station / transit station
VITEX STANDARD repeater / relay station
Hytera repeater / transit station.
External antenna and feeder can form a complete relay system.
Bought a walkie-talkie, how can we laugh at the relay station?
For the new HAM, the first kind of equipment that makes us feel very magical may be a repeater - like all ham in the whole area ... And only wait until the first time and other HAM out to set up short-wave radio, or often participate in relay activities, the relay station halo will slowly fade, return to the daily use of the role of tools to go. What is the relay station inside?
A homemade relay station, you can see inside the two cars loaded
First of all we can from its performance to see some clues: the relay station can make a lot of radio stations can not communicate with each other "through", appeared in the same frequency. This is why it is named "relay Taiwan" reasons. An erection of a well-functioning relay station can hear the signal at an upstream frequency and transmit it again at another frequency (downstream frequency), so that all the friends who are listening to the downlink frequency can copy the Signal, and want to reply to a friend, the same frequency on the launch, so that through the relay station forwarding, the two could not communicate with each other's radio station to be able to complete a communication.
The use of repeater is generally very easy, all you have to do is to confirm the local radio relay frequency and parameters, and then write to your walkie-talkie can be. We just got the walkie-talkie, start their first pass when we only need to agree with a friend a good frequency can be. But if you use the walkie-talkie, but also enter the frequency difference and the tone. These settings generally appear in this form "439.750-588.5", this data is what does that mean?
We all know that when using the walkie-talkie two people can not speak at the same time, radio waves in the air "fight", who can not hear the signal. The use of the relay station is the same time, but for the relay station is "left leg trip right leg" type of interference, most of the relay station will use a different frequency to avoid their own transmission for their own received signal The interference. And the difference between the two frequencies is generally fixed. For the 430MHz segment, the frequency difference is generally 5MHz. While 144MHz, then the frequency difference is generally 0.6MHz. A downlink frequency (that is, the usual listening frequency) is 439.750 of the relay station, the uplink frequency is generally 434.750MHz.
Adjust the frequency difference option
While the tone (88.5Hz) is to avoid interference, imagine if the relay station for the uplink frequency of the signal unconditional forwarding, then the downlink frequency is bound to receive a lot of unwanted signals. So we set the relay station, so that it only forwards the signal contains sub-audio radio signal, we set the radio when the same time to set the sub-audio. So that when using the repeater station, the relay station only forwards those signals that contain sub-audio, that is to use the relay station, and ignore the other signals. Many friends just get the walkie-talkie, the old ham to remind "you did not go up relay!", In many cases are the relay station set up some of the problems.
Sub-audio settings
In order to achieve a wider range of coverage, the relay station will generally be set up in the region's high ground to get as far as possible in the radio sector. And now a lot of relay using the Internet or UV segment of the link will be a lot of relay station together, "one hundred call." A relay station receives your signal and forwards it to multiple repeater stations.
A repeater cabinet, the following is a duplexer
Many relay stations use the same paragraph forward, such as our previous example: 439.750-5 relay station. In order that the signals at these two frequencies do not interfere with each other, the antenna system of the repeater station is equipped with a duplexer to isolate two very close signals so that the same antenna can be used for reception and transmission. In the management, the relay station is generally able to use the DTMF signal (that is, we press the radio button when the launch of the audio) control, in order to achieve remote control functions.
In 1988 China's first amateur radio relay station through the telecommunications network and the US relay network interconnection success so that amateur walkie-talkie from the Great Wall and the United States and Canada tens of thousands of amateur radio to achieve dialogue
If you want to use the daily repeater, in fact, just to figure out its parameters can be set. But if you have a greater curiosity on it, then a small relay station which also contains a lot of radio knowledge waiting for you to find it! We can learn happily while playing with radio!
Military walkie-talkie up to a few kilometers away?
Military walkie-talkie (since you are asking the walkie-talkie, as the name suggests is holding a walkie-talkie, then here I do not mention infantry kneeling radio and car tai iron) military walkie-talkie from the frequency, roughly divided into VHF - UHF Segment (short-range), 30-80 MHz HF segment (medium proximity)
As for each frequency section of the specific models on the more, we do not waste time to introduce.
The frequency of the VHF segment is good in terms of diffractive capability and ground wave propagation capability, but its signal to the building is very good, but the frequency of the VHF segment is very good, The penetration of the material is poor! So generally as a mountain or field manuscript short-range communication use, the communication distance can generally be maintained at about 3-10 km
Man, the city combat force, the general use of UHF segment, the frequency of the penetration ability is very good, but the ground wave propagation ability and diffraction ability worse than VHF, it is usually used as a city combat force, the communication distance from the city and civil walkie-talkie Not much as much as 2-3 kilometers
Command, man, mountain, field. Finally, this is the HF segment, which is 30-80 trillion! This frequency section of the walkie-talkie relative to the V / U section of the radio installed a lot less, after all, the application of different regions and departments. This frequency section to pay attention to the use of skills, and perhaps for the soldiers brother, the key moment can call to the air blow can, and do not care about the skills of things ~ ~ ~ this frequency in the spread of a good time out of thousands of kilometers It is normal, the spread of the poor when more than a dozen kilometers, the use of technology and communication problems, and its complete voice signal can be heard in 35 km away. This is the charm of HF! Less than 30 trillion military walkie-talkie no! (Unless it is customized special equipment, we really did not play special goods!)
With 120W digital short-wave manned backpack radio, with cable-stayed antenna can be 1000 km of effective communication. Of course, the same can be done civilian, but the civilian domestic is currently not allowed to use digital shortwave machine, even if the current analog signal shortwave machine 100W can call the whole of China! As long as the antenna get good, nothing can not do! It is normal.
IP relay development
IP relay station can achieve local intercom signal relay, through the IP network can achieve real-time voice and PTT signal without error transmission, no matter in which city, or in the VHF or UHF standard use, IP relay station can be the system Coverage to expand to any location in the world, easily meet the different geographical space, different frequency bands, network interconnection to share voice, to achieve one-click calls, to solve the radio transmission by the transmission environment, transmit power, receiver sensitivity and other constraints of the transmission distance , Do not have to worry about the short distance of communication, coverage of small problems.
IP relay station through the IP network not only to achieve the purpose of ultra-long distance without relay network interconnection, through the relay station at the same time can be achieved in the towering building architecture distributed intercom signal coverage system.
Intercom repeater case
Walkie-talkie relay station, the power is divided into 5W / 10W / 15W. How to choose the power? First of all, according to the use of the environment; Moreover, the use of the walkie-talkie power to choose these two points to modify the relay station power. But not the greater the power the better.
Simple to draw the use of repeater ring mirror Case:
This is the urban environment, a customer to provide information, mainly for the walkie-talkie extension distance, to achieve long-distance calls. As can be seen from the figure, the call range diameter is 5km. Due to the building is more intensive, the floor is not high state, resulting in intercom call distance is limited. Walkie-talkie power is 5w, launch distance of 2 ~ 2.5km. The relay platform at the midpoint, so that the relay station can receive the radio signal. Then you can choose 5w power relay station can be.
This is also an extension of the distance from the radio to solve the talkie. But the environment and geographical location is different.
This case is to solve the signal blind spot.
Note: The installation of the repeater must meet a condition that the repeater must be installed within the transmitter's transmit signal range. In simple terms, the installation location of the repeater must be able to receive the signal from the radio. This is the condition that all the repeater stations must meet.