Handheld walkie-talkie
This is a small size, light weight and low power consumption wireless walkie-talkie, suitable for hand-held or bagged, convenient for individuals to carry around, and can also communicate when traveling. Generally, its power does not exceed 5W in VHF band and 4W in UHF band. But there are also a few models whose power VHF is 6W and UHF is 5W, such as IC-T7H(VHF) is 6W. In an open area without obstacles, the communication distance can generally reach 5 kilometers. With the support of wireless communication network, the communication distance through the turntable can reach more than 10 km. This machine is suitable for close communication of mobile personnel in various occasions. In the wireless telephone series, the number and types of hand-held radios are the largest, accounting for more than 80%. From the high-end hand-held walkie-talkie produced by Motorola to the domestic low-end hand-held walkie-talkie with a price difference of about 100 yuan, it is estimated that this kind of walkie-talkie sells more than one million sets in China every year, which has great market potential.
Portable radio interphone
This is a kind of wireless walkie-talkie which can be installed on vehicles such as cars, ships and planes, and is directly powered by the power supply on the vehicles, using the antennas on the cars, ships and planes. Mainly used in transportation, production scheduling, safety command and other services. Its volume is large, and its power is not less than 10W, generally 25W. The maximum power is 56W for VHF and 50 W for UHF. There are also some vehicle-mounted platforms with a power of 75W(IC-VX8000) in a certain frequency band. The power supply of the vehicle platform is 13.8V, and the communication distance can reach more than 20km. In the wireless communication network, the communication distance through the turntable has obviously increased, reaching tens of kilometers. The sales price ranges from domestic 1000 yuan to imported machine 3000 yuan. It is estimated that the domestic annual sales volume is not less than 654.38+10,000 units. With the rapid development of transportation, especially the increase of private cars, the number of car-mounted machines (belonging to amateur radio enthusiasts) purchased by individuals will increase day by day. In 2003, amateur radio enthusiasts in Beijing alone bought no less than 2,000 mobile phones (including two mobile phones).
Forward interphone
Repeater walkie-talkie is to transmit the received signal of a certain frequency band directly through its own transmitter at other frequencies. The two groups of signals with different frequencies do not affect each other, or two groups of users can be allowed to communicate on different frequencies. It has the characteristics of full duplex operation, that is, transmitting and receiving work at the same time without interference. The English name of repeater wireless phone is repeater Transeiver, and the Chinese names are Repeater, Repeater and Repeater. Its biggest feature is that it can effectively expand the communication range and capacity of mobile phones, vehicle-mounted machines and fixed stations in the communication system, and provide a larger coverage radius for the system. Because this kind of equipment is unattended when working, some transfer stations are still placed on high mountains, and the working environment is poor, and some transfer stations are in the launching state for a long time. Therefore, the technical design requirements of the turntable are much higher than those of the vehicle-mounted machine and the fixed table, and there are even some special requirements, such as high stability, high reliability and good heat dissipation, which can work stably for a long time under high and low temperature conditions. Many devices have the function of automatically starting standby power supply or switching to DC power supply to continue working when the main power supply fails. The power of special turntables used in wireless communication systems is relatively large, generally ranging from 25 W to 50 W or even reaching 100W (TB8100W of Daji Company), and the power of small turntables used in buildings generally does not exceed 25W. ..
The development history of turntable is only more than 20 years. With the birth of new devices, new processes and new circuits, the application of new technologies in turntable design has continuously improved its technical level, quality and function. In 1984, the turntable represented by FTR 1045 produced by yaekju company in Japan and IC-RP 1520 produced by ICOM company in Japan adopts the crystal oscillation frequency doubling method. At 1985, KG 1 10 produced by KYODO, UP450/PCV 150 produced by SELKL, and RP 172 br/RP 565438+ produced by marantz. Since then, the technical level and function of the turntable have been greatly developed. Today, the excellent performance and high reliability of KG 1 10 are still praised by people in the industry. 1987, Jianwu also introduced TKR720/820 and later TKR828(350M), TKR830 and other turntables. TKR series turntable in Jianwu adopts advanced PLL frequency synthesis technology and CPU control technology, and all data are stored in EEPROM, which has more functions, stable and accurate frequency, and surface mount components technology is widely used. During this period, RP80 series pedestal/turntable and RP5 13 pedestal/turntable produced by Japanese marantz Company also entered the China market one after another. The turntable in RP5 13 adopts microprocessor control technology, which can provide automatic self-test function, and the power can reach 80W at 50% duty cycle. Among many turntables, Jianwu TKR720/820 series turntables are deeply loved by domestic professional users with good cost performance, and the market share is also the largest, which can be said to be a classic product in turntables. 1At the end of 1998, GR 1225 series turntable developed by Motorola Company of the United States was put into China market one after another. Adopting broadband technology and voice pressure control technology, the debugging parameters are all software, which greatly improves the comprehensive performance of the turntable, improves the frequency stability, makes the channel interval of 25KHE and 12.5KHE compatible, and improves the frequency utilization rate. In recent years, new turntable replacement products have also been listed one after another, and TKR750/820 turntable produced by Jianwu Company has replaced TKR720/820. KG5 10 developed by Japanese cooperation company was put into China market in 2000, and the production of KG5110 was stopped. KG5 10 inherits the characteristics of high reliability of KG5110, adopts CPU central microprocessor, and also has the function of wireless remote channel switching, continuously transmitting 50W power. T800 turntable produced by TAIT Company in New Zealand is also welcomed by special users because of its unique plug-in structure and high power of 100W. Vitex Company of Japan also introduced VXR7000 turntable at the "Communication Olympics" exhibition in 2003. In 2002, the "SPECTRA" professional pedestal/turntable MX800 produced by Spectra also entered the China market through domestic agents. This company is a world-famous company specializing in manufacturing radio communication equipment, and its products have passed ten international certifications. MX800 turntable adopts a series of new technologies such as military-grade modular structure, high-speed locking and high-speed launching technology, which can realize remote control, remote setting and monitoring self-diagnosis. Its frequency range includes all frequency bands within 30-960MHE, the frequency stability is 1PPm, and the launch start time is less than 4 ms The TB8 100 pedestal/turntable recently launched by Daji Company of New Zealand adopts the most advanced digital communication technology (RISC processor and DSP digital signal processor), and its power ranges from 5W and 50W to100W. Communication working modes are divided into simplex and duplex.
Simplex interphone
Simplex communication means that information can only be transmitted in one direction at the same time. You say I listen, I say you listen. This kind of transmitter and receiver can only work alternately, and the radio interphone that can't work at the same time is called simplex. The simplex works by controlling the conversion between receiving and sending with keys. When the transmission control key is pressed, the transmission is in the working state and the reception is in the non-working state; On the contrary, when the transmit key is released, the transmit is in a non-working state and the receive is in a working state. Simplex can be divided into simplex with the same frequency (or single frequency) and simplex with different frequency (or dual frequency, quasi-duplex and half-duplex) according to the frequency usage. Co-frequency simplex means that transmitting and receiving work at the same frequency. Its advantages are: using only one frequency can make the most effective use of frequency resources, because the transceiver works intermittently, the circuit design is relatively simple and the price is relatively cheap. The disadvantage is that both sides have to take turns to speak, that is, we can't speak until the other side has finished speaking. It is not as convenient and customary to use as calling. But as far as the utilization of frequency resources is concerned, simplex machine is the mainstream model. Different frequency simplex is only used in wireless communication systems with turntables. Now many simplex machines can work at the same frequency or at different frequencies.
Duplex walkie-talkie
Duplex communication means that information can be transmitted in two directions simultaneously. Just like talking on the phone, you can also listen while talking. This kind of diplexer, in which the transmitter and receiver can work at two different frequencies at the same time (the difference between the two frequencies has certain requirements), is also called different frequency diplexer. Duplex machine includes duplex mobile phone, duplex vehicle-mounted machine and duplex base/turntable. Duplex mobile phones mainly work in VHF and UHF bands. Duplex mobile phones are generally called cross-section duplex mobile phones. When working, it is either UHF transmission or UHF reception, or UHF transmission and VHF reception. However, the duplex vehicle-mounted machine and the base/turntable do not have this problem, and they can work in cross-section duplex or make it (VHF or UHF).
Band) of the same frequency diplexer. Because the diplexer is used to isolate and transmit signals or the dual antennas are used to separate and transmit signals, in VHF and UHF bands, as long as there is a certain frequency difference (national VHF band is 5~7MHZ, UHF band is 10MHZ), the same frequency duplex work can be completed. Although duplexers are easy to use, the circuit design is complicated and the price is high, especially in the use of frequency resources. Therefore, apart from using the duplex machine (receiver and base/turntable) in special occasions, the duplex vehicle-mounted machine has hardly been used in domestic professional communication (in some industries in the 1980s, such as imported models and domestic models such as water conservancy and power system UP450, KG 106). By the 1990s, most of them were no longer used. Duplex used in special occasions is a turntable for forwarding or a base station for command. Another feature of the duplex machine is that as a duplex base station, it can realize the connection between wireless network and wired network through interface equipment. This interface device has only one wireless connector (or adapter). Through it, wired phones can talk to wireless walkie-talkies, and conversely, walkie-talkies can make wired calls by dialing. This kind of equipment was very popular in China in the late 1980s and early 1990s. At this point, the simplex machine cannot be realized. Because the transceiver of simplex is the same frequency. In the full-duplex trunking communication system in the mid-1990s, the cross-section trunking duplex hand-held walkie-talkie and car phone called "Small Mobile" had a short time. The radio frequency point of its base station is UHF band, and the receiving frequency point is VHF band. On the contrary, the radio frequency point of the mobile station is VHF band, and the receiving frequency point is UHF band. These cross-section duplex hand-held walkie-talkies include IC-W2 1AT, IC-T2 1CP/T3 1CP from ICOM Company of Japan, TH-78A/79A from Jianwu Company of Japan, AT68C/88C and X98C from ADI Company of Taiwan Province Province, and TH82 from Shenzhen Tianlitong Company. Cross-section cluster full-duplex vehicle-mounted platforms include IC-28 1H/48 1H of ICOM company of Japan, TK-733 of Jianwu company of Japan, TH8 1 1 of Shenzhen Tianlitong company, and MR588 of Taiwan Province ADI company. In the late 1990s, with the popularity of "mobile phone", the reduction of price, the reduction of volume, the convenience of use and the increase of functions, the cross-section duplex trunking communication system was quickly eliminated from "* * * network" to "private network", and only a few dedicated cross-section duplex trunking communication systems are currently in operation. From the technical design, it can be divided into analog walkie-talkie and digital walkie-talkie
In terms of design technology, radio walkie-talkies can be divided into analog walkie-talkies designed with analog communication technology (also known as traditional walkie-talkies) and digital walkie-talkies designed with digital technology.
Analog walkie-talkie
The analog walkie-talkie modulates the stored signal to the transmission frequency of the walkie-talkie. The very mature analog technology in walkie-talkie technology will continue to serve the design of walkie-talkie for a long time and develop in the direction of small size, low cost, strong function and more commercialization.
To meet the different needs of communication users.
Digital interphone
Digital walkie-talkies digitize voice signals and transmit them in the form of digital coding, that is, all the modulation on the transmission frequency of walkie-talkies is digital. Only walkie-talkies that directly use digital signal processors are real digital walkie-talkies, and walkie-talkies that use digital control signals (such as trunking system walkie-talkies) are not digital walkie-talkies.
Digital walkie-talkies have many advantages. First, it can make better use of spectrum resources. Similar to cellular digital technology, digital walkie-talkie can load more users on the designated channel, such as 25KHZ, and improve spectrum utilization. This is a solution to frequency congestion, which has long-term significance. The second is to improve the voice quality. Because digital communication technology has the function of error correction in the system, compared with analog walkie-talkie, it can achieve better voice and audio quality in a wider signal environment, and the received audio noise will be less and the sound will be clearer. The last point is to improve the integration of voice and data, and change the weakness that the control signal decreases with the increase of communication distance. Compared with similar integrated analog voice and data systems, digital walkie-talkie can provide better data processing and interface functions, so that more data applications can be integrated into the same two-way wireless communication base station structure, and the integration of voice and data services is more perfect and convenient. These three characteristics make digital walkie-talkie become the inevitable trend of future walkie-talkie technology development. In the 1970s, Motorola took the lead in introducing digital technology into the design of walkie-talkie system, produced DVP walkie-talkies with digital voice encryption in 1975, developed a digital data communication system in 19 1 and used 35,000 digital walkie-talkies in1operation desert storm. Obviously, with the development of radio communication technology, the improvement of people's requirements for wireless communication quality and the increasing frequency spectrum resources, digital walkie-talkies will have a huge demand market.
However, no matter how widely the digital walkie-talkie is used, the mature analog technology will still serve the design of walkie-talkie for a long time, and develop in the direction of small size, low cost, strong function and more commercialization to meet the different needs of communication users. It is impossible for digital walkie-talkies to replace analog walkie-talkies in a short time. These two kinds of walkie-talkies will develop their own characteristics and develop together. From the equipment level, it can be divided into amateur radio and professional radio.
Amateur radio interphone
A radio walkie-talkie specially designed and produced to meet the needs of radio enthusiasts. This kind of walkie-talkie can also be called "playing computer". In view of this amateur personal radio service, all countries have opened up special frequency bands for amateur radio sports enthusiasts to use. China's open frequency bands are 144~ 146MHZ and 430~440MHZ, which are basically the same in the world. The Radio Frequency Planning of People's Republic of China (PRC) issued by national radio administration bureau, Ministry of Information Industry, in 20061October 5438+0 specifically explained amateur radio enthusiasts and amateur services. "Amateur service: a radio communication service for self-training, mutual communication and technical research for amateur radio enthusiasts. Amateur radio enthusiasts refer to people who are officially approved and interested in radio technology. Their interests are purely personal hobbies and do not involve profit. "
Because of the limited frequency range of radio interphone, the environmental conditions and requirements used are different from those of professional interphone. The main features of amateur machine are small size, complete functions, frequency scanning, direct setting of frequency on the panel and display of frequency points on the panel. Its technical index, equipment stability, frequency stability, reliability and working environment are also worse than those of professional radio stations. The direct result is that the cost of amateur machines is also lower to meet the needs of individual purchases. At present, most of the amateur machines used in China are imported equipment. Except for Motorola's two hand-held walkie-talkies AP50 and AP 10, which entered the domestic market in the mid-1990s, and Taiwan Province ADI's AR- 146/446 car platform and S- 145/450 handset, these devices are all made in Japan. These amateur car owners are: TH22A/42A hand-held walkie-talkie of Jianwu Company of Japan, TM26 1/46 1 car platform of Tron Company of Japan, DR 130/430, DR 135/435 car platform. Handheld walkie-talkies such as FTC2008/7008 and VX 150 from Yaekju Company of Japan, IC IC-)2 100H car platform from ICOM Company of Japan, and C 150/450 handheld walkie-talkie from marantz Company of Japan, etc.
Amateur machines generally have a feature, with a wide working range and frequency, and can work in the full range of V and U segments. V segment 136~ 174MHZ, and u segment 400~470MHZ. However, its technical indicators are only guaranteed in amateur frequency bands. For example, the actual working range of the DR435TG amateur machine of Japan Telong Company is 136~ 173.995MHZ, but its technical index can only be guaranteed in the amateur frequency band of 144~ 147.995MHZ. Similarly, the technical index of the DR435TA professional machine is/kloc-. If you want to use it in other frequency bands, you'd better re-debug, especially the power, otherwise the power will drop a lot. Because the price of amateur machines is lower, some professional users also choose amateur machines as their own models. At this time, it is best to ask an experienced engineer to re-debug it to ensure the performance index in the working frequency band.
Professional radio interphone
Most users of professional radio are used for the professional business of group teams. Therefore, the characteristics of professional walkie-talkies are simple and practical. A variety of communication interfaces are reserved in the design for users to carry out secondary development. Most of its frequency report settings are programmed by computers, so users can't change the frequency. Its panel only shows the number of channels, not the frequency points directly, so it has good frequency confidentiality, high stability and is not easy to run. In the long-term work, it has high stability and reliability, and the working temperature range is wide, generally from -30 degrees to +60 degrees. When the professional machine works in VHF band, it belongs to part of V high band (148~ 174MHZ) and V low band (136~ 160MHZ). The other part is the whole section (136~ 174MHZ). But in UHF band, most of them are divided into U high band (450~470MHZ) and U low band (400~430MHZ), and a few are U full band (400~470MHZ). The performance, reliability and stability of professional machines are higher than those of amateur machines, and the price is naturally higher than that of amateur machines, and some are even much higher. Except some domestic professional machines, most of them are imported models. The models produced by Motorola are almost all professional machines. The representative products are GP88, GP88S, GP2000, GP328/338 hand-held walkie-talkies, GM950, GH300, GM338/398 car-mounted platforms, T2000 series car-mounted platforms of Daji Company in New Zealand, KG series car-mounted platforms and handsets of KYODO Company in Japan, and Jianwu Company in Japan. F-series hand-held walkie-talkie and vehicle platform of ICOM company in Japan. There are many hand-held walkie-talkies produced in China.
The models are all carried out according to the design standards of professional machines, and there are not many models that really reach the level of professional machines. The gap is not only in the design technology, but also in the quality of components, the level of manufacturing technology and assembly technology, the processing quality of parts, the selection of materials (such as the plastic of chassis), especially the environmental test of products. As a professional machine, it must pass strict environmental tests according to standards. Many imported machines are tested according to the US military standards MIL-STD8 10C, D, E, and MIL-STD8 10 is the performance standard of products recognized by the US military in harsh environment. Its tests include low pressure, high temperature, low temperature, instantaneous temperature, sun exposure, sun protection, moisture prevention, salt spray, dust prevention, shock prevention and impact prevention. MIL-STD8 10E is an upgraded version of Advantages 0C and 8 10D. Some imported models are tested according to the European ETIS standard. Motorola's walkie-talkies have to undergo "accelerated aging test" before leaving the factory, that is, they simulate five years of actual bad use and meet the impact, shock, dust, moisture and IPX4 sealing tests of ELA-3 16B standards. In this respect, it is obvious that there is a big gap between domestic machines. Some lack conventional testing conditions, some have low testing standards, and some have no such testing awareness at all. Amateur machines will certainly not make much effort in this respect. The quality gap between professional and amateur machines is also obvious. For example, the working temperature of a professional machine reaches -30 degrees, while that of an amateur machine generally only reaches-10 degrees. It is not difficult for us to understand the price difference between professional machines and amateur machines, domestic machines and imported machines, professional machines and professional machines, brand machines and non-brand machines. From the communication business, it can be divided into public walkie-talkies, digital walkie-talkies, police walkie-talkies, aviation walkie-talkies and marine walkie-talkies.
Public radio intercom
Public interphone, commonly known as civil interphone. This refers to the walkie-talkie that can only work on the radio frequency designated by the government radio management department for public use. In essence, it belongs to the category of personal business communication, and it is a short-distance radio communication service for individual families or small groups. Anyone can choose to use the public walkie-talkie without approval, frequency occupation fee and call charge. However, this kind of public walkie-talkie has clear regulations on frequency, power and technical indicators. At present, China is formulating the national standard "Technical Specification and Measurement Method of 400MHz Public Intercom". It is reported that the national standard of public walkie-talkie in China refers to the 95th part of American FCC standard 47 crr- Personal Radio Service, including seven aspects. Comparatively speaking, China's public walkie-talkie is equivalent to its second content-family radio service (FRS), so the standard of public walkie-talkie in China is mainly formulated with reference to the relevant standard "FRS" in the United States. Europe also has corresponding standards for public walkie-talkies. Although the standards of different countries are different, one thing is the same, that is, the level does not exceed 0.5W In terms of frequency, there are great differences. Each country or region stipulates or implements its own frequency and channel number. The number of open channels in China is 20, and the frequency range is 409.750 to 409.9875 MHz. The United States has 14 frequency points, which are divided into two groups of 462MHz and 467MHz, with 7 frequency points in each group; There are also 14 frequency points in Taiwan Province province, ranging from 446.00625 MHz to 446.09375 MHz. There are 80 open frequency points in Thailand, ranging from 245.000 MHz to 245.7375 MHz. It is understood that Japan and South Korea adopt the public frequency stipulated by the United States. In addition, as a public walkie-talkie, the technical specifications of various countries stipulate that the front panel of the walkie-talkie cannot be set with programming operation function, in order to prevent it from being used.
Users can arbitrarily expand the frequency range and modify the working parameters. According to the regulations, the public walkie-talkie can only display the number of channels, not its working frequency. At the same time, it is also stipulated that public walkie-talkies can use infrasound technology (CTCSS) below 300HZ, commonly known as anti-jamming code or dedicated line, to prevent interference from the same frequency walkie-talkies.
According to the Regulations on Radio Management in People's Republic of China (PRC), Regulations on the Administration of Imported Radio Transmitting Equipment and Regulations on the Administration of Production of Radio Transmitting Equipment, public walkie-talkies sold in the domestic market, whether imported or made in China, must be tested by the National Radio Testing Center, meet the relevant national management regulations and technical standards, and obtain the type approval certificate of radio transmitting equipment issued by the Radio Administration of the Ministry of Information Industry. According to statistics, nearly 60 models of public walkie-talkies from nearly 30 manufacturers have been approved. But there are still many manufacturers to do this work, most of which are domestic machines.
Attached are some contents of FRS standards related to American public walkie-talkies:
95. 19 1FRS rules 1- qualifications and responsibilities: it is stipulated that no license shall be issued and channels shall be enjoyed.
95, 192FRS rule 2- approval place: the radio business is in any area of the world managed by FCC.
95, 193FRS Rule 3-Communication Type: Two-way voice communication, which can be established or maintained with sub-audio continuous tones below 300Hz. All channels give priority to urgent messages at any time and are not interconnected with the public switched network.
95, 194FRS rule 4- home radio service unit, only products with FCC approved labels can be used.
Its technical specifications are:
Channel frequency of 95 and 627FRS units: divided into two groups: 462MHz and 467MHz, and each FRS unit must keep the frequency tolerance within 0.00025%.
95,631emission type: one FRS unit can only emit F3E emission type. In order to establish or maintain microphone communication, non-voice transmission is limited to selective calling or mute.
95,633 emission bandwidth: F3E emission type emitted by FRS unit, and its approved bandwidth is 12.5KHz.
95,637 modulation specification. The FRS unit of the emission F3E shall not exceed the peak frequency offset of 2.5KHz, and the audio response shall not exceed 3. 125KHz.
Maximum emission power is 95,639 639: FRS unit shall not exceed 0.5W effective radiation power (ERP) under any modulation conditions.
95, 647FRS unit transmitter antenna: The antenna of each FRS unit must be an integral part of the transmitter, and the antenna should have no gain (compared with half-wave dipole) and be vertically polarized.
95,649 power supply: FRS units should not provide power supply to increase their transmission power to any level beyond the limit (0.5W) set by 95,639.
95.65 1 requires crystal control: except for R/C radio station, FRS unit and LPRS unit which transmit at the frequency of 26-27MHz, crystal control is applicable to all transmitters used for personal radio service.
China public intercom standard frequency point
Channel 1234556789 10
Frequency (megahertz) 409.7500 409.725 409.509.40977585845
Channel112131415171920.
Frequency (megahertz) 409.8750 409.875 409.9000 409.838+025 409.5095889896
American public intercom standard frequency point
Channel 1 2 3 4 5 6 7
Frequency (megahertz) 462.5625.57756656365
Channel 8 9101121314.
Frequency (megahertz) 467.5625.56775565676
European public walkie-talkie standard frequency point
Channel 1 2 3 4 5 6 7 8
Frequency (MHz) 446.0025 446.438+0875 446.438+025.408888888986
Taiwan Province Province Public Intercom Standard Frequency Point
Channel 1 2 3 4 5 6 7
Frequency (megahertz) 467.5438+025.50089.00000000005
Channel 8 9101121314.
Frequency (MHz): 467.6000 467.125 467.650.500505050506
Digital interphone
Police walkie-talkie
Aviation interphone
Marine walkie-talkie