-Sanshui Cheyou.com (/bbs/index.asp)
-"discussion on the affairs in the station" (/BBS/list.asp? boardid= 14)
-Learn about radio (Radio Love Database) from here (/bbs/dispbbs.asp? board id = 14 & amp； id=9 1)
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-Author: Administrator
-Date of issue: 8: 59: 23 June 2005.
-Understanding radio starts here (radio wave love database)
Hehe, after a period of data collection, it's finally done. I hope it is useful to everyone! This is a way to make it easier for you to find information, with the purpose of serving as a database.
The theme of this new fixed-top radio communication is to make a connection post according to the use of forum software, so that everyone can consult relevant information conveniently. It is divided into several items: beginner's introduction, the history and correlation of ham friends, laws and regulations, the essence of this edition, radio technology, equipment description and equipment introduction. Each post is regarded as a project. I posted it according to the connection table made by Sister Auguste, the moderator of windmill (thanks to the inspiration of Auguste).
Because there are not many related articles in this version for the time being, it can only be improved gradually. Welcome to publish some good articles to sort out the posts on this topic. If you haven't done enough, please give me more evidence. I'm just a computer illiterate. I wish I could understand that.
There is no reply to this post. If in doubt, please open a new post. If you think you have something to add, please let me know by SMS and I will update it in time!
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-Author: Administrator
-Date of Issue: 8: 59: 55 June 28, 2005
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Common sense of interphone:
How far is the intercom? The communication distance of conventional walkie-talkies can reach 8 ~ 10 km at most in open areas and 3 ~ 5 km in general urban areas. In the case of tall buildings or mountains, the communication distance will be shorter. With network support, intercom can reach tens of kilometers. Networking is the use of relay stations (also known as base stations or turntables) to automatically receive signals from walkie-talkies and amplify and forward them. Networking can expand the communication coverage of walkie-talkies and extend the communication distance, which can reach 10-20km (handheld walkie-talkie) or even 30-50km (car walkie-talkie) in open areas. The building can cover heavily shielded areas, such as basements, underground parking lots and fire exits, which are often called dead ends.
Can mass consumers buy walkie-talkies? Mass consumers can also buy walkie-talkies, but before buying and using walkie-talkies, they must apply to the local radio management committee (hereinafter referred to as "no committee") to obtain a radio license and pay the frequency occupation fee. 200 1 65438+On February 6th, China opened the market of civil walkie-talkies and used 400MHz civil walkie-talkies with transmission power less than 0.5 watt without any formalities.
Can I make a phone call on the intercom? With network support, walkie-talkies can be used to make phone calls. However, if it is just a routine call between single machines, the function of making a phone call cannot be realized.
Common sense of walkie-talkie use:
Precautions for antenna use 1. Do not hold the antenna with your hands when using it.
2. The walkie-talkie antenna can't be unscrewed, otherwise the power tube will be easily burned when launching.
3. Don't use the damaged antenna. When launching, if the damaged antenna touches the skin, it may cause minor burns.
Precautions for battery use 1. Original or approved batteries should be used.
2. If metal conductors such as jewelry, keys or beads come into contact with the exposed electrodes of batteries, all batteries may cause damage or personal injury. Please use the charged battery carefully, especially when you put it in your pocket, wallet or other metal container.
3, charging must be carried out in the environment of 5~40 degrees. If it exceeds this temperature range, it will affect the battery life, and it may not be enough to charge to the rated capacity.
Electromagnetic interference/electromagnetic compatibility In order to avoid problems caused by electromagnetic interference and/or electromagnetic compatibility, the walkie-talkie should be turned off when the sign "Turn off the walkie-talkie" is posted. Such as hospitals or other places where health care medical equipment is used. When flying, the walkie-talkie should also be turned off as required.
Precautions for walkie-talkie operation:
When the walkie-talkie is transmitting, keep the walkie-talkie in a vertical position and keep the distance between the microphone and the mouth at 2.5-5cm. When launching, the walkie-talkie should be at least 2.5 cm away from the head or body. If the hand-held walkie-talkie is carried with you, the antenna should be at least 2.5 cm away from the human body when transmitting.
2. Don't switch it on and off many times during use, and adjust the volume to the volume suitable for your hearing.
Safety precautions for walkie-talkie use 1. In a car equipped with an airbag, do not put the walkie-talkie in the range that may be involved when the airbag is deployed. If the walkie-talkie is in the area that may be involved when the airbag is deployed, once the airbag is deployed rapidly, the walkie-talkie may hurt people in the car with great impact.
2. In a potentially explosive atmosphere or occasion, unless the walkie-talkie is specially certified, it must be turned off. In a potentially explosive environment, electric sparks can lead to explosion or fire.
3. Do not replace or charge the battery in an environment with potential explosion danger. When installing and removing batteries, contact sparks may occur and lead to explosion.
4. Turn off the walkie-talkie before approaching the blasting area and the area where the detonator is located, so as not to cause possible explosion.
Daily maintenance of walkie-talkie:
The walkie-talkie has been used for a long time, and it is easy to get dirty when pressing the button, control knob and casing. Please remove the control knob from the walkie-talkie and clean the casing with neutral lotion (do not use strong corrosive chemicals) and a wet cloth. The use of chemicals such as cleaning agents, alcohol, sprays or petroleum preparations may damage the surface and casing of the walkie-talkie. 2. Use the walkie-talkie carefully. Never move a walkie-talkie with a portable antenna. 3. When the accessories are not applicable, please cover the dust cover (if equipped).
Walkie-talkie technical assistant:
Can't talk to other members of the group?
First, confirm whether the frequency and sub-audio signals you use are the same as those of other members in the group; If there is no problem, please confirm whether other members of the group are in the service area.
Other players' voices appeared on the channel? Please change the tone of sub-audio, and at the same time, you must change the tone of all walkie-talkies in the group, or apply for changing the frequency point.
It won't take long after the battery is charged. The battery life has reached, please update the battery. (The normal charge and discharge times of Ni-MH battery are generally 500 times, and that of lithium battery is 1000 times. )
The intercom doesn't scan? When the walkie-talkie is programmed, the channel is not included in the scanning (set by professionals) or the whole machine scanning function is turned off.
Full band noise after programming? When the walkie-talkie is programmed, the mute is all turned on. Non-professionals suggest not to adjust the functional parameters.
Regular buzzing after programming? Interphone programming error. The programmed frequency exceeds the specified frequency range of the walkie-talkie, or the selected model and machine are not paid.
After using it for a while, the headphones became silent? The earplug socket of the intercom is broken. Send it to the maintenance station for repair.
Is the call distance getting closer and closer, and the sensitivity is poor? Check whether the antenna is intact and whether the antenna base is loose or damaged (please send it to the maintenance station for repair).
The walkie-talkie can receive the voice of the other party, but it can't transmit it. Check PTT button. Send it to the maintenance station for repair.
Can't open it or there is often no electricity? Check whether the interphone battery contact is deformed or damaged.
No display or error display on interphone with LCD? If the walkie-talkie is dropped or improperly used, the LCD is broken or the conductive rubber is in poor contact (send it to the maintenance station for repair).
Did the other party receive a small sound or an intermittent sound? Check whether the small hole in the MIC transmitting part of the walkie-talkie is blocked (if not, please send it to the maintenance station for repair).
Noisy intermittent reception? Reach the limit communication distance of walkie-talkie or there is a tall building blocking the basement. No, please send it to the maintenance station for repair.
How to deal with the water in the machine? Disassemble the machine first, and remove all external parts one by one (such as keys, PTT glue, light guide columns, etc.). ), carefully clean and dry the circuit board with absolute alcohol or special washing water, and clean the stains on the circuit board with gadgets; Then soak in anhydrous alcohol, and if possible, clean with an ultrasonic cleaner; Secondly, after taking it out, blow dry it with a hair dryer (be careful not to get too hot) and check whether the circuit board is damaged. If there is a broken wire, connect it with a thin enameled wire, and measure the positive and negative extreme resistance of the board power supply with a three-meter to avoid short circuit or open circuit (check the current, which is normally about 40MA, not less than1000 Ma); At launch); Finally, check whether the wireless port is dirty. If it is dirty, clean it up. At the same time, if there are other faults, repair them as usual. Generally, the water inlet machine with serious circuit corrosion can't be repaired, so it should be disposed of in time after the machine enters the water.
Solutions to common problems in debugging 1. Frequency interference: In use, there will often be crosstalk or noise from other stations, which will interfere with the normal use of walkie-talkies. There are three solutions: ① Change the frequency. ② Add subaudio or DTMF, etc. (3) Reduce the noise level (applicable to the situation that individual machines are disturbed under the same conditions)
2. Close range: When the communication distance of walkie-talkie is several meters different from the actual need, it can be realized by adjusting the machine power and mute level. When the adjustment still cannot be improved, consider adding a turntable to solve it.
3. Intermittent sound: Intermittent phenomenon often occurs in interphone communication at critical distance. At this point, you can adjust the mute level or cancel receiving sub-audio to test the effect.
4. Howling: When the distance is only a few meters or closer, the two walkie-talkies will howl. This is a normal phenomenon and can be solved by turning down the sound to an appropriate level.
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-Author: Administrator
-Release date: June 28, 2005 at 9: 00: 40.
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Simple concept and selection of radio station (vehicle platform/handheld platform)
The car platform/hand platform is a radio station, and the walkie-talkie we usually talk about is actually a radio station. There are usually many misunderstandings about names. For example, many people think that walkie-talkies are used in pairs, or that "radio" is a very profound thing, which is actually very easy to understand-including the radio part of the stereo installed in your car and the walkman radio, which are actually a big category.
I won't say much about the radio. I don't understand myself if I talk too much.
1, what is a radio station?
For frequency/frequency point/channel, you can briefly talk about it.
Think about the 97.4 103.9MHz that everyone usually listens to. This is the frequency. It may be true that the frequency point is a bit far-fetched, but it is a bit misleading to often say "103.9 channel, 97.4 channel".
In fact, the radio we listen to every day is broadcast, but it is transmitted through a "radio station". The radio station is extremely powerful, the transmitting antenna is in a very good position, and the coverage area is extremely wide, so all receivers (that is, radios) within its coverage area can receive its signal and convert it into sound to play.
Now imagine that you and your friends have a radio receiver and a radio transmitter in their car/hands, which is what everyone is talking about. It may be misspelled, but the word was invented anyway. At the same time, they have the functions of transmitting and receiving, so they can talk to each other.
2. Frequency/frequency/frequency band
97.4MHz is the frequency point of the music station, 103.9MHz is the frequency point of the traffic station, and 438.500MHz is the transmitting and receiving frequency point that Beijing amateur radio enthusiasts can legally use (in the 400MHz frequency band, there are also legal frequency points of amateur ham in other frequency bands, so I won't say much here).
Obviously, everyone's FM radio does not support reception above 430 MHz (it seems that the FM part is between 86- 107 MHz). So if you want to send and receive signals at the frequency of 438.500MHZ, you must have special equipment, that is, you need what you usually call "stations/hand stations/base stations that support amateur frequency bands" and so on.
If 438.500 is a frequency, it also belongs to the 430MHZ band. We probably call 430.000-439.999 amateur 400M band, also called amateur 70CM (cm) band (wavelength), because this band is mainly allocated to amateur radio enthusiasts.
The primary HAM may be exposed to "2m band" or "140 MHz amateur band", which is between144.000-145.999mhz, which is also the frequency band that HAM can use.
3. The difference and simple concept of amateur radio/professional radio/radio.
Not to mention the radio, which is used to monitor the signals from other transmitting stations. Generally, radio and frequency modulation (FB)/ amplitude modulation (AM) are two different modulation methods. Correspondingly, there are also these two modulation methods in the radio station. FM radio station supporting 430MHZ is commonly used, and air traffic control station uses 1 10 MHz-.
Let's talk about some simple differences between "amateur radio" and "professional radio"
The first floor means
Amateur radio stations are radio stations supporting amateur frequency bands-radio stations supporting (including) 430-440 frequency bands, and professional radio stations are radio stations supporting some other specific frequency bands.
On the other hand, amateur radio stations pay attention to "playing" and adjust various related parameters, including adjusting transmission power/searching for frequency points with signals/storing multiple different frequency points/manually changing stored frequency points at any time/adjusting different mute values/having a signal strength table, etc.
Professional radio stations pay more attention to the stability of use, so the requirements for the complexity of operation are relatively low, while the requirements for the durability of batteries/the stability of transmission power are higher.
In contrast, professional stations usually can't adjust the transmission power at will/have no function of searching frequency points/can store a small number of frequency points and can only display the channel number but not the frequency point value/need computers and special software and connections to adjust the frequency and related functions stored in each channel/usually have no signal strength table to display.
Moreover, professional radio stations may also add some safety measures such as FM or support relay in their design (I don't know much about it)
You just want traffic JC, arm JC and so on. They take a table and know which is the volume switch, which to press to speak, which channel to turn to is the squadron and which channel is the reception desk. If you give JC a fancy amateur radio station, he will be confused.
4. Repeater)/Offset and Direct Transmission
Some people may ask what "relay" is.
In this detail, we may talk about the diffraction of waves. I feel a little dizzy, too. I have returned it to the physics teacher. Suppose there is an antenna or a pair of antennas and a special transceiver station at the height, which is responsible for forwarding the signal received at one frequency point to another frequency point, then all stations within its coverage can contact it, that is, contact others through it.
Still dizzy?
Let's just say that the signals between two radio stations on the ground may not be transmitted to each other due to the obstruction of buildings/terrain, but two people can communicate well through this very high and well-located relay station, so that everyone can reach a wider coverage through the relay station and help small-power equipment to expand signals.
Usually, a relay station needs to use a pair of frequency points. One is to receive signals from users' hand stations or stations (uplink signals, such as 434.750 used by everyone in Beijing) and broadcast them on another frequency point (downlink signals, such as 439.750 in Beijing). Because the relay station must occupy a good geographical position and may have a relatively large transmission power, more people can be reached through the relay station.
Offset (offset)
The difference between 439.750 (user's listening frequency point, downlink frequency point) and 434.750 (user's radio frequency point, uplink frequency point) is the difference frequency. We can see that the transmitting point is the receiving frequency minus 5MHZ (-5MHZ), so it is called "downlink 5MHZ".
For some radio stations, the uplink frequency point and downlink frequency point can be set directly, and then stored in a channel for convenience.
Some stations set the reception frequency first, then set the difference frequency value and direction, and save it in a certain channel.
The setting method is not important, as long as you understand the concept of relay station/difference frequency, the rest can be solved by looking at the instruction manual of the equipment. Not much to say here.
straight hair
Usually, radio stations transmit and receive at the same frequency. The user switches the receiving/transmitting state of the radio station through the PTT (Push to Talk) key, presses the button to talk and releases listening.
Sending and receiving at a frequency point is called "direct transmission". For example, 438.500 438.550MHZ is a common frequency point for Beijing amateur radio direct transmission.
Of course, at the same frequency, only one device can transmit at the same time, and all other devices can receive it. If two people are transmitting at the same time, their signals will interfere with each other and cannot be heard.
4. Main points of purchasing amateur radio stations commonly used in racing.
Don't be superstitious about MOTO 6200C and some foreign-made FRS (Home Radio Service) home walkie-talkies, which are simply toys!
In order to avoid the interference of transmitting equipment to other frequencies, the power of these products must be less than 0.5 watts, and it may be able to reach a direct transmission distance of 2 kilometers without shielding. If it is in the city, 1 km is not bad. The only advantage is that you don't need any license plates and money detectors. You can use both when you buy them.
Of course, these handsets are fixed-channel and fixed-frequency transceiver devices, which can be understood as "low-power/non-adjustable-frequency professional radio stations (home)". Of course, their frequency is fixed at 409. (domestic) 462. /467。 ? MHZ (import) range, usually only 16 fixed frequency points, and cannot be changed. If your other amateur radio stations support these frequencies, you can communicate with them directly, but obviously, these little toys can't communicate with ham.
If you want to choose a radio station, you must meet the following conditions:
★ The covered frequency range must support (including) 430-440 MHz.
★ There must be a difference frequency function.
★ It is recommended to choose a machine that can set the frequency manually (that is, you can directly select the frequency point and store it freely in the channel without writing the frequency by computer).
★ It is recommended to support the subwoofer function.
★ It is recommended that the power be above 25W (vehicle platform)/support the maximum 5W (handheld platform) to ensure the communication distance.
With the above conditions, you can step into the ranks of ham (of course, you have to go through relevant legal procedures).
Common radio station selection reference
(The prices listed are for reference only)
Parameter noun explanation
Frequency range:144-146/430-440mhz frequency range.
Mode: FM working mode
RF power output: high: 2.5-6/2.2-6 watts, low: 0.5 watts, high: 50 milliwatts RF output (power).
Voltage: max. 13.8 VDC working voltage.
Current consumption:? MA working current consumption
Impedance: 50 ohm impedance
Size (w * h * d): 54 *112 * 33.5mm (with Pb-38) Appearance specifications.
Weight:? Kilogram weight
On the communication range of radio stations:
The communication range of a radio station is affected by many factors, such as the transmitting power of the radio station, the receiving sensitivity, the metal shielding of the car body, the surrounding environment, the shielding situation, the height, the type of antenna, the matching between the antenna and the machine, and even the temperature and humidity of the air. Any so-called "speaking distance" can only be used as a reference. For example, in Xiangshan, I used hams such as Jianwu F7E and Tianjin BG3AAX to communicate with 0.5W transmission power (equivalent to the maximum transmission power of MOTO6200C walkie-talkie in the market), but in the basement, I used 5 W transmission power, which was less than 200 meters from the ground and could not be received. The so-called "talking distance" of the walkie-talkie is actually a reference value under the condition that the flat ground is unobstructed. If used in urban areas, buildings and other places, the communication distance may be less than 1 km.
The reference of communication distance given below simply refers to the working environment in daily cities. For details, please summarize yourself in the future study of radio communication and related knowledge.
★ Entry-level mobile game platform
Price range: 300-400RMB Frequency range: 400-470MHZ(400M full section) No mute function Transmission power: For 2W general urban transmission range reference: 1-3km.
It is more suitable for entry-level DX to communicate around FB site, and the team will travel and listen.
Kington 3118 260 RMB (there are no ready-made pictures at present, please see other DX tables when FB, or who has them).
Lintong 7 1-B 300 yuan RMB
Whether Li Sheng 7 1-B 400 yuan has subwoofer function is unknown.
BFDX 5118,5118A (one with subwoofer, the price is about 300 RMB).
The appearance of 7 1B can refer to Jianwu 7 1A, but the workmanship is rough, the definition of function keys is different, and the internal software is completely different from Jianwu 7 1.
★★★★ Commonly used FB-class handtables
The maximum transmission power is 5W. The general urban transmission range is 2-5km.
Jianwu 7 1A
140m/400m two-stage transmitter
Price: about 1600 RMB.
References and pictures:/kenwood/thg71e.htm.
Main features:
Extensible frequency range: 140MHZ/400MHZ transmission, 100MHZ- 1000MHZ reception.
It is a relatively mature model and can be said to be the first choice for hand tables.
★★★★★★ hand platform for bag burning
The maximum transmission power is 5W. The general urban transmission range is 2-5km.
Jianwu F6A
140M/220M/400M three-stage transmitter
Price: about 2700 RMB.
References and pictures:/kenwood/thf6a.htm.
Main features:
You can listen to two frequencies at the same time and transmit at one of them.
0. 1- 1300MHZ reception, full modulation mode.
However, it is said that the launch of 220M is of little use. Besides, it's no different from F7E.
Jianwu F7E
140m/400m two-stage transmitter
Price: about 2900 RMB.
References and pictures:/kenwood/thf7e.htm.
Main features:
You can listen to two frequencies at the same time and transmit at one of them.
0. 1- 1300MHZ reception, full modulation mode.
Bazhongzhou
50-54/144-146/430-440mhz three-stage transmitter
Price: unknown
References and pictures:/yaesu/vx5r.htm.
Main features:
The launch of 50-54MHZ is of little significance to DX, which does not involve ham, and has little contact with this platform.
Bazhongzhou 7R
50-54/144-146/430-440mhz three-stage transmitter
50-54/144-148/222-225/440-450mhz (American version)
Price: 3600
References and pictures:/yaesu/vx7r.htm.
Main features:
All waterproof, the price in the hand desk is basically the highest.
★ Entry platform
The maximum transmission power is 35W. General urban transmission range reference: 5- 10km.
ADI 446
400-meter single-section platform made in Taiwan Province Province
Price: about 1600 RMB.
References and pictures: /adi/ar447.htm
Main features:
The function is relatively complete, and the frequency band is only 430-470MHZ, which is enough for DX to go out of FB.
There is a saying that ADI446' s hand-shrinking thread end is not good. I hope manufacturers will pay attention to this problem.
(Not available in the market)
Jianwu 46 1
400 m single platform
Price: about 2000 yuan
References and pictures: Not at present.
Main features:
It has always been the mainstream model of 400-meter amateur machine.
Complete function, frequency range of 400-470MHZ,
However, according to the news, it is no longer possible to determine that it is a 400-470 machine, and 46 1 is mostly extended to 400-470 by "opening the frequency".
M2 full-frequency machine can still be bought, but the price is about 200 higher than that of open-frequency machine. )
★★★ FB platform
I-COM 207H
140m/400m double-section platform
Price: unknown
References and pictures:/icom/ic207h.htm.
I can't buy it at present.
Bazhongzhou 90R
140m/400m double-section platform
Price: 3000 RMB.
References and pictures:/yaesu/ft90r.htm.
Main features:
The smallest two-stage platform in the world at present.
(Rare in the market)
★★★★★★ Bag burning platform
I-COM 2720
140M/400M two-section car platform, dual-frequency point listening.
Price: 2900 RMB.
References and pictures:/icom/ic2720h.htm.
Main features:
Bazhou8900/Bazhou8900r.htm
Jianwu TM-v 708/ Jianwu /tmv708.htm
Jianwu TM-V7A/ Jianwu /tmv7e.htm
Jianwu TM-D700A/ Jianwu /tmd700a.htm
For information about other radio stations, please check with www.RIGPIX.COM.
Supplement:
Radio model recommended by Tianxia Cheyou Automobile Club:
Handdesk entry level:
Puxing: PX388, the price is about 3 10 yuan. Features: 430 single-segment, sound recovery is good, and the cigarette lighter can get electricity.
FB level is usually used for handtables:
Jianwu 7 1A: the price is around 1600. Features: 144/430 two-stage mode, monitoring transmission, mature mode.
Kenwood F6A: The price is around 2700. Features: 144/220/430 three-stage, two-stage monitoring and simultaneous transmission, 0. 1- 1300 Hz full-stage monitoring. Lithium battery, full amplitude modulation, can receive FM broadcast signals.
Entry platform:
Jianwu 46 1A-M2, the price is about 2000. Features: 430-segment manual FM, classic model.
FB level of platform:
ICom2720, price: around 2900. Features: 144/430 dual-stage monitoring transmission, manual frequency modulation.
Icom208H, price: around 2900. Features: 144/430 double section, super transmitting power, U section 50W.
Bazhongzhou 7800, price: around 2500. Features: 144/430 double section, high transmission power, U section 40W.
Bazhongzhou 8900, price: around 3500. Features: HF 4-stage platform.
Jianwu V7A, price: around 4300. Features: 144/430 dual-stage monitoring transmission, manual frequency modulation. Large blue backlight screen, 280 storage channels. Simple operation function of five in one.
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-Author: Administrator
-Release date: June 28th, 2005 at 9: 001:09.
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Introduction to walkie-talkie use
Walkie-talkie, used for communication between players in outdoor activities, is very effective in places where mobile phones have no signal.
Power and communication distance of interphone:
The power of civil walkie-talkie is generally 0.5w, and the ideal communication distance is 3km, which will shorten the actual effective communication distance in the environment with building obstacles. This kind of walkie-talkie has the characteristics of small size and light weight, which is suitable for small-scale communication and outdoor activities of teams, without any communication expenses and saving expenses.
The power of professional walkie-talkies is generally 2w, the communication distance is 10 km, and the urban area is 3 km. .
Of course, it's all theoretical, but once in Bogda base camp, I used a police walkie-talkie of moto to clearly hear the conversation at the foot of the mountain: "Take them to the station", which made me break into a cold sweat.
Typical models of walkie-talkies:
Motorola, t6200c, Mickey/Princess, t5428, t5308 and other models are all civil 0.5w, and there are Bell, Haofa, Sword Dance and other models. However, the most popular are Motorola's civil aircraft, which are small in size, cheap in price and in civil frequency band, so there is no need to go through the formalities. Among them, 6200c conforms to the national open public frequency band without commission.
The price of walkie-talkie:
The price of several Motorola models is around 300-500. I bought Bell 99 160, 100. The 2w model is more expensive, 600-2000. Many mountain friends in mainland China buy Motorola's civil aircraft, which are light and cheap, and can also use batteries. Unlike our Xinjiang, we are still taking advantage of the public.
Intercom frequency:
Generally speaking, walkie-talkies have 10-20 channels, so as long as they are on the same channel, they can talk to each other, no matter how many. If a channel is unclear or there is interference, you can discuss changing to other channels. Don't forget to discuss it One changed, the other didn't, and he was blind.
The public frequency that the country opens to the public is 20 frequencies within 409mhz, and Motorola's 6200c is this frequency band, so it can be sold publicly in mobile phone stores. Many walkie-talkies adopt foreign frs (home walkie-talkie) specifications. For example, I bought Bell 99 160, and its working frequency is around 462mhz and 467mhz.
Although the frequency of frs does not meet the domestic standards, it is only 0.5w, and nobody cares whether you buy it or not. However, you can't communicate with Motorola's 6200c. Therefore, when going out for activities, there are more walkie-talkies. Let's try to communicate with each other first.
Remember, intercom calls are simplex (unlike telephones that are duplex). If you keep pressing the button and occupy the channel, others can't talk. Therefore, the popular walkie-talkie now is short message dialogue, and you can say something to me.
Intercom battery:
Professional machines use rechargeable batteries, such as mobile phones, nickel-metal hydride or lithium batteries; Most civil aircraft use ordinary batteries, aa or aaa, usually 3 to 4 batteries, and rechargeable aa or aaa is also acceptable.
According to outdoor experience, the life of a battery is generally two days, which is about 20 hours. Therefore, people with walkie-talkies are often seen shouting as soon as they arrive at the camp, asking everyone to turn off the walkie-talkie. It's best to equip it with rechargeable batteries. More investment at one time will pay off slowly. Otherwise, you will have to take 4 Fu Nan in one activity.
Use of walkie-talkie:
Generally, outdoor activities, more than a dozen people, with 2-3 walkie-talkies is enough, a captain, a scout, a defender, it's messy. More walkie-talkies become microphones and karaoke, which is even worse if a singer takes them.
Some people think that walkie-talkies are useless outdoors, but I disagree. The most important function of walkie-talkie is to enhance the confidence of the team leader and the whole team, know that the road ahead is easy or not, and know that the team behind will pull away the players, so that you can master the rhythm, which is very important for the happy March of the whole team.
To use walkie-talkies wisely, you have to master some walkie-talkie languages. Considering that the working mode of walkie-talkie is single and the field signal is unstable, you should try to simplify complex sentences and use Mandarin. Have you ever heard of Hou's cross talk?