In outdoor activities, the role of the walkie-talkie is in some cases greater than that of a mobile phone, it does not need the support of an external base station, can communicate freely with teammates in most harsh environments, and some also have three rugged and GPS functions. In times of great disaster, walkie-talkies can not only send distress signals, but also be used to listen to external information, as a PSK, to understand some walkie-talkie knowledge, and reserve a pair of walkie-talkies for backup is still necessary.
For friends who often travel, the walkie-talkie (handset) must be no stranger.
Generally, friends who are dating will have more than one unit to maintain the cohesion of the team.
But what kind of hand table is suitable for donkeys like us who travel a lot?
What is Walkie-Talkie:
The English name of the walkie-talkie is two way radio, it is a two-way mobile communication tool, without any network support, you can talk, no phone charges are generated, suitable for relatively fixed and frequent call occasions.
How to identify a civilian walkie-talkie:
Answer: All those with LCD screens, digital display tubes, and intercom with digital buttons are civilian walkie-talkies. The frequency range is between 100 and 500 MHz and can be shielded by new shields.
Frequency range of the walkie-talkie:
In the daily use of walkie-talkies, according to the regulations of the China Radio Regulatory Commission, walkie-talkie frequencies are generally divided as follows:
Professional walkie-talkie: V-segment 136-174MHz; U-segment 400-470MHz;
For armed police and public security: 350-390MHz;
Coastal: 220MHz;
Traffic light monitoring, air defense sirens: 223025-235mhz
Amateur: 433MHz;
For clustering: 800MHz;
Mobile: 900MHz 180MHz;
Civil: 409-410MHz
According to electromagnetic theory, the lower the frequency and the longer the wavelength, the weaker the ability of radio waves to penetrate buildings, but the stronger the diffraction ability; The higher the frequency, the shorter the wavelength, the stronger the ability of radio waves to penetrate buildings, but the weaker the diffraction ability. Therefore, in the city, because of the high density of buildings, the radio wave penetration is required, so the higher the frequency, the more suitable; However, when using walkie-talkies in open areas such as the wilderness or the sea, it is necessary to diffraction radio waves with strong diffraction ability, so it is more appropriate to choose the V-segment (136-174MHz).
How to use the walkie-talkie:
1 When the walkie-talkie is transmitting, keep the walkie-talkie in the vertical position and keep the microphone with the mouth 25-5 cm distance. When firing, the walkie-talkie is at least 2 days away from the head or body5 cm. If the handheld walkie-talkie is carried on the body, the antenna should be at least 2 miles away from the body when transmitting5 cm.
2 Do not turn on and off the computer multiple times during use, and adjust the volume to the volume that is suitable for your hearing.
The factors that affect the distance and effect of walkie-talkie calls are as follows:
1 System parameters.
1) The stronger the output power of the transmitter, the greater the coverage of the transmitted signal and the farther the communication distance. However, the transmitting power should not be too large, the transmitting power is too large, which not only consumes power and affects the life of the amplifier components, but also has strong interference, affects the call effect of others, and will also produce radiation pollution. The radio regulatory agencies of various countries have clear regulations on the transmission power of communication equipment.
2) The higher the receiving sensitivity of the communicator, the farther the communication distance.
3) The gain of the antenna, when the antenna is matched with the machine, as is often the case, the antenna height increases, and the reception or transmitting ability increases. The antenna used in handheld walkie-talkies is generally a spiral antenna, which has a smaller bandwidth and gain than other types of antennas, and is more susceptible to human influences.
2 Environmental factors.
Environmental factors include paths, density of trees, electromagnetic interference in the environment, buildings, weather conditions, and terrain differences. These and several other parameters directly affect the field strength and coverage of the signal.
3 Other influencing factors.
1) The battery is low. When the battery is low, the call quality deteriorates. In severe cases, there will be noise, which will affect the normal call.
2) Antenna matching. The frequency band of the antenna is inconsistent with the frequency band of the machine, and the impedance of the antenna does not match, which will seriously affect the call distance. For users, when switching to walkie-talkie antennas, pay attention to tightening the antenna, and do not use antennas that are not provided by the manufacturer, nor can you use antennas that do not meet the frequency of the machine.
4 The quality of the sound.
It mainly depends on the pre-emphasis and de-emphasis circuits, and there are also more advanced speech processing circuits "application of voice compaction circuits and low-level expansion circuits", which have a good effect on fidelity speech.
Walkie-talkie function terminology explained
1.Monitor
A type of listening used to receive weak signals. By pressing the special key to force the receiving signal channel on, the operator uses his ears to distinguish the weak sound in the speaker to achieve the purpose of listening.
2.Scan
A listening method used to hear calls on all channels.
By pressing the dedicated key, the receiving circuit is made to receive the signal in the channel by channel in a certain order for a period of time. If the reception time of each channel is 100ms, ten channels can be scanned per second, that is, the scanning speed is 10ch s.
3.Priority channel scan
The set priority channel is scanned first during the scanning process.
4.Delete Add Scan Channel
Removes or adds a channel from the scan list.
5.Voice-activated (VOX).
When this function is activated, there is no need to press the PTT key, and the transmit operation can be initiated directly by voice.
6.Launch time-out function (TOT: Time Out Timer).
This function is used to limit the user's overtime transmission on one channel, and also to avoid damage caused by long-term transmission of the walkie-talkie.
7.Battery S**e
In order to save electricity and extend the standby time, the walkie-talkie will work in the way of shutting down for a period of time and turning on for a period of time without transmitting acceptance and key operation, which is called power-saving mode. The ratio of the power on and off time is about 1:4. When the signal is received or there is a key operation, the walkie-talkie immediately exits the power-saving state and enters the normal state.
8.High low power selector
This function allows the user to choose between high or low power depending on the situation.
9.Busy channel lockout
When using this feature, the user disables transmitting signals on busy channels.
10.Squelch level
The strength of the noise in the received signal corresponds to the strength of the signal, and the stronger the signal, the weaker the noise. The maximum noise and the minimum noise are divided into several levels, each of which is called a level. The number of gears divided into is called the squelch level. Users can choose according to the actual situation.
11.ctcss cdcss function.
Use this feature to avoid receiving irrelevant calls.
12.2-tone DTMF call function.
Use 2-tone or DTMF signaling to select the appropriate intercom to call.
13.Reverse frequency
When using the reverse frequency function, the transmitting and receiving frequencies of the radio are interchanged, and the signaling is also interchanged.
14.Talk around
When using the off-grid function, the transmitting frequency of the radio becomes the same as the receiving frequency; The transmit signaling is also converted to the same as the receive signaling.
15.Auto-transpond
When the radio receives a properly coded call, it sends a signal to the caller in response to the call.
16.Emergency alarm
Press the special alarm button, and the walkie-talkie will sound an alarm at maximum sound or send out a predetermined alarm code to other handsets or base stations.
17.Patrol Record
When the patrol officer arrives at the patrol point, the walkie-talkie will receive the query signal sent by the patrol registration device, and then automatically start the registration operation, and send its own identity code and other information to the patrol registration device for registration, indicating that a patrol officer has arrived at the place.
18.Keylock
Use this function to prevent misoperation of keys.
19.Battery indicator
Displays the battery level.
20.Lighting function (backlight).
It is used for operation at night or in dim conditions, and the LCD display and keys can be clearly read.
21.Cloning
This feature allows the data from one walkie-talkie to be copied to other walkie-talkies of the same model.
22.Modulation.
One or more parameters of the modulation signal are used to control the change of the parameters of the carrier, and according to the different control parameters, modulation can be divided into amplitude modulation, frequency modulation and phase modulation.
23.Audio.
Audio, which refers to the sound frequency of human speech, usually refers to the frequency band of 300Hz-3400Hz.
24.Carrier wave.
Carriers of useful signals such as voice, digital signals, and signaling, and high-frequency electromagnetic waves that are easy to transmit.
25.Channels and channel spacing.
Channel refers to the frequency value occupied by transmitting and receiving. The difference in frequency between adjacent channels is called the channel spacing. The specified channel spacing is 25 kHz (wideband kHz, 12.).5kHz (narrow band), etc.
26. 2-tone
2-tone, two-tone signaling, consists of two audio signals, a tone + b tone. Send a tone for a while, then B tone after a while. 2-tone signaling allows you to optionally call the corresponding intercom.
27. 5-tone
5-tone, 5-tone signaling, which functions the same as two-tone signaling, except that it consists of five frequencies.
28. ctcss
CTCSS (Continuous Tone Controlled Squelch System), commonly known as sub-audio, is a frequency that will be lower than the audio frequency (67Hz-250.).3Hz) is attached to the technology of transmitting together in the audio signal. Because its frequency range is below the standard audio, it is called sub-audio. When the walkie-talkie performs intermediate frequency demodulation on the received signal, the sub-audio signal is filtered and shaped, and input into the CPU, and compared with the CTCSS frequency set by the machine, so as to decide whether to turn on mute.
29. cdcss
CDCSS (Continuous Digital Controlled Squelch System) has the same function as CTCSS, except that it is digitally coded as a condition for whether mute is turned on.
30. dtmf
DTMF (Dual Tone Multi Frequency) is composed of high frequency group and low frequency group, and the high and low frequency group each contains 4 frequencies. A high-frequency signal and a low-frequency signal are superimposed to form a combined signal, representing a number. DTMF signaling has 16 codes. DTMF signaling can optionally call the corresponding intercom.
There are several factors to consider when buying a walkie-talkie:
Whether it's a grueling backcountry crossing or a casual skiing, horseback riding, or other activities, the walkie-talkie is the best way to keep your team connected. The particularity of field activities has put forward some special requirements for our purchase, which need to be considered as follows:
1 Power Supply. 2 Frequency compatibility.
3 Operability, waterproof and shockproof.
4 Power. 1) Power selection.
Commonly used walkie-talkie power supplies are: lithium battery rechargeable battery, nickel-metal hydride rechargeable battery, AA alkali battery. It is generally not possible to charge in the field, so the standby time and talk time of the walkie-talkie is a more important parameter, otherwise there is often a problem due to the insufficient power of the walkie-talkie when communication is most needed. Generally speaking, the power of walkie-talkies powered by lithium battery and nickel-metal hydride is relatively large, but the backup battery is a big problem; The power of the walkie-talkie with alkaline battery as the power supply is generally less than 2W, but it is still possible to carry dozens of No. 5 batteries up the hill.
2) Communication frequency.
The relationship between communication frequency and radio communication is as inseparable as the road and the car. There are two main types of walkie-talkies**: those brought back from abroad; Walkie-talkies for civilian people purchased in regular stores in China. Although they all communicate in the UHF frequency band, due to the difference between domestic radio frequency band management regulations and international standards, the communication frequency of these two types of walkie-talkies is also very different
Another point that should be noted is that because each of us is not a fixed team, there are bound to be different types of hand tables, in order to better use, it is recommended that you buy an adjustable hand table. This can greatly enhance the operability of the handpiece.
Since the brand of walkie-talkie is too right, I will not list them one by one, after all, everyone has everyone's appreciation angle and focus on use.
Select Q&A:
Q: Are there any rules for using walkie-talkie to talk?
A: In the amateur section, there are very strict communication regulations, and there will be special training when taking the license exam. In the license-exempt 409m, there are the following provisions:
The transmitting frequency shall not be changed without authorization, the transmitting power shall be increased (including the installation of additional RF power amplifiers), and the external antenna shall not be connected or other transmitting antennas shall be used without authorization;
Once harmful interference is discovered, the use shall be stopped immediately, and measures shall be taken to eliminate the interference before continuing to use;
The communication quality of the public walkie-talkie is not protected by the radio regulatory body, and it should withstand the interference that may be generated by other radio services in normal operation;
It is forbidden to use it in airports and aircraft;
It is forbidden to interconnect with public networks, public mobile communication networks and other telecommunication networks.
Q: What kind of walkie-talkie should I buy for hiking and mountain climbing?
A: First of all, you should have at least one national license-exempt walkie-talkie (409MHz, 0.).5W transmit power, 20 channels), the communication distance in the city is about 500 meters, and the suburbs can reach one to three kilometers, for entry-level use. Then, you can consider taking the license and using the amateur segment (430-440MHz, the mill green field frequency point is also in this range) hand and car wagons.
Q: Can I buy a model that takes into account both the 409m and the amateur segment in one step?
A: Yes, but don't buy those brands or models with unstable performance. After all, the first requirement for communication in outdoor sports is: reliability. In addition, these models may not pass the inspection of the committee.
q：0.5W 2W 4W, how much call distance does it correspond to?
A: There are many factors that determine the communication distance, and the height, antenna, and terrain all affect the communication distance more than the power, so there is no one-to-one correspondence between the power and the call distance. The design, process, and component quality of different brands also affect the power play.
Q: What are the consequences of using an amateur segment without a license (e.g. Mill Green Field)?
A: Technically, using amateur segments without sufficient knowledge can cause distractions to others without knowing it. Legally, you can have your equipment confiscated and you can be fined, with serious consequences (which you may not know about) and imprisonment for up to three years. If the *** law is violated at the same time, it is even more serious.
And in the amateur segment, if you call without a legitimate call sign, no one will bother you, because the licensed and unlicensed communication will have their license revoked.
Q: There are some parallel intercoms that are marked as FRS GMRS license-exempt frequency bands, can they be used in China?
A: FRS GMRS is a license-exempt frequency band in some foreign regions, but this frequency band (462-467MHz) has long been classified as other specialized uses in China. So if you launch at this frequency, you're already interfering with the legitimate use of others. Since we don't want others to interfere with our communications, we certainly shouldn't interfere with others' normal communications.
Q: What is dumb audio? What's the use?
A: In the amateur segment, this function is mainly used for communication with repeaters. At the license-free 409m, the dumb audio function is almost useless, and if your walkie-talkie has this function, be sure to set it to "0". Otherwise, there will be a situation where someone else receives you, and you can't hear someone else's signal, which is very unfavorable for rescue. This function was originally used in a noisy channel, the two parties can agree to use the same dumb audio, so that when the transmitter speaks, the machine will automatically add an audio to the radio wave, and the receiver will take out the signal with this agreed audio, and block other signals without the audio attached. The problem is that when there is no sound on your walkie-talkie, it doesn't mean that the channel is free, maybe someone else is connecting, and you can't hear it because of the dumb audio, and if you transmit at this time, it will interfere with other people's communication. That's why we jokingly call it a "selfish" function.
Q: In case of emergency, how to use the walkie-talkie to call for help?
A: The amateur segment should call the relay station and maritime SOS channel within 300km in the order of distance, and then operate according to the specification and will not be repeated. For 409m, the following steps should be followed:
Start by gathering some phone batteries to spare so that you have a backup battery when the walkie-talkie battery runs out. Retrofitting is very easy, just two metal wires are all you need. Only two walkie-talkies were left in the team when they were turned on, and all others were turned off to save batteries.
Find two team members with good physical strength and clear thinking, and bring two walkie-talkies to the highest point nearby (the higher the better, but pay attention to your own safety). A walkie-talkie is on channel 15 to listen (be sure to turn off the mute function!) The other is a circular call from channel 1 to channel 20: "sos sos here is xx xxx in a certain mountain emergency call for help, here is xx xxx in a certain mountain emergency call for help, please receive a signal to channel 15 to reply to me, please receive a signal to channel 15 to reply to me", a round of calls is completed after 10 minutes and then the next round of calls. If there is no reply after an hour, you can consider moving to a higher and more open position, and you should keep listening to channel 15 during the move. On the top of the hill with no shelter on all sides, 0It is possible for the signal of the 5W walkie-talkie to be transmitted for hundreds of kilometers.
Q: What should I do if I receive a distress signal on the intercom?
A: In order of importance: first, ensure the safety of yourself and the team; second, inform the whole team to abandon the original plan and save people with the sole goal; Third, establish contact with the outside world, send out the distress signal, and act as a communication bridge between the help-seeker and the outside world; Fourth, rescue within our capabilities. The third point is very important, don't take any action if you haven't already sent the distress signal to the outside world.
Q: Are the headphones easy to use? Is the VOX feature useful?
A: The headset is not suitable for sports with a large limb amplitude, which is easy to cause the headset to fall off and you don't know it, so you will delay the contact. Headphones can be used for hands-free sports, such as road biking and paragliding, but be sure to get into the Xi habit of checking headphones at all times. If you must use headphones, it is best to let friends who understand electronics modify the headphone jack so that the headphones and speakers can sound at the same time, reducing the possibility of not hearing the call due to the headset falling off.
The VOX function can judge the intensity of the surrounding sound by the microphone level, and automatically emit when you speak, without having to press the transmit button with your hand. This function is very unreliable in noisy, multi-person environments, resulting in frequent launch states that you don't know about it, which costs electricity and disturbs others. Therefore, it is not advisable to use the VOX feature.
(Text**China Radio Management**, the original title is "The Most Complete Walkie-Talkie Basic Knowledge and Equipment Recommendation in History").