How far does the walkie-talkie usually work? But how many people talk to each other?

How far is the communication distance of the radio?

The communication distance of conventional walkie-talkies is generally 3~5 kilometers, but it will be relatively short when there are tall buildings or mountains blocking it. With network support, intercom can reach tens of kilometers.

What is a walkie-talkie

A walkie-talkie is a device that can talk to a person or a group of people by pressing keys.

Who uses the radio?

Today, walkie-talkies are used in many different occasions and businesses: transportation of hotels and restaurants, manufacturing, petroleum, mining, government agencies, tourism, conference services, event organization and security.

Who will benefit from two-way radio?

Employees in many companies have to move around in their work. They can use walkie-talkies to realize its benefits:

If you need to contact someone who is constantly moving or absent, you need to repeat a message to the other person. Most of the communication in your company is within the company, so you need to respond quickly in case of emergency. You have some vehicles or people moving in a fixed area, you manage some equipment or several buildings, and your delivery and production plans often change.

How to improve the efficiency of radio interphone?

The walkie-talkie is a necessary tool for one person to contact a group of people in the company. With just one phone call, this person can talk to everyone in the group, no matter where they are. The walkie-talkie can also be connected to a local phone.

How to save the cost of radio interphone?

Unlike mobile phones, walkie-talkies don't have to be charged according to the call time. Comparing the cost of mobile phones and two-way walkie-talkies, users will find that walkie-talkies are more economical and practical.

With the popularity of mobile phones today, why do people choose to use wireless walkie-talkies?

This is because the walkie-talkie has many unique features compared with the mobile phone: the walkie-talkie is not restricted by the network, and it can make users communicate easily where the network is not covered; The walkie-talkie provides one-to-one and one-to-many calls, which is simple to operate and more free to communicate, especially in the case of emergency dispatch and collective cooperation. These characteristics are very important; Call charges are low.

How far is the communication distance of the radio?

Can mass consumers buy walkie-talkies?

Mass consumers can also buy walkie-talkies

However, before buying and using walkie-talkies, you must apply to the local radio management committee (hereinafter referred to as "the 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.

Is there a charge for talking on the intercom?

No matter how often you use regular walkie-talkies, there is no charge, and each walkie-talkie only needs to pay a frequency occupation fee of tens of yuan every year. If you use the public walkie-talkie, you don't need to pay any fees.

Why is there a frequency limit when using walkie-talkies?

In order to ensure that most users' calls are not disturbed and make rational use of frequency resources, the National Radio Regulatory Commission has divided the use of frequencies and stipulated that different industries should use corresponding frequency ranges. When purchasing walkie-talkies, users should apply to the local radio management committee for frequency points.

Q: When buying and using radios, you often encounter many Chinese and English terms. What do they mean?

Monitor (monitor)

A monitoring method for receiving weak signals. By pressing the special key to forcibly connect the receiving signal channel, the operator can distinguish the weak sound in the speaker with his ears and achieve the purpose of listening.

Scan (scan)

A listening mode for listening to all channels.

By pressing the dedicated key, the receiving circuit can receive the signals in the channels one by one in a certain order for a period of time. If the receiving time of each channel is 100ms, ten channels can be scanned every second, that is, the scanning speed is10 ch/s.

Priority channel scanning function (priority channel scanning)

In the scanning process, the set priority channels are preferentially scanned.

Delete/Add Scan Channels (Delete/Add Scan Channels)

Delete or add channels in the scan list.

Voice control (VOX)

When this function is activated, the transmission operation can be started directly by voice without pressing PTT key.

Start the time limit function (TOT: timeout timer)

This function is used to limit the user's overtime transmission on a channel, and at the same time avoid the damage to the walkie-talkie caused by long-term transmission.

Battery saving function

In order to save electricity and prolong standby time, the walkie-talkie will save electricity without receiving transmission and pressing the button for a period of time, and will be turned off and on for a period of time. The switching duration ratio is about 1: 4. When receiving the signal or operating the key, the interphone immediately exits the power-saving state and enters the normal state.

High/low power selection function (high/low power)

This function allows users to choose high power or low power according to the actual situation.

Busy channel locking function.

When using this function, users are prohibited from transmitting signals on busy channels.

Quiet level

The intensity of noise in the received signal corresponds to the intensity of the signal, and the stronger the signal, the weaker the noise. The maximum noise and the minimum noise are divided into several levels, and each level is called the first level. The number of divided files is called squelch series. Users can choose according to the actual situation.

CTCSS/CDCSS function

Use this function to avoid receiving irrelevant calls.

Dual tone/dual tone multi-frequency selective calling function

Use dual tone or DTMF signal to select and call the corresponding interphone.

Reverse frequency function (reverse frequency)

When using the scrambling function, the transmitting frequency and receiving frequency of interphone will be interchanged, and the set signaling will also be interchanged.

Intercom function

When offline function is used, the transmitting frequency of interphone becomes the same as the receiving frequency; The transmission signaling is also changed to be the same as the reception signaling.

Automatic response function (automatic transnational)

When the intercom receives a correctly coded call, it will send a signal to the caller to respond to the call.

Emergency alert (emergency alert)

Press the special alarm key, and the intercom will give an alarm sound at the maximum sound or send a predetermined alarm code to other mobile phones or base stations.

Patrol record

When the patrol personnel arrive at the patrol point, the walkie-talkie will receive the inquiry signal sent by the patrol register, and then automatically start the registration operation, and send its own identity code and other information to the patrol register for registration, indicating that the patrol personnel have arrived there.

Key lock function (key lock)

Use this function to prevent key misoperation.

Battery indicator

Displays the battery charge.

Lighting function (backlight)

Used for operation at night or in dim light, with clear LCD screen and buttons.

Copy function (cloning)

This function allows the data in one walkie-talkie to be copied to other walkie-talkies of the same model.

Adjustment; adjust

One or several parameters of the modulation signal are used to control the change of carrier parameters. According to different control parameters, modulation can be divided into amplitude modulation, frequency modulation and phase modulation.

audio frequency

Audio refers to the frequency of human voice, usually refers to the frequency band of 300Hz-3400Hz.

carrier wave

Voice, digital signals, signaling and other useful signal carriers are easy to transmit high-frequency electromagnetic waves.

Channel and channel spacing

Channel refers to the frequency value occupied when transmitting and receiving. The frequency difference between adjacent channels is called channel interval. The specified channel intervals are 25KHz (broadband), 20KHz, 12.5KHz (narrowband), etc.

Two tones

Two-tone, two-tone signaling, consisting of two audio signals, A+B. Start one

Tune it for a while, then interval for a while, and then send a b key. With dual tone signal, you can choose to call the corresponding interphone.

five notes of the ancient Chinese pentatonic scale

5-tone, 5-tone signaling has the same function as dual-tone signaling, except that it consists of five frequencies.

CTCSS

Continuous tone control squelch system,

Continuous voice control squelch system, commonly known as sub-audio, is a technology that attaches frequencies lower than audio (67Hz-250.3Hz) to audio signals and transmits them together. Because its frequency range is lower than the standard audio, it is called secondary audio. After the interphone demodulates the received intermediate frequency signal, it filters and shapes the secondary audio signal, and then inputs it into the CPU, and compares it with the CTCSS frequency set by this machine, so as to decide whether to turn on the mute.

CDCSS

Continuous digital control squelch

System), a continuous digital control mute system, has the same function as CTCSS, except that digital coding is used as the condition of whether to turn on mute.

dual-tone multifrequency

Frequency), dual-tone multi-frequency, consists of a high-frequency group and a low-frequency group, and each high-frequency group contains four frequencies. A high frequency signal and a low frequency signal are superimposed to form a combined signal, which represents a number. DTMF signaling has 16 codes. Using DTMF signaling, you can choose to call the corresponding interphone.

Q: How to build a network?

Networking purpose

Expand the communication coverage of walkie-talkies and extend the communication distance. The open space can reach 10-20km (handheld walkie-talkie) or even 30-50km (car walkie-talkie). The building can cover heavily shielded areas, such as basements, underground parking lots and fire exits, which are often called dead ends.

Networking program

The networking frequency shall be reported to the local radio management committee.

Networking principle

The single communication distance of walkie-talkie is limited, which can reach as far as 8- 10 km in the open area and only 3-5 km in the general urban area. Due to the shielding effect, the interior of the building can only cover the above-ground part. Networking is the use of relay stations (also known as base stations or turntables) to automatically receive signals transmitted by walkie-talkies and amplify and forward them, thus effectively expanding the communication range of walkie-talkies.

Network cost

Depending on the specific environment and conditions, as well as the equipment purchased, it ranges from 1 10,000 yuan to 20,000 yuan, and generally ranges from 700,000 yuan to110,000 yuan.

Q: How are the telecom frequencies and bands named?

Band number Symbol Metric abbreviation of metric segmented frequency band corresponding to frequency band within frequency range (excluding lower limit and upper limit).

-1ELF extremely low frequency 0.03-0.3 Hz gigawave B.Gm

00.3-3 Hz 100 MHz wave B.hMm

13-30 Hz ten megahertz wave

230-300 Hz MHz wave

3ULF ultra-low frequency 300-3000 Hz 100 km wave B.hkm

4LF VLF 3-30 kHz 10km wave B.Mam

5LF low frequency 30-300 kHz km wave B.km

6MF intermediate frequency 300-3000 kHz 100m wave B.hm

7HF high frequency 3-30 MHz 10m wave B.dam

8 VHF 30-300 MHz meter wave

9UHF UHF 300-3000 MHz decimeter wave B.dm

10SHF UHF 3-30 GHz centimeter wave B.cm