If you find that your newly purchased 2.4GHz or 5.8GHz device does not provide the wireless coverage that you expected, it does not necessarily mean that there is a problem with the device, or that you have placed the device in the wrong location. More than 90% of the reason is that you did not configure the device.

Connect a suitable antenna; even if your WiFi client can access the Internet through your home wireless router, have you checked the actual wireless signal strength, if the signal-to-noise ratio (SNR) is too low, the wireless transmission speed cannot reach 54Mbps or more High speed, of course, wireless interference will also affect the transmission speed, but even the basic wireless signal is not good, so don’t expect high-speed Internet access.

WIFI Antenna

WIFI Antenna

So which type of antenna should we choose?
This cannot be explained clearly in a few words. Choosing a suitable antenna is actually a science. We must start with understanding the basic knowledge of the antenna. The following article will introduce the principle of the antenna and some antenna parameters. I believe it can help you select and install the appropriate antenna, thereby enhancing the effective coverage and performance of the wireless system.

The antenna is a passive body, that is, it does not need to provide power or other energy. It is also not a power amplifier and will not amplify the input wireless signal. On the contrary, due to the signal attenuation caused by the feeder and the connector, the wireless energy emitted will be greater than that of the input The energy of the antenna contact is low.

In fact, the antenna only plays the role of a directional amplifier, so that the transmitting and receiving energy is concentrated in a specific area of ​​the space. The only purpose of the antenna is to change the energy distribution area to the place where it is needed. In some places without wireless equipment, or over-distributing energy to a certain area, it is wasteful. According to the law of invariance of energy, increasing the energy distributed in one direction means reducing the energy in other areas.

An omnidirectional antenna, that is, it shows uniform radiation in 360° on the horizontal pattern, which is commonly referred to as non-directional, and shows a beam with a certain width on the vertical pattern.

In general, the smaller the lobe width, The greater the gain. The omnidirectional antenna is generally used in the mobile communication system with the station type of the suburban district system, and the coverage is large.

Directional antennas show a certain angular range of radiation on the horizontal pattern, which is usually called directional, and show a beam with a certain width on the vertical pattern. Like omnidirectional antennas, the smaller the lobe width , The greater the gain.

Omnidirectional and Directional Antenna

Omnidirectional and Directional Antenna

Directional antennas are generally used in urban cell-based stations in mobile communication systems, with small coverage, high user density, and high frequency utilization. Different types of base stations can be established according to the requirements of the networking, and different types of base stations can choose different types of antennas according to their needs. The selection is based on the above technical parameters.

For example, an omnidirectional station uses an omnidirectional antenna with basically the same gain in each horizontal direction, while a directional station uses a directional antenna with a significant change in the horizontal gain.

Omnidirectional antenna

Omnidirectional antenna

Generally, an antenna with a horizontal beam width B of 65° is selected in the urban area, and an antenna with a horizontal beam width B of 65°, 90° or 120° can be selected in the suburbs (depending on the station configuration and local geographic environment), and in the countryside It is the most economical to choose an omnidirectional antenna that can achieve large-scale coverage.

Specifically, you have to say which one is good, and this one is not easy to determine, depending on your use case.

Is it faster with 2 antennas or 4 antennas? I believe there must be many friends who are swaying around because of the “antenna” problem when choosing a router, and they can’t make up their minds. Let’s take Huawei Router A1 as an example, let’s talk about those things between the chat line and the router!

 

Which is faster, internal antenna or external antenna?

To answer this question, you might as well take a look at the status quo and differences between external antennas and internal antennas: external antennas appeared earlier than internal antennas. Early wireless router antennas were basically external; in recent years, internal antennas It has become popular, and all mainstream manufacturers have introduced routers with built-in antennas. Due to the built-in antenna, the appearance of the router is more fashionable and concise, and it is more in line with the aesthetics of modern people.

 

The angle of the external antenna can be adjusted, and the different placement of the antenna has a greater impact on the performance and network speed of the router. If the angle is not placed properly, it will affect the user’s Internet experience; and the built-in antenna is designed to be optimized by default. No need for user adjustment.

 

External antennas are easier to implement. If you encounter complex scenarios and environments, there are more solutions; built-in antennas must take into account the optimal space and antenna performance, which is relatively difficult to implement and requires manufacturers to have higher capabilities.

 

In fact, the internal and external antennas are just a solution to the router antenna design. Under current technical conditions, the router will not simply differ due to the internal or external antennas and the signal. Therefore, whether the external antenna or the internal antenna should not be the primary consideration when choosing a router.

 

What is the relationship between the wireless protocol and the number of antennas?

When choosing a router, users should pay more attention to the wireless protocol and the number of antennas, because they directly determine the Wi-Fi transmission rate.

 

Through official promotional materials, you can basically calculate the Wi-Fi rate of Huawei Router A1.

11ac 2*2 in the data indicates that it supports 802.11ac and 2 antennas, so the Wi-Fi rate is 433.3*2=866.6. 11n 2*2 indicates that it supports 802.11n and 2 antennas, so the Wi-Fi rate is 150*2 =300. The total of the two is 1167.6 (Gigabit), rounded to about 1200Mbps. The “Gigabit WiFi”, “Gigabit wireless router”, and “11AC technology” promoted by Huawei refer to this.

 

If you master the relationship between the wireless protocol and the number of antennas, you can easily avoid the various “pits” of the merchants when choosing a router in the future. For example, if a router claims to support Gigabit, it must support 11ac. If it does not support 11ac, it is definitely false propaganda! Another example is the number of router antennas (assuming 4), but only the highest rate of 300Mbps, which means that it actually only needs 2 11n antennas (2*150=300), and the extra two antennas are very likely It’s just a display, used to bluff people and increase their worth!

 

Should the router choose a product with a relatively high price and configuration?

Whether it is necessary to buy a higher-end wireless router depends on the cost performance of the product and the actual needs of users. The main consideration here is the home broadband and the size of the apartment. At present, the home broadband in most areas in China is 100M and below, and you can choose a dual-band route of 1200M. If the home broadband is greater than 100M, you need to choose dual Gigabit routers, such as Huawei Router A1 Enjoy Edition, can give full play to every megabit speed of ultra-100M fiber. Of course, if it is a large apartment with an area of ​​more than 120 square meters, multiple routers need to be used for intelligent networking to achieve seamless Wi-Fi coverage throughout the house.

 

Knowing yourself and the enemy can survive all battles. I believe that after understanding the relationship between routers and antennas, friends will be more calm and wise, less entangled and hesitate when buying routers in the future!

It has been almost a hundred years since the birth of the walkie-talkie, half a century before the invention of the mobile phone. But in the last century, mobile phones have evolved from the former “big brother” to today’s smart phones, and the walkie-talkie is still the same stupid, black and thick old one, and the antenna is still external. So is the external antenna of the walkie-talkie due to technical bottlenecks or deliberately?

 

The walkie-talkie uses an external antenna

First of all, walkie-talkie is a kind of radio communication equipment, and the radio that this equipment relies on has a very important indicator called “working frequency”. The working frequency of domestic mobile phones has national standards, and mobile phones generally operate between 900MHz and 1800MHz. Communicate on two frequencies, and the state stipulates that the working frequency of public walkie-talkies (ie, civilian walkie-talkies) is between 409 and 410 MHz.

 

Civil walkie-talkies have operating frequency restrictions

In order to transmit the radio signal as much energy as possible, the antenna needs to be designed to half the wavelength. The wavelength is equal to the speed of light divided by the frequency. The higher the frequency, the longer the wavelength. In other words, the wavelength of a mobile phone is more than half smaller than that of a walkie-talkie. However, when designing an antenna, it is impossible to design the antenna to be as long as the wavelength, but the longer the better.

 

Of course, mobile phone design cannot blindly pursue signal priority. After all, the current mobile phone is a necessity, and there is only one hand. The iPhone 4 started to make the appearance of the mobile phone beautiful, so many mobile phone manufacturers will put the mobile phone antenna into the body. The interior or the outer shell is integrated, which can please consumers more. After all, people are visual animals, and good-looking things can naturally sell better.

 

The stainless steel frame of the iPhone 4 is the phone antenna

In the early days of Big Brother’s era, the antenna was externally mounted. On the one hand, the priority of the mobile phone design was not as high as it is now. On the other hand, the mobile phone signal coverage at that time was not as good as it is now. The wireless signal used by the mobile cellular network works The frequency is not as high as it is now, and the signal enhancement that a larger antenna can bring is obvious, so the mobile phone antenna in the big brother era was external, or even retractable.

 

Early Mobile Phone with external antenna

The antenna design requirements of the walkie-talkie are similar to the design requirements of the early Mobile Phone. Since the use scene of the walkie-talkie does not have high requirements for the appearance of the walkie-talkie, the priority of the appearance design is lower than the priority of the antenna design. Moreover, the operating frequency of the walkie-talkie is much lower than that of the mobile phone, and a larger and longer antenna is needed to send the signal better.

Wireless bridges must be used in conjunction with antennas. There are two common wireless bridges and antennas, one is external, the other is internal. As the name suggests, the built-in antenna is installed inside the housing of the wireless bridge and is invisible on the surface. The built-in antenna is usually small and can be integrated with the bridge. The bridge and the antenna are integrated, which is convenient and compact and easy to carry. The disadvantage is that the transmission distance is relatively short. The transmission distance of the wireless bridge using the built-in antenna generally cannot exceed 10 kilometers. The external antennas come in several different shapes, which can be called different names according to different uses. For example, to distinguish by direction: there are directional antennas and omnidirectional antennas.

Directional antenna
The microwave signal is emitted at a fixed angle. Common angle antennas are 30 degrees, 60 degrees, 90 degrees, and 120 degrees. The angle of the directional antenna is limited, but because of this, the microwave signal transmitted through it can often be transmitted farther and more stable. The disadvantage is that the antenna must be aligned to achieve good microwave transmission. It is mostly used for point-to-point, point-to-multipoint, and relay link transmission.

Omnidirectional antenna
It transmits or receives microwave signals in all directions. Its microwave emission shape is a bit like an “apple”. There are fewer microwave signals directly above and below the omnidirectional antenna, which can be said to be black under the lamp. But its advantage is that it can perform wireless microwave transmission without aligning the angle. The disadvantage is that the transmission distance is short. It is mostly used for point-to-multipoint and relay link transmission.

In addition, the antennas are also divided into 2.4G and 5.8G frequencies. The wireless bridge of the corresponding frequency can only be used with antennas of the same frequency. For example, if a 2.4G wireless bridge is used, then 2.4G antennas must be used, and vice versa . Antennas can also be divided into single polarization and dual polarization antennas:

Single polarized antenna
It can only be used to transmit or receive microwave signals. Single-polarized antennas are mostly used at the transmitting or receiving end of point-to-point and point-to-multipoint wireless signals; while dual-polarized antennas are used to transmit and receive microwave signals at the same time, often used in wireless Relay relay of microwave signals.

Which antenna to use generally needs to be judged according to the site conditions, built-in, external, directional, omni-directional, single-polarized, dual-polarized, each has its own meaning, and users don’t need to worry too much when making a wireless plan. When determining which antenna to use, the user only needs to know the basic knowledge.