Don’t listen to the merchants’ lies: WiFi signals can’t actually penetrate walls

With the continuous iteration of WiFi technology, high-speed wireless networks have become another basic need for people at home, in addition to water and electricity. This has also led to a series of problems surrounding the purchase of home routers, among which "is the signal strong?" is the most concerned issue for most consumers. Many businesses have seized on this psychology of consumers and used words such as "super high power" and "wall-penetrating king" in their publicity to attract users to buy, but in fact such rhetoric is suspected of misleading consumers, because WiFi signals cannot penetrate walls at all.

Some friends may say that since the signal strength of the router is related to the power, why not just use high power to send it online? Unfortunately, this is not feasible in our country. Our country stipulates that the maximum transmission power of wireless routers on the market cannot exceed 100mW, which is 0.1W. This is also for the health of users.

From this perspective, the so-called "high power" advertised by merchants is actually self-defeating. After all, the maximum power limit is there, and everyone's level is actually about the same.

Since this approach doesn't work, how can we effectively enhance WiFi signals? Before clarifying this issue, let us first review the characteristics of WiFi signals during transmission.

The antennas used in the routers in our homes are all omnidirectional antennas, and the signals are uniformly radiated 360° horizontally. If the router is regarded as a whole, then the signal is radiated roughly like this.

The advantage of this is that the WiFi signal can evenly cover all directions, but correspondingly, its signal strength is not as good as that of a directional antenna. However, considering the home scenario, this design is also very reasonable. In actual propagation, WiFi signals (essentially electromagnetic waves) are reflected, refracted, diffracted, diffusely reflected, and penetrated after encountering different obstacles. Among them, the effect of refraction is the smallest and can be ignored, and the effect of penetration is the greatest, especially the cement walls and brick walls in the home, which can directly attenuate the WiFi signal strength of the 2.4G band to one thousandth, not to mention the 5G band with worse penetration. One more wooden door and one more corner will greatly reduce its signal strength.

This is why I told you at the beginning that "WiFi signals cannot penetrate walls at all". After all, a signal attenuated to one thousandth is no different from being disconnected. Therefore, the propagation of WiFi signals in the home mainly relies on reflection, diffraction, diffuse reflection, etc. After all, our rooms cannot use solid iron or stone doors, so the router placed in the living room can always find some gaps to transmit the signal to the bedroom.

Some users like to put the router and optical modem together in the weak-current box for aesthetic reasons, which is a very wrong behavior. You should know that metal obstacles have a huge impact on WiFi signals, which can easily reduce the signal strength to one ten-thousandth, which is why mobile phones still have no signal in elevators even in 2022. So don't underestimate the thin metal door of the weak-current box, it is simply a nightmare for WiFi signals.

Therefore, when purchasing a router, don't believe in words like "wall-penetrating king" or "wall-penetrating treasure". Pay more attention to the configuration, performance and interface of the router itself. Don't be greedy for cheapness. You get what you pay for.

For users who are not planning to upgrade their routers for the time being, I suggest starting with the placement and angle to enhance the WiFi signal. First, choose an open place, as high as possible above surrounding objects to avoid obstruction, so that the WiFi signal can radiate as much as possible. Be careful to avoid microwave ovens, Bluetooth speakers, wireless keyboards and mice, etc. to avoid interference.

Then there is the router's antenna. Although the antennas of routers with external antennas can be rotated and adjusted, in fact, due to the signal direction mentioned above, these antennas have the best signal when they are vertical.

As shown in the picture above, pointing the router antenna towards you will not enhance the signal, but will make you point it at the weakest part of the signal coverage. Therefore, our router only needs to stand up each antenna as shown on the manufacturer's packaging.

For those who have the budget to upgrade their routers, with current technology, a single router cannot provide full signal coverage throughout the house, especially in rooms with complex layouts and large rooms over 100 square meters. Every wall and every corner will cause a significant attenuation of the signal. Therefore, if you want to enhance the signal in rooms far from the router, purchasing multiple routers that support Mesh technology for networking is undoubtedly the most effective solution. It should be noted that the Mesh technology of each brand can only be matched with other products of the brand to achieve the best effect, and different brands are not interoperable.