How to use cans to enhance WiFi signals

Notebook Experiment

Recently, a post on the Maopu forum titled "Homemade WiFi signal amplifier made from cans~~Tech geeks save the world!" was quickly spread. The post said that after a wireless router is equipped with a copycat signal amplifier made from a can, the signal strength will be enhanced.

"Technical geeks can't afford it!" "Powerful netizens are educated!" There are many people posting comments, but most netizens are still skeptical. Yesterday, our curiosity laboratory conducted this experiment, and the experiment proved that after the router was covered with a can, the signal of both the laptop and the mobile phone was strengthened.

Xiaoxiang Morning News reporter Wen Naifei reports from Changsha

Experimental location: A residential area near Gaoqiao Market

Experiment time: afternoon of November 9, 2011

Experimenter: Mr. Yang, a technical expert

Experimental tools: one or two cans, a knife, a pair of scissors, a wireless router, a mobile phone with WiFi signal, and a laptop with wireless network

How cans become legendary signal amplifiers

Step 1: Select an aluminum can, rinse it clean, and remove the ring on the can;

Step 2: Cut off the entire bottom of the can. The aluminum sheet is very sharp and can easily hurt your hands, so be careful when operating;

Step 3: Cut a part of the can, leaving about 1cm uncut, and choose the 1cm position close to the drinking hole of the can;

Step 4: Draw a vertical line opposite the uncut part, and cut the bottle into two parts along this vertical line;

Step 5: Expand the bottle into a fan shape, turn the can upside down, and insert the wireless router antenna into the drinking hole of the can;

Step 6: If the router's antenna is longer than the can, it is best to make another one according to the above steps and put it outside the first can.

[Notebook test]

Experimental environment: Mr. Yang walked into room A with his laptop. There was a room B with closed doors and windows between the room and the wireless router, which was about 7 meters long. In other words, the computer and the wireless router were separated by 2 walls and a 7-meter-long space.

Experiment 1: Before putting on the can, the laptop's wireless signal was 4 bars.

Experiment 2: Put a can on the wireless router. In less than 5 seconds, the signal strength suddenly becomes 5 bars.

Experimental results: After the router was equipped with a homemade can signal amplifier, the signal was significantly enhanced although it was separated by two walls.

[Mobile phone test]

Before the experiment, Mr. Yang downloaded a WiFi signal detection software on his mobile phone to accurately test the signal strength.

Experimental environment: Mr. Yang placed his mobile phone facing the wireless router, 3 meters away.

Experiment 1: Without the can, the signal strength is -58dBm

Experiment 2: Put on the can, the signal strength is -44dBm

Experimental results: At close range, the signal on the mobile phone was enhanced by putting on the can.

Note: Instructions for use of this WiFi signal detection software: It is used to detect the WiFi signal strength of the mobile phone. The unit of strength is dBm (decibel milliwatt), which is generally expressed as a negative number. The normal signal range is from -110dBm (bad) to -50dBm (good).

[Explanation]

The inner surface of a can can reflect radio waves

Why can the fake signal amplifier in cans amplify the signal?

"In theory, it is feasible," said Dong Jian, a doctoral student in information and communication engineering at the School of Information Science and Engineering of Central South University. The principle of the experiment is that the inner surface of the can reflects radio waves, which enhances the antenna's ability to transmit and receive signals. "It is equivalent to concentrating the scattered signals in one direction. But the back of the can correspondingly weakens some of the signals."

How should the cans be placed to maximize the signal? Dong Jian said that there is indeed an "optimal position". "Based on the curved shape of the can, a focus is determined. This focus is where the antenna is placed, but it takes some effort to calculate the position of the focus."