Every wireless network user sooner or later encounters a situation where the internet connection slows down or completely disappears in a distant room. We often blame the provider or outdated equipment, although the root of the problem lies in the physics of radio wave propagation. Understanding how it works radio signal, is the first step to building a stable home network.
There are many ways to evaluate connection quality, from the simple "look at the bars" on your smartphone to using professional software. Intuitive methods Often misleading, as operating systems hide the real picture, only showing a general overview of network availability. For accurate diagnostics, it's necessary to rely on numerical values and specialized tools.
In this article, we'll explore the meaning behind those mysterious numbers in the settings, why your neighbor's router might be interfering with your connection, and how to turn a chaotic connection into a reliable infrastructure. You'll learn how to read technical parameters and make informed decisions to improve your connection.
Units of measurement and signal levels
The main metric by which the received signal power is assessed is RSSI (Received Signal Strength Indicator). This is a relative indicator that may be displayed differently on different devices, but in the professional environment the de facto standard value has become dBm (decibel-milliwatt). These are the numbers you should pay attention to when making a diagnosis.
The paradoxical nature of the dBm scale is that all values are negative. The closer the number is to zero, the stronger the signal. For example, -40 dBm is ideal when standing practically point-blank to the router, while -90 dBm means the connection is about to drop. A difference of 3 dBm represents a doubling of the signal strength, making this scale very sensitive.
It is important to distinguish noise and a useful signal. Even if the reception level is high, but the noise floor is also high, the connection quality will be poor. The signal-to-noise ratio (SNR) is what really affects data transfer speed and ping in games.
⚠️ Note: Operating systems (Windows, Android, iOS) often round off or hide exact dBm values in the standard interface, displaying only graphical "bars." To obtain accurate data, you must use specialized software or the command line.
Below is a table to help interpret the obtained values:
| Value (dBm) | Connection quality | Description of the situation |
|---|---|---|
| -30 ... -50 | Excellent | Being in the same room as the router, maximum speed. |
| -50 ... -65 | Good | Stable streaming, video calls, and online gaming. |
| -65 ... -75 | Average | Occasional speed drops are possible, web surfing is problem-free. |
| -75 ... -85 | Bad | Video buffers, VoIP telephony works with delays. |
| -85 ... -95 | Critical | There is a connection, but data transfer is practically impossible, there are constant interruptions. |
Why are the values always negative?
The logarithmic dBm scale is measured from 1 milliwatt. Since the signal power at the receiving point is always less than 1 mW, the logarithm of this ratio yields a negative number. This is normal and does not indicate measurement error.
Built-in Windows and macOS tools
You don't always need to install third-party software to get basic information about your network's status. Operating systems provide basic tools that can answer questions about signal strength. In Windows, the fastest way is to use the command line.
Open the terminal (cmd) and enter the command netsh wlan show interfacesIn the list that appears, find the "Signal" line, which will display the power percentage. While this isn't an exact dBm, the conversion is simple: 100% is approximately -40 dBm, and 50% is about -75 dBm. This is enough for a quick estimate.
macOS users are more fortunate. By holding down the key Option By clicking the Wi-Fi icon in the menu bar, you'll see expanded information. It will show the RSSI parameter, which immediately displays the actual power in dBm, as well as the noise level and signal-to-noise ratio (Tx Rate).
However, built-in tools have limitations. They display the current connection status but don't provide a complete picture of the broadcast. You won't be able to see which channels are being used by your neighbors or how strong the signal is in another part of your apartment without physically going there.
Professional software for analysis
For in-depth diagnostics and detection of "dead zones," it's best to use specialized applications. They can create heat maps, analyze channel load, and display a signal attenuation graph in real time. an indispensable tool to set up Mesh systems or access points.
The most popular solution for Windows is Acrylic Wi-Fi Home or WiFi Analyzer (various versions from the Microsoft Store). These programs visualize the airwaves, showing signal "humps" from all available networks. You'll immediately see if your router is operating on a channel that's being jammed by five neighboring devices.
For Android, a great choice would be WiFi Analyzer (open-source) or NetSpotMobile apps are convenient because you can take them with you as you walk around your home ("walktest") and see how the schedule changes at different points. On iOS, the capabilities are limited by Apple's policies, but apps like AirPort Utility (with the scanner enabled in the settings) provide basic data.
Using such software allows you to identify not only weak points of coverage, but also problems with interferenceIt often happens that the signal is strong (-55 dBm), but the speed is low due to congestion of the 2.4 GHz band with microwaves and Bluetooth devices.
The influence of physical obstacles and interference
Signal strength directly depends on the materials it passes through. Radio waves in the 2.4 GHz and 5 GHz bands react differently to obstacles. Understanding this physics helps you place your router correctly without unnecessary expense.
- 🧱 Concrete and reinforcement: Wi-Fi's most serious enemy. A thick wall with a metal frame can reduce the signal by 20-30 dBm, turning a perfectly good connection into a dead end.
- 💧 Water: Aquariums, heating pipes, and even overwatered houseplants absorb radio waves. Avoid placing the router behind an aquarium or near the ceiling if there are pipes running there.
- 🪞 Mirrors and metal: Metal surfaces reflect the signal. This can be useful for redirecting the wave to the desired room, but more often creates echoes and dead zones.
- 📺 Household appliances: Microwave ovens operate at a frequency of 2.4 GHz and generate significant interference during operation. Refrigerators with metal doors also shield the signal.
The 5 GHz band has less penetration power but higher speed. If you need to penetrate two concrete walls, it's better to use 2.4 GHz or install a repeater. If you have a line of sight or are working through a single drywall partition, 5 GHz will provide stability.
⚠️ Note: Router interfaces and settings locations may vary depending on the model and firmware version. If you can't find a specific setting, consult the official documentation from your equipment manufacturer.
☑️ Checking the router's environment
Practical methods for measuring coverage
To get an objective picture, you need to take measurements at different points in the room. Don't rely on a single measurement in the center of the room. The procedure is simple: take a laptop or smartphone with the analyzer installed and slowly move around the apartment.
Start with the closest point to the router (1-2 meters). Record the maximum reading. Then move on to each room, including corners, the kitchen, and the bathroom. Record the readings or take screenshots. Pay particular attention to areas where you plan to work or play.
Pay attention to asymmetry Signal strength. Sometimes, the phone sees the router perfectly (-50 dBm), but the router "hears" the phone poorly due to the smartphone's lower transmitter power. This creates a situation where the network appears to be present, but packets are lost.
If you notice sudden signal drops in certain areas, try repositioning your antennas. Sometimes rotating the antennas 45 degrees or fanning them out (if you have multiple antennas) can significantly improve the signal in a specific area.
Troubleshooting and signal boosting
After running diagnostics, it becomes clear where the problem lies. If the signal is weak due to distance or walls, there are several solutions. The simplest is to move the router to a more central location, closer to the hallway or the center of the apartment.
If relocating the antennas is not possible, consider replacing them with more powerful ones (with a gain of 5-8 dBi). However, keep in mind that a powerful antenna only amplifies the signal in one direction, narrowing the antenna's radiation pattern. For multi-apartment buildings, this can even be detrimental due to interference.
In complex cases where one access point physically cannot cover the entire area, use Mesh systems or wired access points. Repeaters (amplifiers) are a compromise: they expand the coverage area, but often cut the speed in half because they operate in half-duplex mode.
Don't forget about software optimization either. Switching to a clear channel, updating your router firmware, and separating the 2.4/5 GHz bands into different SSIDs can improve stability without purchasing new hardware.
Why is my signal strong but my internet is slow?
A high signal strength (RSSI) only indicates the strength of the connection between your device and the router. Low speeds can be caused by high bandwidth usage from neighbors, issues with your ISP, data caps, or background downloads on other devices on the network.
Can foil or a can boost the signal?
Theoretically, a metal reflector behind the antenna can redirect the signal in the desired direction, increasing the power at a specific point. However, in practice, such "homemade" devices often create interference, overheat the router, and degrade the overall signal. It's better to buy a directional antenna.
Does weather affect indoor Wi-Fi?
Weather doesn't directly affect the signal inside an apartment. However, heavy rain or thunderstorms can affect the provider's equipment outside or the radio relay lines if the internet is transmitted over the air. Inside the home, humidity changes only slightly to affect signal attenuation.