Internet speed often depends less on the provider's plan and more on the quality of the wireless connection inside the room. When videos load slowly or online games lag, users immediately blame the provider, although the problem may simply be due to signal attenuation. WiFi signal strength — this is a key parameter that determines how confidently your devices will stay online at a distance.
Understanding how this indicator is measured and what values are considered normal will allow you to properly position your router or select the correct channel for operation. In this article, we'll explore the physical fundamentals of wireless communication, learn how to read operating system specifications, and use specialized software for accurate diagnostics.
The impact of physical barriers and transmitter settings on the final network performance should not be underestimated. dBm (decibels per milliwatt) is a unit you'll need to get to know to objectively assess the situation in your apartment or office. Let's figure out where this data is hidden and how to interpret it.
Physical principles and units of power measurement
Before moving on to practical measurements, it's important to understand the quantities we're dealing with. Unlike wired networks, where cable bandwidth is important, in wireless networks, the transmitter's radiated power is critical. This power is measured in milliwatts (mW), but you'll almost never see a direct power value in technical specifications or analysis software.
Instead of the usual watts, a logarithmic scale is used dBmThis is done to make it easier to work with a huge range of values, as the signal weakens hundreds and thousands of times when passing through walls. The dBm scale is negative: the closer the value is to zero, the stronger the signal. For example, -30 dBm is an excellent signal, while -90 dBm is a barely audible whisper before the connection drops.
⚠️ Caution: Don't confuse transmit power (Tx Power) with receive sensitivity (Rx Sensitivity). Your router may be very loud, but if your smartphone has a weak receiver, you won't have a stable connection.
There is also a concept EIRP (equivalent radiated power), which takes into account not only the power of the router chip itself but also the antenna gain. This parameter is often regulated by law in various countries. In Russia, the maximum permissible radiated power in the 2.4 GHz band is strictly regulated, and equipment manufacturers are required to hardcode these restrictions into the firmware of their devices.
Why is power not infinite?
Increasing transmitter power beyond certain limits not only violates the law, but also creates a "mess" of interference, reducing the overall network throughput for all users within a radius of several kilometers.
Checking signal strength on a Windows computer
The Windows operating system provides built-in diagnostic tools, hidden from the average user. The easiest way to view the current connection status is to use the command line. This method doesn't require installing third-party software and provides instant results in a clear numerical format.
Open a command prompt (cmd) as an administrator or a standard user and enter the command netsh wlan show interfacesIn the list that appears, find the "Signal" line. It will display the value as a percentage. However, percentages are a rough approximation. For precise dBm data, it's best to use PowerShell.
In PowerShell, the command is a little more complex, but it provides more technically accurate data. Enter:
(netsh wlan show interfaces) -match'^\s+Signal' -replace'^\s+Signal\s+:\s+',''If you have an English-language version of the system, replace the word "Signal" with "Signal." You'll get a percentage value that can be roughly converted to dBm, although the exact formula depends on the network card driver. For a more detailed analysis, it's best to use specialized utilities, which we'll discuss below.
☑️ WiFi diagnostics on Windows
WiFi Network Analysis on Android and iOS Smartphones
Mobile devices are closest to the internet connection, so smartphone measurements are often the most relevant for assessing the real user experience. On Android, the situation is much simpler: the system is designed from the ground up for engineers and testers.
In the settings of most Android smartphones (Wi-Fi section), you can find technical information about the current connection. By tapping the network name or the gear icon, you'll see the "Signal Strength" or "RSSI" parameter, expressed in dBm. This is the signal strength we're looking for. On iOS, things are more complicated due to the closed ecosystem.
Apple doesn't provide iPhone owners with direct access to raw signal strength data in the standard settings interface. The only legal way to obtain detailed information is through Apple's AirPort Utility, but this requires a connection via macOS. However, there are third-party scanner apps that display signal strength as a graph or a number, which is sufficient for home diagnostics.
A measurement taken on a flagship model with external antennas might show -60 dBm, while a budget model at the same point would show -75 dBm. This doesn't mean the router has changed its power; the devices simply have different "ears."
Using specialized scanning programs
For in-depth analysis of the radio frequency spectrum and precise signal strength measurements, specialized applications are best suited. They can generate graphs, show channel noise levels, and, most importantly, display precise values. RSSI (Received Signal Strength Indicator) in dBm for all visible networks.
One of the most popular utilities for Windows is inSSIDer or WiFi Analyzer (available in the Microsoft Store). These programs visualize the "air" and show how your router compares to your neighbors' routers. You'll see the values you're looking for in the "Signal" or "Power" column. Similar apps are also available for Android, for example, WiFi Analyzer (open-source) or Network Analyzer.
Using such programs allows you not only to check your current signal strength but also to understand why it's declining. For example, you might notice that the 2.4 GHz signal drops sharply when you turn on your microwave, or that your neighbor's router is jamming yours on one channel.
| Signal level (dBm) | Connection quality | Description | Possible actions |
|---|---|---|---|
| -30.. -50 | Excellent | Ideal speed, located close to the router | No action required |
| -51.. -65 | Good | Stable operation, 4K streaming possible | Optimal range for work |
| -66.. -75 | Average | Rare breaks are possible, speed decreases | Move the router or change the channel |
| -76.. -85 | Bad | Only web surfing, video is slow | A repeater or mesh system is needed. |
| -86.. -95 | Critical | Constant disconnections, barely picks up the network | Signal amplification is a must |
Setting the transmitter power in the router interface
Many users don't realize that their router's transmit power can be controlled programmatically. By default, most models (TP-Link, Asus, Keenetic, MikroTik) are set to "Auto" or "100%." However, in an apartment building, full power isn't always a good option.
Log into your router's web interface (usually at 192.168.0.1 or 192.168.1.1). Find the "Wireless" -> "Professional" or "Advanced" section. There may be a "Tx Power" slider. The available options are often: High, Middle, or Low.
Reducing the power can help if you have a small apartment and your router is located in a central location. By reducing the power, you'll reduce the noise level for yourself and your neighbors, which can sometimes paradoxically improve connection stability by eliminating echo and signal reflections from walls.
⚠️ Note: Settings interfaces may vary depending on the firmware version. If you don't see the power slider, the manufacturer may have blocked this feature for your region due to local regulations.
In some cases, especially on older models or firmware versions for specific regions (such as the US), more precise decibel settings are available. However, for 95% of home users, selecting "High" mode is sufficient if the router is located far away, or "Middle" if it's nearby.
Factors Affecting Actual Signal Strength
Even if your router is delivering maximum power, the actual signal in your room may differ significantly from what you expect. Radio waves are a physical object that interacts with the environment. Understanding these factors will help you place your equipment correctly.
The first and foremost enemies of WiFi are metal and water. Reinforcement in concrete walls, foil insulation, mirrors, aquariums, and even houseplants with a lot of moisture can shield or absorb the signal. A microwave oven operating at 2.4 GHz creates powerful interference, completely clogging the airwaves while cooking.
The second factor is the number of active clients. Signal strength — is one thing, but channel bandwidth is another. If 20 devices are connected to a router, each downloading something, even with a full signal strength (-30 dBm), the internet will be slow due to a lack of time slots in the router's processor.
Frequency range is also important to consider. A 5 GHz signal has a shorter wavelength than a 2.4 GHz signal. This means it attenuates faster when passing through walls, but provides much higher speeds over short distances. Therefore, in an adjacent room, through two walls, a 5 GHz signal might show -80 dBm, while a 2.4 GHz signal will maintain a robust -60 dBm.
Faraday effect
If you place the router in a metal box or behind a foil shield, the signal will completely disappear. This demonstrates how metal structures in the walls of modern homes can block WiFi.
Frequently Asked Questions (FAQ)
Is it possible to increase the power of a WiFi router beyond the factory setting?
Technically, this is only possible by flashing the device to alternative firmware (such as OpenWrt or DD-WRT) and changing the regional settings (for example, to the US or Japan, where restrictions are higher). However, this may lead to chip overheating, unstable operation, and violation of the laws of your country.
Why does my phone show 100% signal, but the internet doesn't work?
The signal percentage only indicates the quality of the connection between the phone and the router, not whether the router is accessible to the global network. The issue could be with the provider, with the DNS settings, or the router may simply be frozen and require a reboot, while the radio module remains active.
Does the number of antennas affect signal strength?
The number of antennas doesn't directly increase the transmit power (it's limited by the chip), but it improves reception quality and connection stability thanks to MIMO technology. Antennas work for both reception and transmission, helping the device lock onto a signal in challenging conditions.
How often should I check my signal strength?
A single test during the initial network setup is sufficient. A repeat test is required if you've changed the apartment layout, purchased new metal furniture, moved, or noticed a sudden drop in internet speed without changing your plan.