Unstable internet performance is a familiar experience for every home network user. Speed drops, video buffers, and the connection keeps dropping out and coming back. Often, the cause isn't a problem with the ISP, but rather a weak connection. signal level, which is not taken into account when arranging equipment. Understanding how to measure this parameter is the first step to creating a stable and fast network.
There are many ways to obtain radio signal strength data, from built-in operating system tools to specialized software. In this article, we'll discuss how to interpret the obtained values and which tools provide the most accurate information. dBm — this is the unit of measurement that will become the main one for you in the diagnostic process.
Accurately measuring signal strength not only eliminates dead zones but also protects your network from unwanted intrusion. We'll cover methods for all popular platforms and explain why visual "bars" on a smartphone screen often lie. The ideal signal value is considered to be a range from -30 to -60 dBm; anything below -70 dBm is considered unstable.
Why the "stick" indicator is lying and what is dBm?
Users are accustomed to relying on a graphical signal display as a scale consisting of several divisions. The problem is that Android, iOS, and Windows operating systems use different algorithms to convert real power into these "bars." One device may show a full signal where another shows no signal.
For accurate diagnosis, it is necessary to use a logarithmic measurement scale, expressed in decibels relative to milliwatts (dBm). Since we're talking about the signal strength coming from the router to the receiver, the values are always negative. The closer the value is to zero, the stronger the signal, and vice versa.
The following table, which is universal for most network adapters, will help you understand the values:
| Value (dBm) | Signal quality | Job Description |
|---|---|---|
| -30 ... -50 | Excellent | Maximum speed, work near the router |
| -51 ... -60 | Good | Stable performance, suitable for streaming and gaming |
| -61 ... -70 | Average | Normal web surfing, speed drops possible |
| -71 ... -80 | Bad | Connection interruptions and low speed are possible |
| -81 ... -90 | Critical | There is a connection, but data transfer is almost impossible. |
It's important to understand that standard 4G or 5G modules may have different receiver sensitivities. Therefore, subjective internet performance cannot be relied upon. Only digital data provides an objective picture of the radio channel's condition.
⚠️ Warning: Values below -85 dBm often result in the device constantly reconnecting. If you see these values, using the network becomes virtually impossible without signal boosting.
Ignoring actual signal strength readings often leads to purchasing new equipment when the problem could have been solved by simply moving the router. Digital readings help make an informed decision about whether to install a repeater or replace the access point.
Checking signal strength on Windows (10 and 11)
The Windows operating system provides built-in tools for diagnosing wireless networks that don't require third-party software. The fastest way to obtain basic information is using the command line. This method is universal and works on most computers and laptops.
To run diagnostics, open a command prompt by typing cmd in the Start menu. In the window that opens, enter the command to display the interface status. This will allow you to see the current signal strength in numerical format, eliminating any graphical distortions in the interface.
netsh wlan show interfacesIn the resulting list, find the "Signal" line. The value will be displayed as a percentage, which is more informative than the "bars" but still doesn't provide a complete picture in dBm. For a more detailed analysis, you can use PowerShell with more complex commands, but for a quick check, this is sufficient.
If you need continuous monitoring or heat mapping of your apartment, you should turn to specialized utilities. Programs like Acrylic Wi-Fi Home or WiFi Analyzer (PC versions) provide graphs of signal changes over time.
Using third-party software on your PC is advisable if you plan to professionally configure your network or search for sources of interference. Built-in tools allow you to quickly verify that the adapter is actually "seeing" the network and receiving a sufficiently strong signal.
Diagnostics on Android and iOS smartphones
Mobile devices are the ideal tool for "walking" around your home to measure coverage. Android offers significantly more diagnostic options thanks to the open nature of the system. On iPhone, the situation is more complex due to Apple's limitations, but there are ways to do so.
On Android smartphones, the hidden engineering menu is often accessed by entering a code in the dialer or through Wi-Fi settings. Depending on the OS version and user interface (Samsung One UI, Xiaomi MIUI, stock Android), the path may vary. Typically, you need to go to Settings → Wi-Fi → Network Properties or click on the gear icon next to the network name.
Here you will see the parameter RSSI (Received Signal Strength Indicator), which is the desired value in dBm. For a more in-depth analysis, it is recommended to use scanner applications such as WiFi Analyzer or Network AnalyzerThey show not only the strength of your signal, but also how busy your neighbors' channels are.
⚠️ Note: On iOS, it's not possible to view the exact dBm value in the standard interface. This requires using diagnostic mode or special profiles, if supported by the enterprise version of the device.
If you are using an iPhone, you can use the app AirPort Utility from Apple. However, to see the hidden parameters, you need to activate a special mode in the app's settings (shake your phone or toggle the switch in iOS settings). After that, the RSSI will be displayed when scanning networks.
The advantage of mobile diagnostics is that it allows you to walk through every room and mark areas where the signal drops below critical levels. This helps determine the optimal location for installing a router or additional access point.
☑️ Checking the coverage in the house
Using the Command Line and Terminal for Pros
For system administrators and advanced users, the command line provides access to raw data that isn't filtered by the graphical interface. On Linux and macOS systems, the terminal is a powerful network diagnostic tool.
In macOS, which is a Unix-like system, you can use the utility airportHowever, it's hidden by default. To access it, you need to create a symbolic link or specify the full path to the executable file. This allows you to obtain detailed information about the current connection.
/System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport -IIn the command output, look for the line agrCtlRSSIThis is the signal level in dBm. You can also see the noise level here (agrCtlNoise), which allows us to calculate the signal-to-noise ratio (SNR), which is more important than the absolute signal power.
On Linux systems, depending on the distribution and wireless card drivers, you can use the commands iwconfig or iwlistFor example, the team iwconfig wlan0 (where wlan0 is the interface name) will output the line Link Quality And Signal level.
Using the terminal is especially useful when setting up Raspberry Pi-based servers or access points, which lack a graphical interface. Accurate data helps configure client disconnection thresholds or access point switching in roaming networks.
What is SNR and why is it important?
The signal-to-noise ratio (SNR) is the difference between the useful signal level and the noise level. Even a strong signal is useless if the surrounding noise level is even higher. An SNR above 20-25 dB is considered optimal.
Software analyzers and heat maps
When built-in tools aren't enough, specialized programs come to the rescue. They don't just display current values, but also generate graphs, help find free channels, and visualize coverage using heat maps.
Popular PC applications such as Acrylic Wi-Fi, NetSpot or Ekahau HeatMapper, allow you to create a floor plan and walk through it, marking measurement points. The result is a color-coded diagram, with areas of poor reception marked in red and areas of excellent reception marked in green.
This approach is indispensable in offices or large homes, where uniform coverage is essential. The software takes into account signal attenuation through walls and ceilings, helping plan equipment placement before purchasing.
Many modern routers (for example, Keenetic, Asus, Mikrotik) have their own mobile apps that can also generate heat maps using smartphone sensors. This integrated solution often proves more convenient than third-party software.
When choosing a program, pay attention to the support of your network adapter. Not all Wi-Fi cards support monitoring mode, which is necessary for scanning all channels, not just the one you're connected to.
Factors Affecting Signal Strength and Common Errors
Knowing how to measure a signal, it's important to understand what exactly influences it. Physical obstacles are Wi-Fi's main enemy. Concrete walls with rebar, mirrors, aquariums, and even tree foliage can significantly attenuate radio waves.
Frequency range also plays a role. The 2.4 GHz signal penetrates walls better, but is more susceptible to interference from household appliances (microwaves, Bluetooth). The 5 GHz band offers high speeds, but has a shorter range and is less able to penetrate obstacles.
A common mistake is installing a router in a niche, behind a TV, or on the floor. Router antennas should be positioned vertically and in an open area. Metal objects in close proximity to the antennas can completely block the signal in a certain direction.
It's also worth considering the number of connected devices and their activity. While this primarily impacts throughput, overheating of the router from constant load can lead to reduced transmitter power and unstable operation.
⚠️ Note: Router interfaces and firmware are updated regularly. The location of the Tx Power settings may change. If you don't find the setting in the specified location, check the official documentation for your model's manufacturer.
Analyzing the obtained data allows you to make a decision: relocate the router, replace the antennas with more powerful ones, switch to the 5 GHz band, or install a mesh system. Without precise measurements, these actions are essentially guesswork.
Frequently Asked Questions (FAQ)
Can the signal level be positive?
No, in the context of Wi-Fi reception, the signal is always negative (e.g., -50 dBm). Positive values can appear in the transmitter power (Tx Power) specifications, but not in reception. If you see a positive number in the RSSI field, it's most likely a display error or a specific software format.
Why is the signal good but the internet slow?
Signal strength (RSSI) only indicates radio wave strength. Speed depends on many other factors: channel congestion from neighbors, interference (SNR), provider restrictions, router processor power, and the capabilities of your device.
How to increase signal strength without buying a new router?
Try moving your router to a higher, more central location in your apartment. Replace your standard antennas with more powerful ones (higher gain). Make sure the router isn't located near a microwave or baby monitor. Switching to a less crowded channel may also help.
Does weather affect Wi-Fi signal strength inside the home?
The weather outside has no direct impact, as the walls protect against precipitation. However, high atmospheric pressure or lightning discharges can create electromagnetic interference, which could theoretically slightly increase the noise level, but for home Wi-Fi, this is negligible.