The stability of an internet connection directly depends on the quality of the wireless signal, but standard indicators on a smartphone screen or laptop tray often provide only a rough, and sometimes misleading, picture of the actual situation. When a video conference drops out and pages load slowly, a deeper analysis is needed beyond simply checking the number of bars in the corner of the screen.
Understanding how router radiated power is measured and what values are considered normal will allow you to accurately determine whether you need to relocate equipment, replace antennas, or use repeaters to expand your coverage area.
In this article, we'll explore the technical nuances of measuring radio signal strength, examine hidden operating system functions, and examine specialized software used by network engineers to create coverage maps.
Units of measurement and standards: what is dBm?
The basic unit of measurement of signal strength in wireless networks is dBm (decibel milliwatt). This is a logarithmic relative unit that shows the power level relative to 1 milliwatt. A key feature, often overlooked by beginners, is that the values are always negative, as the received signal level is always weaker than the reference milliwatt.
The closer the value is to zero, the stronger the signal. For example, a value of -30 dBm is practically ideal and is only possible when in close proximity to the access point without physical obstacles. Conversely, a value of -90 dBm means there is virtually no connection, and the device is about to lose the network connection.
⚠️ Attention: Don't confuse dBm with dB. While dBm is absolute power, dB (decibel) is used to indicate a change in signal level (gain or attenuation). Antenna gain is always specified in dBi (relative to an isotropic radiator).
Certain thresholds exist for comfortable operation of various services. Web surfing may be possible even with low values, but streaming 4K video or online gaming requires a stable and strong signal. Below is a table to help interpret the obtained values.
| Range (dBm) | Signal quality | Possibilities of use |
|---|---|---|
| -30 ... -50 | Ideal | Any tasks, including VR and 8K streaming |
| -51 ... -65 | Excellent | Stable operation of all applications, online games |
| -66 ... -75 | Good | Comfortable surfing, HD video, video calls |
| -76 ... -85 | Weak | Web surfing and email only, interruptions possible |
| -86 ... -95 | Critical | The connection is unstable, packet data loss is high |
Understanding these ranges is critical when conducting initial network diagnostics. If your laptop shows -80 dBm a meter from the router, this is a clear sign of hardware or driver failure.
Checking signal strength on Windows without third-party programs
operating system Windows has built-in diagnostic tools that provide accurate digital data without the need to install additional software. The fastest way to find out your current connection strength is using the command line.
Open the terminal by typing cmd in the Start menu and run the command netsh wlan show interfacesIn the list that appears, find the "Signal" line, where the level will be displayed as a percentage. While percentages are easier to understand, they're less informative than dBm, but they provide a quick overview.
For more detailed information, including the current channel and communication standard, you can use PowerShell. Enter the command netsh wlan show all, which will output an exhaustive list of all available networks and their parameters.
It's also worth paying attention to the hidden Wi-Fi engineering settings menu. To activate it, launch the command prompt as administrator and enter:
netsh wlan set hostednetwork mode=allowHowever, for continuous real-time monitoring, it is more convenient to use the task manager or special widgets, if they are supported by the wireless adapter driver. Standard tools Windows 10/11 Good for a one-time check, but not for plotting decay graphs.
WiFi Analysis on Android and iOS Smartphones
Mobile devices are in our hands most often, so they are the most convenient way to conduct express diagnostics while moving around the apartment. On devices controlled by Android The situation with access to signal data depends on the OS version.
In older versions of Android (before 10), there was a hidden engineering menu that was called by the code ##4636##. You could select "Wi-Fi Details" to see the exact RSSI (Received Signal Strength Indicator) value in dBm. In modern versions, Google has closed this access for security reasons, so third-party apps are now required to obtain accurate data.
Why did Google close the engineering menu?
The company restricted access to low-level modem data to prevent inexperienced users from changing settings, which could lead to loss of connection to cellular towers or unstable operation of the radio module.
For users iPhone (iOS) accessing technical data is more difficult due to the closed ecosystem. The standard interface only displays "sticks." For detailed analysis, iPhone owners need to download the official app. AirPort Utility from Apple (if available in your region) or use the device's Mac address to log in to the router's admin panel.
In the AirPort Utility app, go to Settings (the gear icon in the corner) and turn on the "Wi-Fi Scanner" toggle. Then, in the list of networks, tap the desired access point, and you'll see detailed technical information, including channel, frequency, and signal strength.
When testing your smartphone, it's important to hold the device in the position you normally use it. The human body, which is mostly water, is an excellent absorber of radio waves and can block the signal if you cover the phone's antenna module with your hand.
Professional software for creating heat maps
If the built-in tools don't seem informative enough, specialized utilities can help. They don't just display the current number, but also allow you to create graphs, track change history, and visualize data.
One of the most popular programs for Windows is inSSIDerIt scans the airwaves, displaying all available networks, their channels, channel width, and signal strength. Its key feature is visualizing channel overlap, which helps you choose the least congested frequency range for your router.
For macOS users, a great choice would be WiFi ExplorerThis powerful tool provides detailed information about the Wi-Fi environment, including the signal-to-noise ratio (SNR), which is an even more important parameter than just signal strength. High noise levels can choke even a strong signal.
- 📡 Acrylic Wi-Fi Home — a free utility with a simple interface that displays a signal strength graph in real time.
- 📡 NetSpot — allows you to create heatmaps by loading a floor plan and walking through it with a laptop.
- 📡 WiFi Analyzer — a popular Android app that turns your phone into a professional analyzer.
Using such programs is especially important in apartment buildings, where dozens of neighboring routers create a welter of radio interference. Spectrum analysis helps determine whether the problem lies in a weak signal from your router or excessive noise in the air.
Factors affecting signal reception quality
Understanding the physics of radio wave propagation helps to correctly interpret measurement results. A WiFi signal is a radio wave, and it behaves predictably when encountering obstacles.
The first and foremost enemy is walls and ceilings. Concrete walls with reinforcement can absorb up to 90% of the signal. Metal structures, mirrors, aquariums, and even dense foliage of houseplants can significantly weaken the radiation passing through them.
⚠️ Attention: Microwave ovens operating at 2.4 GHz and wireless baby monitors can create significant interference when turned on. If the signal drops periodically, check the operating schedule of your appliances.
The second factor is distance. Signal strength decreases proportionally to the square of the distance (in free space). This means that if you're half as far away from the router, the signal weakens by a factor of four. Indoors, signal attenuation is even faster due to reflections and absorption.
The third factor is the finishing materials. Foiled insulation behind wallpaper or metallic threads in curtains can turn a room into a "Faraday cage," completely blocking the WiFi signal, even if the router is in the next room.
Testing methodology and network optimization
To obtain reliable results when testing WiFi signal strength correctly, you need to follow a specific methodology. Don't rely on a single measurement.
Start by creating a reference point. Stand 1-2 meters from the router and record the readings. This will be your "ideal" value for this equipment. Then move around your apartment, taking measurements at the points where you plan to use the devices.
☑️ WiFi Diagnostic Checklist
Be sure to test the network on both frequency ranges. Range 2.4 GHz penetrates walls better, but has low speed and high noise levels. Range 5 GHz Provides high speed, but fades very quickly when encountering obstacles.
If the signal drops below -75 dBm in "dead zones," consider optimization options. This could include replacing antennas with more powerful ones (with a higher dBi gain), moving the router to a hallway, or installing a mesh system that will create a single, seamless network instead of a single, powerful source.
Keep in mind that updating your router's firmware can also improve connection stability and signal processing algorithms, as manufacturers often improve their software for managing transmission power.
What to do if the signal is strong, but the internet is slow?
A high signal level (for example, -40 dBm) does not guarantee high speed. The issue could be channel interference (neighbors on the same channel), ISP throttling, router CPU overload, or server-side issues. Check your speed with Speedtest and compare it to your plan.
Does the direction of the router antennas affect the signal strength?
Yes, it does have a significant impact. Router antennas typically have a "doughnut"-shaped radiation pattern. The signal radiates perpendicular to the antenna. If the antenna is pointing vertically upward, the signal spreads better horizontally. For multi-story buildings, it is sometimes recommended to position the antennas horizontally or at a 45-degree angle.
Can weather affect indoor WiFi?
The weather outside doesn't directly affect the indoor signal, as the walls protect the network. However, a strong thunderstorm can create electromagnetic interference, and high humidity (fog, heavy rain) theoretically slightly increases radio wave attenuation, although this is negligible in an apartment.