The stability of your wireless connection directly depends on the strength of the signal emanating from your router. Many users confuse the internet speed provided by their provider with the actual data transmission power over the air inside the room. Understanding the difference between these parameters is the first step to properly troubleshooting your home network.
A weak signal leads to packet loss, increased ping in games, and constant interruptions in the video stream. To fix these issues, you first need to obtain accurate data on the current airwaves. In this article, we'll discuss professional methods for measuring and interpreting the resulting data.
First, it's important to determine the specific points in your apartment or office where connection drops are occurring. Don't rely solely on the indicators in the corner of your smartphone screen, as they often only provide approximate information. You'll need more precise tools to get an objective picture.
Units of measurement and signal levels
The basic unit of measurement of radio signal power is dBm — decibel milliwatt. This is a logarithmic value, which can be confusing for beginners because the values are always negative. The closer the value is to zero, the stronger the signal, and vice versa.
For example, a value of -40 dBm is considered ideal and is only possible in the immediate vicinity of the router antenna. A value of -90 dBm means there is virtually no connection or is extremely unstable. Understanding this scale is critical for proper equipment configuration.
⚠️ Note: A difference of just 3 dBm means a twofold change in signal strength. Therefore, a jump from -60 to -63 dBm represents a significant loss in coverage quality.
There's also a relative signal quality scale in percentages, which is often used by Windows or Android operating systems for ease of understanding. However, for in-depth diagnostics and the identification of "dead zones," absolute values in dBm should be used.
Table of dBm and connection quality correspondence
-40...-50 dBm: Ideal signal (router in one room).
-50...-60 dBm: Very good signal (stable 4K video operation).
-60...-70 dBm: Good/Normal signal (web surfing without problems).
-70...-80 dBm: Weak signal (speed drops are possible).
-80...-90 dBm: Critical level (constant breaks).
Software diagnostic methods for PCs and laptops
The most accessible way to check signal strength is to use the operating system's built-in tools or specialized software. Windows has a hidden but extremely useful feature that allows you to view a detailed report without installing third-party software.
To run diagnostics, open a command prompt by typing cmd in the Start menu. Then enter the command netsh wlan show interfacesIn the list that appears, find the line "Signal", which will indicate the connection quality percentage.
macOS users can use the built-in Wireless Network Diagnostics utility. To do this, hold down the Option Click the WiFi icon in the menu bar and select "Open Wireless Network Diagnostics." From the "Window" menu, select "Scan" to see a list of networks and their strength in dBm.
Third-party apps offer a more user-friendly interface and graphical data representation. They allow you to monitor signal changes in real time while moving around the room, which is especially useful when finding the optimal location for your router.
WiFi Network Analysis on Android and iOS Smartphones
Mobile devices are excellent portable analyzers, allowing you to check your signal anywhere in your home. However, the approaches to collecting data on Android and iOS differ significantly due to Apple's security policies.
There are many free apps available on Android smartphones such as WiFi Analyzer, Network Cell Info or Fritz!App WLANThese programs provide access to raw adapter data, showing accurate power in dBm for all visible networks.
- 📱 Download the WiFi analyzer app from Google Play.
- 📶 Run the scan and wait for the network list to update.
- 📍 Move around the room, observing the change in the signal graph.
- 📝 Record the minimum values at the most distant points.
iPhone and iPad owners have a harder time getting accurate readings. Standard apps from the App Store don't have access to detailed WiFi chip data. The only way to see the exact dBm reading is to use debug mode, which is activated through the app. Apple Store (not to be confused with the App Store) and developer mode.
⚠️ Note: WiFi debug mode on iOS temporarily disables regular internet access. Be sure to deactivate it after testing to restore normal network operation.
To activate the mode on iOS: Download the AirPort app (or any Apple app) from the App Store, then open it and go to the Settings tab. Press and hold the WiFi logo or icon for a few seconds until the debug menu appears. Now, in the standard WiFi menu, tapping the network name will display technical information, including RSSI (signal strength).
A professional approach: measurements via the command line and Linux
For network administrators and advanced users, the most accurate data is provided by command-line tools and Linux-based operating systems such as Kali Linux or UbuntuThese methods allow you to obtain raw data without distorting the graphical interface.
In Linux systems, the main tool is the utility iwlist or iw. Team iwlist wlan0 scanning will display a detailed list of all available access points, indicating the signal level and quality.
iwlist wlan0 scanning | grep -E "ESSID|Signal level"This method is especially useful when automating data collection or conducting background monitoring. Scripts can record signal strength values at specified intervals, creating a detailed fluctuation graph.
Also worth mentioning is the utility netsh in Windows, which we mentioned earlier, but in the context of creating reports. The command netsh wlan show wlanreport Generates a detailed HTML file with connection and error history, which is saved in the system folder.
Factors Affecting Signal Strength and Quality
The signal strength you see on the screen is not a constant value. It changes dynamically under the influence of many physical and technical factors. Understanding these factors will help you correctly interpret your measurement results.
The first and most obvious factor is distance. The signal attenuates proportionally to the square of the distance from the source. However, indoors, the situation is complicated by the presence of obstacles. Walls, ceilings, furniture, and even people absorb or reflect radio waves.
Wall materials play a key role. Concrete walls with rebar shield the signal significantly more than drywall or wood. Metal structures, mirrors, and large surfaces containing water (aquariums) are significant obstacles to 2.4 GHz and 5 GHz waves.
The second important aspect is interference. In apartment buildings, the airwaves are oversaturated with signals from neighboring routers. If your router operates on the same frequency as five of your neighbors, this creates a "mess" that reduces effective throughput, even if the signal strength (RSSI) is high.
The third factor is the router's settings. Channel width, WiFi standard (802.11n/ac/ax), and transmit power (Tx Power) can be limited by software or regional restrictions.
| Let | Effect on signal (approximate) | Frequency |
|---|---|---|
| Open space | No losses | 2.4 / 5 GHz |
| Wooden door/wall | 2-5 dBm | 2.4 / 5 GHz |
| Brick wall | 10-15 dBm | 2.4 / 5 GHz |
| Concrete wall (20 cm) | 20-30 dBm | 2.4 / 5 GHz |
| Tinted glass | 15-20 dBm | Mainly 5 GHz |
2.4 GHz and 5 GHz Frequency Bands: Comparison of Characteristics
Modern routers operate in two main bands, and signal strength testing should be performed separately for each. These bands behave differently in indoor conditions.
Range 2.4 GHz It has better penetration. It bends around obstacles and passes through walls better, providing coverage over a larger area. However, this range is highly noisy, as it is used not only by WiFi networks but also by Bluetooth devices, microwaves, and baby monitors.
Range 5 GHz It provides much higher speeds and is less susceptible to interference from household appliances. However, it has a significant drawback: it penetrates obstacles less effectively and fades more quickly over distance. Therefore, in a distant room, a 5 GHz signal can be significantly weaker than a 2.4 GHz signal.
1. Check the 2.4 GHz signal in the far room.
2. Check the 5GHz signal at the same point.
3. Compare the difference in dBm.
4. If 5 GHz is weaker by 20+ dBm, consider installing a repeater.-->
When taking measurements, be sure to switch devices between networks (SSIDs) to get the full picture. It often happens that a phone "locks on" to the long-range but slow 2.4 GHz band, ignoring the faster 5 GHz band, which simply doesn't penetrate the wall.
Interpretation of results and solutions to problems
Once you've collected the data, it's time to analyze it. If the signal level at key points (workspace, sofa, bed) is below -75 dBm, you need to take steps to improve the situation.
The first thing you can do is change the router's location. Raise it higher, away from niches, metal enclosures, and microwave ovens. Sometimes, moving the router 50 centimeters to the side can increase the signal by 5-10 dBm.
The second step is channel setup. Use the scan data to select the least crowded channel. For 2.4 GHz, use only channels 1, 6, or 11, as they don't overlap.
⚠️ Note: Router interfaces and firmware are constantly being updated. The location of the Tx Power settings may vary. If you don't find the "Signal Strength" setting, check the official manual for your model.
If software methods and rearranging furniture don't help, consider hardware upgrades to your network. This could include replacing antennas with more powerful ones (if your router model allows it), installing a mesh system for larger apartments, or using PowerLine adapters that transmit internet through electrical wiring.
Frequently Asked Questions (FAQ)
Why is the internet speed low although the signal level is high (-45 dBm)?
A high signal strength (RSSI) simply means that the device is "hearing" the router well. However, low speeds can be caused by high channel noise (interference), ISP data caps, an overloaded router processor, or the use of an older WiFi standard (e.g., 802.11g/n instead of ac/ax).
Can foil or a metal object enhance the signal?
Theoretically, metal shields can redirect the signal in the desired direction (the reflector principle). However, in home settings, homemade foil structures often create chaotic reflections and dead zones rather than actually improve the situation. It's better to use certified directional antennas.
Does the number of connected devices affect signal strength?
No, the number of devices does not affect the antenna's physical radiated power (dBm). However, each new device shares the channel (air) bandwidth. With a large number of clients, the router may reduce the speed for each one, creating the illusion of a "weak" signal, although the RSSI level remains the same.
Which Android app is the most accurate?
One of the most popular and functional is considered to be WiFi Analyzer (open source)It's free, ad-free, and provides accurate dBm data, as well as channel occupancy graphs. Apps from router manufacturers are also good, for example, Tenda WiFi or TP-Link Tether, if they support your model.
Is it worth buying a signal amplifier (repeater) if the signal is -80 dBm?
A repeater can help, but it's important to understand that it cuts WiFi speed by about half because it operates in half-duplex mode (receiving and transmitting on the same frequency). At -80 dBm, a repeater may receive a poor signal and transmit "garbage" further. In such cases, it's more effective to use a mesh system or extend a twisted-pair cable into the affected room and install a second access point there.