The problem of unstable Internet or dropped calls is familiar to every smartphone user. We often chalk this up to poor operator performance, but the culprit isn't always at the cell tower. Often the reason lies in the settings of the device itself or physical obstacles. To understand the true state of affairs, it is necessary to diagnose the quality of the connection.
The standard “sticks” in the upper corner of the screen give only an approximate idea of the quality of the connection. They do not show the real level of signal strength in decibels, which is critical for the stable operation of 4G/LTE networks. In this article we will analyze professional diagnostic methods available on any device under control Android.
You will learn to read the technical parameters of the radio module, use hidden engineering menus and correctly interpret the received data. This knowledge will help you find a “dead zone” in an apartment or understand whether it is worth changing your telecom operator.
Understanding signal units: dBm and ASU
Before moving on to practical actions, it is important to understand the terms. The signal level is measured in negative decibel-milliwatt values (dBm). The closer this number is to zero, the better the connection quality. For example, -50 dBm is considered excellent, while -110 dBm indicates almost complete absence of network.
The second parameter is ASU (Arbitrary Strength Unit). This is a relative value that is used by the operating system to convert it into “sticks” that the user can understand. Knowing the conversion formula, you can always determine the real signal strength, even if the smartphone interface hides the numbers.
It is worth noting that different generations of networks (2G, 3G, 4G) have their own ranges of acceptable values. For LTE, the normal operating range is considered to be -80 to -100 dBm. If the value drops below -115 dBm, the phone may periodically lose network or switch to a slower communication standard.
⚠️ Attention: Signal values fluctuate constantly depending on your location, weather and tower load. Do not draw conclusions based on one measurement - conduct a series of tests at different points in the room.
To quickly convert ASU to dBm, use the formula: dBm = (2 * ASU) - 113 for GSM networks. For LTE, the formula may differ depending on the chipset manufacturer.
Using the engineering menu via USSD codes
The fastest way to access technical information about the radio module is to use special service codes. These commands open a hidden menu intended for engineers and testers. The interface may differ depending on the manufacturer of your smartphone (Samsung, Xiaomi, Huawei).
On most devices with blank Android or shells from Motorola i Sony a universal code works. You need to open the “Phone” application and enter the sequence of characters. After entering the last digit, the menu should open automatically, press the button no call required.
##4636##If this code does not work, try alternative options that are often used by Chinese manufacturers. In the menu that appears, select “Phone Information” Here you will see detailed connection statistics.
- 📶 Signal strength: Current signal level in dBm and ASU.
- 📡 Network type: Current network type. (LTE, HSPA, GSM).
- 🔒 Cell ID: Unique identifier of the base station to which you are connected.
- ⚙️ Radio state: Radio module status (on, off, in search).
Device owners Samsung may require a different code, since their One UI shell has its own structure of service commands. Try entering *#0011# to enter Service Mode. There, the information is presented in the form of logs, where you need to look for the line RSSI.
Checking the signal through the Android system settings
If using codes according to For some reason it is impossible or the menu does not open, you can use the built-in tools of the system. Starting with version Android 11, Google has added the ability to display the exact signal level directly in the status bar, although this function is often hidden by default.
To activate the display of values in decibels, go to section Settings → About phone → All characteristics. Find the item “Kernel Version” or “Build Number” and quickly click on it 7-10 times. This will activate developer mode if it is not already enabled.
Next, return to the main settings menu and go to the new section System → For developers. In the list of options, find the “Show signal strength in dBm” switch. After activation, numbers will appear next to the network icon.
| DBm value | Communication quality | Probable speed | Recommendation |
|---|---|---|---|
| -50 to -70 | Excellent | Maximum | Do nothing |
| -71 to -85 | Good | High | Stable operation |
| -86 to -100 | Average | Average | Possible failures |
| -101 to -115 | Bad | Low | Search for a place with the best signal |
| Below -115 | Critical | Absent | Network loss |
This method is convenient because it allows you to monitor the signal in real time while moving around your apartment or office. You do not need to constantly go into the engineering menu, just look at the top line of the screen.
Enabling dBm display in the developer settings is the safest and most visual way of monitoring for the average user, which does not require entering complex codes.
Third-party applications for detailed diagnostics
Standard system tools often provide a limited set data. For in-depth analysis of the radio frequency spectrum and selection of the best base station, it is better to use specialized software. Application stores offer many utilities, but not all of them are equally useful.
One of the most popular and reliable tools is the application Network Cell Info Lite. It doesn't just show numbers, but also visualizes the location of the towers on a map using Google Maps data. This helps you understand which tower serves your phone and how far away it is.
Another powerful tool is G-NetTrack. This is a professional solution that allows you to log connections, check data transfer speeds and analyze switching between cells (handover). The application may be difficult for a beginner, but it provides comprehensive information.
⚠️ Attention: Many applications from the “Signal Boosters” category on Google Play are fakes. They cannot physically amplify a smartphone's antenna using software. Use diagnostic utilities only.
When installing such applications, be sure to grant them permissions to access geolocation and phone. Without these rights, the app will not be able to read data from the modem. Also note that constantly polling GPS and the network can increase battery consumption.
Why do applications show different numbers?
Different applications may poll the modem at different frequencies or use different data averaging algorithms. In addition, one application can show the signal of the current serving cell, and another - the total signal from all visible towers.
Factors affecting the quality of signal reception
Even if your smartphone is technically sound, external conditions can drastically deteriorate the quality of communication. Understanding the physics of radio wave propagation will help you find the optimal place to make a call or surf the Internet.
Building materials play a key role. Metal structures, reinforced concrete and energy-saving sprayed glass act as a Faraday shield, blocking the signal. In basements and elevators, communication is lost precisely because of shielding.
Weather conditions also make their own adjustments. Heavy rain, snow or thunderstorms can absorb and scatter radio waves, especially at the high frequencies used in 4G and 5G networks. In clear weather, the signal is usually more stable.
- 🏢 Building: Dense city blocks create a “radio shadow” effect, where the signal is reflected from buildings and goes out.
- 🌳 Terrain: Hills, ravines and dense forests prevent line of sight between the phone and tower.
- 👥 Load: During peak hours, when many people use the network at the same time, the speed drops even with a good signal level.
Sometimes the problem lies in the device itself. A damaged antenna after a fall, a poor-quality case with metal inserts or magnetic fasteners can reduce the sensitivity of the receiver. Try removing the cover and checking if the sensor readings change.
☑️ Diagnosing communication problems
How to improve cellular reception on a smartphone
If diagnostics show a low signal level, there are ways to correct the situation without purchasing expensive equipment. First of all, try to force switch the network type. Sometimes stable 3G is better than constantly dropping 4G.
Go to the mobile network settings (Settings → SIM cards and mobile networks → Network type) and select your preferred standard. Experimentally find the option that provides the most stable connection in your location.
An effective method is to reset the network settings. This action will remove saved APNs, Wi-Fi passwords, and paired Bluetooth devices, but often resolves radio software conflicts. The path to the function is usually located in the section System → Reset settings → Reset Wi-Fi, mobile data and Bluetooth settings.
⚠️ Attention: Before resetting the network settings, make sure that you know the password for your Wi-Fi network, as you will have to enter it again. Also check that your APN settings are up to date with your operator so that the mobile data works correctly.
In extreme cases, when none of the methods helps, you can consider installing an external antenna or signal repeater. However, for a regular smartphone, this requires a model with a connector for an external antenna, which is rare in modern devices.
Try going to a window or going out onto a balcony. Often, shifting the position of your body or phone by just 50 centimeters radically changes the signal level due to wave interference.
Frequently asked questions (FAQ)
Why does the signal level constantly fluctuate?
Signal fluctuations (ping-pong effect) occur when the phone is on the border of the coverage of two base stations. The device constantly tries to switch to a more powerful tower, but due to obstacles the signal from it is unstable. This may also be a sign of network overload by the operator.
Does fully charging the battery affect the signal level?
No, battery charge does not affect the sensitivity of the antenna. However, when the charge is low (less than 10%), some smartphones can artificially limit the transmitter power to save energy, which theoretically can worsen the signal sent to the tower, but not the reception.
What to do if the code ##4636## does not work?
Manufacturers can block access to the engineering menu in firmware for specific regions or operators. In this case, the only solution is to install third-party applications like Network Cell Info or obtain root access, which is not recommended for ordinary users.
Can a new SIM card improve the signal?
Yes, if your SIM card is very old (released more than 5-7 years ago). Old cards may not work correctly with modern encryption protocols and 4G/5G frequencies. Replacing the card in the operator's salon often solves the problem of unstable Internet.
Is it true that stickers on the antenna strengthen the signal?
No, that's a myth. Gold whisker or foil stickers have no physical basis for boosting the signal and in some cases can even shield the antenna, reducing reception. Do not waste money on such accessories.