The quality of mobile communications directly affects the speed of loading pages, the quality of voice calls and the stability of messengers. Users often notice that the connection “flies” on one smartphone, while on another, located in the same room, it constantly disappears. The difference lies not only in the location of the operator tower, but also in how the device interprets and displays the received signal.
The standard “sticks” in the corner of the screen are just a conventional graphic indicator that manufacturers configure in different ways. To accurately diagnose communication problems, it is necessary to understand the physical quantities measured in decibel milliwatts (dBm). It is these numbers that allow you to objectively assess the state of the radio channel between your Androidsmartphone and the operator’s base station.
In this article we will analyze which values are considered excellent and which indicate critical problems. You will learn how to enable the engineering menu to view real indicators and what actions to take if the signal level drops below acceptable standards.
Signal strength units: dBm and ASU
The main metric of radio signal quality is power, which is measured in negative values dBm (decibel-milliwatt). The value scale usually varies from -50 to -120 dBm. The closer the number is to zero, the stronger and better the signal. For example, -60 dBm is significantly better than -90 dBm.
In parallel with dBm, the Android system uses the parameter ASU (Arbitrary Strength Unit). This is a relative value that depends on the type of network (2G, 3G, 4G/LTE, 5G). The ASU value is always positive: the higher it is, the better the connection. The conversion between these values is carried out using formulas that are different for each generation of networks.
For the LTE (4G) network, the relationship is as follows: the signal level in dBm is -140 + (ASU * 2). This means that if your smartphone shows 50 ASU, then the actual signal level is approximately -40 dBm, which is ideal.
⚠️ Attention: DBm values are always negative. An error in the sign (perceiving -80 as 80) will lead to an incorrect conclusion about the quality of the connection. Remember: -50 dBm is an excellent signal, and -110 dBm is a weak signal area.
Understanding the difference between these units is critical when using third-party network analysis applications. Many utilities show only ASU, which can confuse an inexperienced user who does not know the conversion formulas for a specific type of network GSM or UMTS.
If you see an ASU value of 99 or 255 in the phone menu, this means that the smartphone cannot determine the signal level or is not registered in the operator's network.
Norms and acceptable signal level values
Not all “sticks” on the screen are the same. Different manufacturers set different indicator thresholds. However, the physical standards for signal reception are universal for all devices based on Android. Below is a table to help decipher the status of your network.
| Signal level (dBm) | ASU value (LTE) | Quality rating | Description of status |
|---|---|---|---|
| -50 ... -70 | 45 ... 97 | Excellent | Ideal speed, calls without interference, work close to the tower. |
| -71 ... -85 | 30 ... 44 | Good | Stable Internet, high-quality voice communication, standard situation in the city. |
| -86 ... -100 | 15 ... 29 | Average | Speed drops are possible, video may be buffered, calls are stable. |
| -101 ... -110 | 5 ... 14 | Bad | Unstable 4G, switching to 3G/2G, dropped calls, high battery drain. |
| -111 ... -120 | 0 ... 4 | Critical | Loss of network, inability to make a call, only emergency services work. |
If your smartphone is constantly in the “Bad” or “Critical” signal zone, this leads to accelerated battery wear. The communication module is forced to operate at maximum search power, which causes heating of the case and rapid discharge.
It is worth considering that indoors the signal level is always lower than outdoors. Walls, especially those reinforced with concrete or with metal coating on glass, can shield up to 20-30 dBm. Therefore, an indicator of -90 dBm inside a building can be considered normal if it is -60 dBm outside.
How to see the exact signal level in the Android menu
The standard interface does not always show numbers. To see the exact values in dBm and ASU, you need to use the hidden menu or “About phone” settings. The access method depends on the version Android and the manufacturer’s shell (MIUI, OneUI, ColorOS).
The most universal method is to use a special code in the “Phone” application. Enter the combination ##4636##. If the code works, the “Check” menu will open, where you need to select “Phone Information”. There you will see the lines “Signal strength” and network type.
On some modern smartphones, this code may be blocked by the manufacturer. In this case, the path is through the settings: go to Settings → About phone → All characteristics → SIM card status. Depending on the model, the signal level may be displayed immediately or require several clicks on the “IMEI” or “Status” item.
☑️ Checking the signal through settings
If the built-in methods are not give results, you can use third-party utilities from Google Play, such as Network Cell Info or Signal Check Pro. These apps not only show the current level, but also plot signal changes over time, which is useful for finding “dead spots” in the house.
⚠️ Attention: On smartphones with two SIM cards, the signal level may be different for each of them, even if they are connected to the same operator. Check the settings for the SIM card through which data is transferred.
Factors affecting the quality of network reception
Why does the signal fluctuate? The propagation of radio waves is influenced by many physical and technical factors. Understanding these reasons will help you position your smartphone correctly or choose a place to make a call.
First, the distance to the base station and line of sight. Forests, hills and dense urban areas create shadows and signal reflections. Secondly, wall materials. Metal siding, mirrors and tinted car windows greatly weaken the high-frequency bands of LTE and 5G.
Thirdly, the design features of the smartphone itself. Antennas in modern devices are built into the body. If you hold the phone in a metal case or cover the antenna area with your hand (usually the top or bottom of the frame), the signal may drop by 10-15 dBm instantly.
It is also worth mentioning network congestion. During peak hours, when thousands of users simultaneously try to download videos or access social networks, channel throughput drops. In this case, the signal level (dBm) may remain high, but the Internet speed will be zero due to the high level of noise and interference.
The influence of weather on communications
Rain and snow can weaken the signal slightly, especially at high frequencies (above 2 GHz), but for the average user this change is usually not noticeable. Atmospheric pressure and humidity have a much stronger effect during a thunderstorm.
Ways to strengthen the signal on a smartphone
If you find that the signal level is in the red zone, you can take a number of actions to improve the situation. Start with the simplest thing - rebooting the device. This forces the modem to re-register with the network and select the most suitable base station.
Try manually selecting a telecom operator. Go to your network settings and turn off automatic selection. After scanning available networks, force select your operator. Sometimes the phone “clings” to a distant tower with a better signal, but high latency, instead of a nearby one.
Another effective method is switching the network mode. If the 4G signal is weak (below -110 dBm), the phone spends a lot of energy maintaining the connection. Forced switching to Only 3G or Only 2G mode can give a more stable, albeit slower connection, since low-frequency ranges penetrate walls better.
For advanced users, it is possible to change the frequency range through the engineering menu. However, this requires caution. Incorrect settings can lead to complete loss of communication. Commands are entered through the same menu ##4636## in the “Set up preferred network type” item.
⚠️ Attention: The use of external antennas and signal amplifiers (repeaters) must be consistent with the legislation of your country. An incorrectly configured amplifier can interfere with the operation of operator base stations, which can result in fines.
The easiest way to improve the signal indoors is to go to the window, preferably on the side of the building where the operator tower is located, and remove the case from the smartphone.
Frequent problems and their decision
Users often encounter a situation where the indicator shows a full signal, but the Internet does not work. This phenomenon is called "false signal". It occurs when the phone sees the tower's pilot signal, but cannot establish a full connection due to channel congestion or problems on the provider's side.
Another common problem is rapid discharge with a weak signal. As mentioned earlier, below -105 dBm, the phone's transmitter power increases many times over. If you are in an area with unstable reception for a long time, turn on airplane mode for a few seconds and then turn it off to reset the connection.
It is also worth checking the integrity of the SIM card. Old or damaged cards may have poor contact with the reader, which is interpreted by the system as a loss of signal. Try wiping the contacts of the SIM card with an eraser or replace it with a new one at the operator's salon.
If none of the software methods help, there may be a hardware problem. Damage to the antenna module after a fall or moisture requires contacting a service center. Antenna diagnostics on Android are possible using special test applications.
Why is the signal level constantly jumping?
Signal jumps (for example, from -70 to -100 dBm) are usually caused by the interference of waves reflected from buildings or by user movement. It could also be a sign of network congestion when the phone tries to switch between different frequency bands on the same tower.
Does the case affect the reception level?
Yes, especially if the case contains metal inserts, magnets or is made of thick metal. Such materials shield smartphone antennas. Silicone and plastic cases have virtually no effect on the quality of communication.
What are RSQ and SINR in the engineer's menu?
RSQ (Reference Signal Received Quality) and SINR (Signal to Interference plus Noise Ratio) are indicators of signal quality, not its power. They show the noise level. A high signal level (dBm) with a low SINR means that the channel is “noisy” and the Internet speed will be low.
Is it possible to improve the signal using software?
Programmatically you can only optimize the choice of network or frequency. It is impossible to increase the physical reception power of the antenna with the app. Applications that promise to “boost the signal by 100%” most often simply clear the network cache or reboot the radio module.
Why is the signal worse on the new phone than on the old one?
New smartphones support more frequency bands and technologies (frequency aggregation), which makes them more sensitive to interference. In addition, in pursuit of design (glass and metal), manufacturers are sometimes forced to place antennas less successfully than in old plastic cases.