Redmi series smartphones have long proven to be affordable and reliable devices, but the Redmi 9A sometimes faces problems with signal reception, which can be due to both the software features of the MIUI shell and the physical limitations of the antenna module in the budget segment.
Before you can find complex solutions, you need to do a basic diagnosis. SIM-maps, outdated access point settings or even a protective case that shields the signal. In this article, we will discuss step-by-step actions that will help stabilize the operation of the communication module and return comfortable use of the gadget.
Note that Xiaomi software optimization sometimes aggressively manages power consumption, which can adversely affect the operation of the radio module in the background. The specific problem of the Redmi 9A is the sensitivity of the antenna to the location of the fingers while horizontally holding the device.
Diagnosis and verification SIM-map
The first step in fixing communication problems is to check the physical condition. SIM-Often the cause of failures is oxidized contacts or mechanical damage to the chip, which occurs when you change cards frequently, contacts must be clean and not have visible scratches. If the card has been used for more than three years, it is advisable to replace it in the cabin of the operator with a new one that supports modern standards.
It's also important to check if the card is installed correctly in the tray. In the Redmi 9A, the tray is combined, and loose fit can lead to periodic breaks in the connection. Make sure the card is flat and does not hang inside the slot. Sometimes it helps to gently wipe the contacts with a soft eraser or an alcohol napkin.
And the compatibility of formats is not to be ignored. 4G/LTE, and if SIM-The card is very old, it may not work properly with new towers. Telecom operators often provide a replacement card service for free or for a nominal fee, while maintaining your number and rate.
☑️ Verification SIM-map
If the problem persists after the card is replaced, it may be the settings of the slot itself. In dual-symbol devices, it is better to assign priority to the slot with better coverage. → SIM-Maps and mobile networks and select your preferred card for Internet and calls.
Setting up the parameters of the mobile network
One of the common causes of bad reception is the wrong type of network, and the automatic mode does not always switch between standards correctly. 2G/3G/4G, Especially in areas with unstable signals, forced switching to a specific standard can stabilize the connection. → SIM-maps and mobile networks → Choice of network.
The network type selection menu recommends experimenting with modes. If you're in a city where LTE coverage is great but the speed is low, try switching to 3G Prefered temporarily. Sometimes 3G base stations are less loaded, which gives you a more stable, though not as fast, Internet. In rural areas, on the contrary, it's worth choosing 4G Prefered so that the phone doesn't get stuck on EDGE.
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If you’re constantly in a low signal zone, try switching the network type to 3G Only. The speed will be lower, but calls will become more stable, as the phone will stop wasting resources on finding lost 4G.
The choice of operator is also an important parameter. → SIM-maps and mobile networks → Settings SIM Make sure that the "Select Network Auto" function is enabled, however, if the phone is constantly jumping between the towers of different operators (roaming), it is better to manually select your provider from the list of available networks.
Resetting network settings to factory
If manual changes don't work, you should reset your network settings completely, and this procedure will bring all mobile Internet, Wi-Fi and Bluetooth settings back to their original state by removing accumulated software errors. It's important to understand that network resets don't affect your personal files, contacts or applications, but you will have to re-enter your saved Wi-Fi passwords.
To reset the Xiaomi Redmi 9A, go to Settings → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth. In the window that opens, click Reset. After rebooting, the device will re-register in the operator’s network, receiving the latest configuration options.
What happens when you reset your network settings?
Once reset, the phone can actively search for the network for a while, which will lead to increased battery consumption. 15-20 The signal is not stabilizing, check if it is activated. SIM-map in the settings menu, as sometimes after resetting the activation slider may shift.
Registration in the network and the choice of the operator
In some cases, the phone gets stuck on a tower with a bad signal, ignoring the more powerful base stations nearby. Forced re-registration on the network often solves this problem. The easiest way is to turn on Flight Mode for 10-15 seconds, and then turn it off, which will cause the radio module to completely reboot and find the best signal available.
A deeper method is manual network selection. Go to Settings. → SIM-maps and mobile networks → Select the network and turn off the automatic mode. The phone will start scanning the airwaves and give you a list of all available carriers. Choose your provider from the list. If the network is not caught, choose another operator for a couple of seconds, and then go back to your own provider.
It's worth noting that in dense urban areas or in the subway, manual network selection may be less efficient, as the phone is constantly moving between cells, and in such situations it's better to leave automatic mode, but periodically reboot the device to update registration data.
Use of engineering menus and hidden settings
For advanced users, there is an option to access the engineering menu, where you can fine-tune the signal reception settings. On Xiaomi phones, it is often accessed through a set of special code in the Phone app. Try entering the code ##4636##. If the menu opens, select Phone Information.
In the menu that opens, find the section "Set up your preferred network type." Here you can see a list of modes of operation of the radio module. LTE/CDMA ev-do auto (PRL) or similar supportive option 4G. Experimenting with other modes can result in a complete loss of communication, so be careful.
| Parameter | Description | Recommendation |
|---|---|---|
| Preferred type of network | Modem modem | LTE/TD-SCDMA/GSM (Auto) |
| Ping time. | Delayed response of the server | Less than 100 ms |
| Signal level (dBm) | Power of the received signal | Above -105 dBm |
| SIM status | Card connection status | Connected |
If the code doesn't work, your version of MIUI may be blocking access to the menu, so you can use third-party apps from Google Play, like NetMonster or CellMapper, that let you view connected towers and switch network modes without root rights.
The influence of environment and accessories
And don't forget the physical impact on the antenna. The antenna lines in Redmi 9A are located around the perimeter of the body. The dense metal cases, magnetic-clasp cases, or thick protective glass can shield the signal, reducing its level by 10-20%. Try removing the case and check if the connection has improved.
Also important is the position of your hands when you're talking, and if you're snugly sliding around the bottom of your smartphone with your palm, you can actually close one of the antennas, which is known as the "death grip," and try changing the grip of your device or using your headset to make calls in areas of insecure reception.
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Physical obstacles, such as metal covers or thick walls, affect communication quality more than software settings. Always check the phone without accessories when diagnosing problems.
Interference from other electronic devices can also cause interference: Microwave ovens, powerful Wi-Fi routers, and power lines can make noise on the air. If poor communication is only seen in a certain place (such as in the kitchen or in the office), try moving to another room or closer to the window.
Update and reset to factory settings
Xiaomi regularly releases firmware updates that contain fixes for radio module errors. Make sure your device has the latest version of MIUI installed. Check for updates in the Settings menu → About Phone → MIUI version.
If the problem has occurred after a recent update, there may be a bug in the new version. In this case, it is worth waiting for the next patch or, if the situation is critical, consider rolling back on the previous stable version of the firmware (you need to unlock the bootloader).
⚠️ Warning: Before performing a full Hard Reset, make sure to back up all important files, contacts, and photos.This procedure will completely remove all information from the phone’s internal memory, returning it to the “out of the box” state".
If none of the software methods worked, the last resort is a complete factory reset, which eliminates the impact of third-party applications and system conflicts. Performs through Settings → Phone → Reset → Erase all data. After reset, configure the phone as new without restoring the app backup immediately to check the communication on the “clean” system.