Xiaomi Redmi 4X (codenamed santoni) remains popular even years after its release, thanks to its balance of price, performance and reliability, but many users have questions about the quality of communication: why in some places the signal is lost, how to hold the phone correctly during a call, and most importantly, where the antennas are located in this device, the answers lie in the design of the device, and today we will discuss them in as much detail as possible.
Unlike flagship models, where antenna lines are often placed on the back in the form of decorative stripes, in the Redmi 4X, their placement is less obvious. It is a budget device with a metal body, and metal is known to shield the signal. Xiaomi engineers solved this problem in an unusual way — and that is why the antennas are hidden here not where many expect. Next you will learn how to find them, how they work and what to do if the connection leaves much to be desired.
Xiaomi Redmi 4X: Why the antennas are hidden
The Redmi 4X is made of aluminum-magnesium alloy with plastic inserts at the top and bottom, and these inserts are not just decor, they're splitting the metal frame into segments, preventing the formation of a closed screen that would block radio waves, and it's in these plastic areas that the main antenna modules are hidden.
Here are the key design features that affect the placement of antennas:
- 📶 Top plastic insert - here is the main antenna for mobile communication (2G/3G/4G) It's integrated into the module with the headphone jack.
- 📱 Lower plastic insert - contains an additional antenna to improve reception in mode MIMO (for 4G and wifi 5 GHz), and also antenna GPS/GLONASS.
- 🔋 Internal location – part of the antenna tracks passes under the battery, which complicates their visual detection without disassembly.
Interestingly, the Redmi 4X uses Laser Direct Structuring (LDS) technology, which lasers antenna tracks onto plastic parts in the body, to make them less visible but also more efficient, but it also has a downside: if you get a lot of mechanical stress (like falling), the antenna tracks can get damaged, which can lead to poor communication.
The exact location of antennas: diagram and photo
To understand exactly where the antennas in Xiaomi Redmi 4X are located, consider their location by housing zones:
| The hull area | Type of antenna | Responsible functions | Sensitivity to blocking |
|---|---|---|---|
| Top plastic insert (near the 3.5 mm connector) | Main (Main) | 2G/3G/4G, Wi-Fi 2.4GHz, Bluetooth | High (not to close with your hand!) |
| Lower plastic insert (near microUSB) | Supplementary (Diversity) | 4G MIMO, Wi-Fi 5 GHz, GPS/GLONASS | Medium |
| Under the battery (left side) | NFC-antenna (if present) | Contactless payments | Low. |
| Inside the metal body (right side) | Support tracks | Main signal amplification | Low. |
In practice, this means that when talking, it is not recommended to close the top of the phone with your palm - this can weaken the signal by 10-30%, and avoid using cases with metal elements or magnets in the area of antenna inserts.
For clarity, we give a conditional diagram (if you look at the phone from behind):
┌───────────────────┐
│ PLASTIC (antenna) │ ← Upper zone (main antenna)
├───────────────────┤
│ METALL │
│ (shielded) │
├───────────────────┤
│ PLASTIC (antenna) │ ← Lower zone (additional antenna)
└───────────────────┘💡
If you notice that the signal is lost when holding the phone in a certain way, try turning it in your hand or using a headset, often the problem is solved by changing the position of the hand relative to the antenna area.
How to check the quality of communication and diagnose problems
If you suspect that the Redmi 4X antennas are not working properly, you should first check the real quality of communication.
- Go to Settings → About Phone → General Information → SIM-card status.
- Note the signal level (in dBm) and network type (e.g. LTE or HSPA).
- For a more detailed diagnosis, enter the engineering menu by dialing ##4636##, then select Phone Information.
Normal signal readings:
- 📶 -70 dBm and higher is a great signal.
- 📶 from -85 before -70 dBm - medium (possible interruptions).
- 📶 below -100 dBm is a weak signal (you need to look for a cause).
If the signal is permanently weak, the problem may be:
- 🔌 Damage to antenna tracks (for example, after falling or disassembling).
- 📱 Malfunctions SIM-card or slot (try moving the card to another slot or phone).
- 📡 Operator problems (check the connection on another device in the same place).
What does a damaged antenna look like?
Common Causes of Signal Deterioration and How to Remove Them
Even if the antennas in the Redmi 4X are in good condition, communication can be degraded due to external factors.
⚠️ Note: Using metal covers (such as magnetically fastened ones) can block up to 50% of the signal. If you notice a deterioration in communication after installing a new case, try removing it and testing the reception.
| Problem. | Possible cause | Decision |
|---|---|---|
| The signal disappears when holding the phone | Hand closes antenna area | Use a headset or hold your phone differently |
| Bad indoor reception. | Thick walls, metal structures | Switch to 3G or use Wi-Fi Calling |
| 4G is not working smoothly | Weak LTE signal in the region | Manually select 3G network in settings |
| GPS has been searching for satellites for a long time | Poor GPS antenna contact | Check the integrity of the lower plastic insert |
If the problem is not solved by software, you may need to check the antenna contacts on the motherboard.
Check the integrity of plastic inserts|Check the antenna contacts on the board (under the battery)|Test your phone without a cover|Update the firmware to the latest version-->
Can I improve the reception of the signal by myself?
To amplify the signal on Xiaomi Redmi 4X without disassembling the phone in several ways:
- Firmware update. Manufacturers often optimize modems in newer versions of MIUI. Check for updates in Settings → About Phone → System Update.
- Manual network selection. Automation doesn't always choose the optimal network. 3G or LTE In Settings → SIM-maps and mobile networks → Type of network.
- This will require an adapter with a TS9 connector (connects to the headphone socket) and a passive antenna, which is relevant for areas with very weak signal.
More radical methods (such as soldering additional antennas) require disassembling the phone and experience with electronics. If you are not sure of your skills, you should contact a service center.
⚠️ Warning: Attempting to modify antennas yourself (e.g. soldering new tracks) may result in a loss of warranty (if it is still valid) or a complete failure of the communication module. SIM-map.
💡
The most effective and secure way to improve communication is to use Wi-Fi Calling and VoLTE (if your carrier supports them), which will allow you to make calls over the Internet, regardless of the quality of the mobile network.
What to do if the antenna is damaged: repair and replacement
If the test shows that the antenna is physically damaged (for example, after falling or getting moisture), it will need to be replaced. In Redmi 4X, antenna modules are not sold separately, they are soldered into plastic inserts of the housing.
- 🔧 Replacement of plastic insert (if only it is damaged).
- 📱 Soldering of antenna contacts on the motherboard (if the tracks have left).
- 🔄 Complete replacement of the body (in extreme cases).
The cost of repairs in service centers varies:
- Replacement of plastic insert: ~500-1000 rubles.
- Interpling of contacts: ~1500-2500 rubles.
- Replacement of the body: ~2000-3500 rubles (depending on the configuration).
If you decide to repair your phone yourself, you will need:
- Plastic mediator for disassembly.
- A soldering station with a thin sting (for contacts).
- New plastic insert (can be found on AliExpress or in Xiaomi parts stores).
The process of disassembling the Redmi 4X requires caution - under the back cover are the plumes of the fingerprint and main camera, which are easily damaged.