Xiaomi smartphone owners often face a situation where the device stops confidently catching the network, and the first question arises about the technical condition of the communication module. Finding the answer to the question of where the antenna on the Xiaomi Redmi Note 9 Pro phone is located becomes critical when the signal level drops or the network is completely lost. Unlike old button phones, in modern gadgets, the antenna system is a complex set of plumes built into the body of elements and print tracks.
The design of this popular device involves integrating antenna lines directly into a plastic frame and using special contact areas on the motherboard. Incorrect diagnosis can damage fragile components, so you need to clearly understand the architecture of the radio module. In this article, we will discuss the layout of all communication elements in detail so that you can correctly diagnose or replace.
The architecture of the antenna system in the Redmi Note 9 Pro
The modern smartphone is not just a box with a screen, but a sophisticated radio instrument. In the Redmi Note 9 Pro (codename curtana), the antenna system is divided into several independent segments to ensure the operation of different frequency bands. The main antenna modules here are two: the top and bottom, which connect to the motherboard via coaxial cables.
The upper segment is usually responsible for the main GSM, 3G and 4G bands, as well as the operation of Wi-Fi and Bluetooth modules. The lower part of the design often takes over the functions of GPS and auxiliary frequency bands. Separating the zones allows you to minimize signal interference and ensure a stable data rate even in poor reception conditions.
⚠️ Warning: The interior layout of the Redmi Note 9 Pro is very dense.Do not try to remove antenna plumes without first turning off the battery, as there is a high risk of short circuit of the contact areas.
It's important to understand that the antenna is not always a separate stick, and in this device, the emitter is often a metallized part of the case or a special insert in the frame that connects to the board through spring contacts, and the disruption of contact between these elements and the board is the most common cause of communication problems.
Exact location of antenna module
If you're taking apart a smartphone and you're looking for exactly where the antenna is, you need to look at the top and bottom thirds of the case. The antenna plume in the Xiaomi Redmi Note 9 Pro is a flexible circuit board that encircles the inside of the frame, and it runs along the side faces where the plastic inserts are located.
The main connector to which the antenna cable connects is located on the motherboard at the top of the device, next to the charging connector (which, paradoxically, is at the bottom, but the main plume goes up), or in the immediate vicinity of the processor, depending on the revision of the board.
- 📍 The upper antenna group is located at the end above the screen and is connected to the main radio module.
- 📍 The lower antenna group is integrated into the frame around the charging connector and speaker.
- 📍 The coaxial cable connects along the left face (when viewed from behind) under the protective cover.
When you remove the back cover (which is glass and glued in this model), you get access to the plastic frame, and that's the frame that the antenna track is attached to, and the contact pads should fit tightly together, and if you see a gap or oxidation, the signal will be lost.
Diagnostics of problems with signal reception
Before disassembling the device, you need to make sure that the problem lies in the hardware, and not in a software failure or SIM-There are a number of symptoms that indicate that the antenna path or its connections are malfunctioning, and if the phone shows "No network" or constantly searches for the network, it can be a sign of a break.
You can use an engineering menu to do the initial check, dial ##4636## in the phone app, and this will open a test menu where you can see the signal level in dBm. The normal value is between -50 and -80 dBm. If the value is below -110 dBm, the antenna system is not working properly.
| Symptoms. | Probable cause | Action. |
|---|---|---|
| Continuous search of the web | The antenna contact dump | Checking the plume connection |
| The top is warming. | Short circuit in the chain | Urgently turn off and diagnose |
| Weak signal in the room. | Contact contamination | Alcohol cleaning and purging |
| Wi-Fi doesn't see the network | Upper module damaged | Replacement of the antenna unit |
It's also worth checking the integrity of the coaxial cable itself, which is very thin and easily clamped when assembled sloppy, and microcracks in the cable's braid cause the signal to fade even if the cable appears to be intact.
Instructions for replacing the antenna plume
Replacing the antenna with the Redmi Note 9 Pro requires precision and a special tool. You'll need suction cups, a thin mediator, a set of screwdrivers and tweezers. The process begins by heating the perimeter of the back cover to soften the glue.
Once the lid is removed and all the screws of the plastic frame are unscrewed, you need to turn off the display plumes and the batteries, and then you can start working with the antenna system, and carefully disconnect the connector of the antenna cable from the motherboard.
☑️ Checklist before replacing the antenna
The old antenna block is carefully removed from the slots of the plastic frame. Notice how it is stacked so that the new one fits perfectly into its place. The new plume is set in reverse order, and then the frame is screwed and the rest of the components are connected.
⚠️ Warning: When assembly, make sure that the antenna cable does not fall under the screws of the frame. Puncture of the cable insulation will lead to complete lack of communication.
The final step is to check the pinpoints, which are in contact with the force, but without the pressure that can damage the plastic, and then turn on the device and check the signal level.
Influence of the body and accessories on the signal
Often the problem is not the breakdown, but the external intervention. Metallized cases or magnetic-clasp cases can shield the signal, especially if they overlap the areas of antenna inserts. In the Xiaomi Redmi Note 9 Pro, the antenna zones are located in the upper and lower parts of the ends.
If you use a wide black-framed protective glass, it can also partially overlap sensors and antenna areas close to the edges of the display. Removing the case often helps to instantly improve reception for 1-2 divisions.
- 📱 Thick rubber covers weaken the signal less than metal ones.
- 📱 Magnets in car holders can disrupt the compass and GPS.
- 📱 The gold or silver coating on the case works like a Faraday screen.
And there's also the deformation of the body, which is that if the phone fell, the plastic frame could crack, and the antenna plume could move away from the contact area, and visual inspection of the internal components is a must.
Programmatic methods for improving admission
It doesn't always require physical intervention. Sometimes a radio malfunction can be fixed software-based. The first step is always to reset the network settings, and it won't delete your photos or contacts, but it will return the standard connection settings.
Go to Settings → About Phone → MIUI version and click on the version number several times to activate the developer menu. Then in the advanced settings you can find options for resetting or forced network type selection. Try setting your preferred LTE only or 3G/2G network type to check the connection stability.
Another effective method is modem flashing, but it is a complex procedure that requires an unlocked bootloader and the use of a QPST or Mi Flash utility. It is safer for the average user to do a full Hard Reset by saving a backup beforehand.
If after resetting the settings and replacement SIM-The problem persists, and the engineering menu shows an extremely low signal level, the probability of hardware failure of the antenna or the radio chip itself is more than 90%.