- An old mobile phone can act as a WiFi repeater or 4G/5G router to improve coverage in areas with poor signal.
- Configuring the hotspot correctly (name, password, security, and 2,4 or 5 GHz band) is essential to achieving a stable and secure network.
- This method is free and very flexible, but it has limitations in range, battery life, and lack of simultaneous dual-band capability.
- In large homes or homes with many devices, it may be necessary to combine recycled mobile phones with repeaters or dedicated WiFi mesh systems.
Far from being a makeshift trick, using recycled smartphones as repeaters can be a very practical solution for large apartments, multi-story houses, or homes with many walls. However, it's important to understand the limitations, advantages, and disadvantages of this method, and to know when it's worthwhile and when it's better to invest in a dedicated Wi-Fi repeater or mesh system.
What does it mean to use a mobile phone as a repeater or home mesh point?
When you turn a phone into a repeater, what you're actually doing is having the phone receive an internet connection and then rebroadcast its own Wi-Fi network, which other devices can then connect to. This incoming connection can be the router's wireless network, a wired Ethernet connection via a USB adapter, or, if you prefer, mobile data using a separate SIM card.
From a functional standpoint, the smartphone acts as an access point or hotspot : it connects to the main network (WiFi or wired) and creates its own wireless network with a name and password. It's not a "pure" mesh system like those in commercial kits, which coordinate several nodes together, but when properly positioned, it allows for a tiered coverage that closely resembles that concept.
It's important to keep in mind that phones aren't designed as professional network equipment, so their transmission power, antenna type, and configuration options are more limited. Even so, for covering specific dead zones (an interior room, an upstairs office, or a remote smart home area), they often offer more versatility than you might think.
In many cases, simply bringing your mobile phone closer to the room with poor signal, connecting it to the router's WiFi, and sharing that connection is enough to achieve a noticeable improvement in stability and speed compared to connecting directly to the router from a distance.
First, check if you really need a homemade "mesh".
Before you start enabling recycled mobile phones, it's a good idea to check some basic aspects of your current network to avoid creating an unnecessary setup. Often, coverage problems can be solved with one or two well-made adjustments to the main router, without needing to resort to makeshift repeaters or spending more money.
The first thing to do is make sure the router's physical location is reasonable: ideally, it should be in a central area, as close as possible to the rooms where you usually connect, and avoid placing it behind furniture, the TV, or against many walls. Any extra obstacles will weaken the signal at the far ends of the house.
It's also a very good idea to check that your router's firmware is updated to the latest version . Many manufacturers fix performance, security, and Wi-Fi stability issues with these updates, and you'll notice the difference in range and speed without changing any other settings.
Another key aspect is checking for unauthorized devices connected to your Wi-Fi . With network analysis apps or programs, you can see how many devices are connected and detect if a neighbor is using your connection. If there are unwanted guests, it's normal for the network to become congested, resulting in reduced range and slower speeds.
Finally, it's worth considering whether the router provided by your internet service provider is sufficient. A very cheap or old router may have very limited coverage , so even if you add repeaters, the bottleneck will still be with it. In these cases, investing in a decent router usually makes a much bigger difference than filling your house with mediocre repeaters.
How to use an old smartphone as a WiFi repeater
Once you've reviewed the above, if your problem is clearly coverage in specific areas, you can start building your own "mini mesh" using recycled phones. The most common scenario is using an old phone as a Wi-Fi repeater to extend the signal closer to a TV, PC, game console, or smart plug.
On many Android models, the trick is to use the Wi-Fi hotspot or sharing option while the phone is simultaneously connected to the router via Wi-Fi or Ethernet. In other words, the device connects to your wireless network or local Ethernet network and then creates a new network that replicates that connection.
For maximum stability, the best option is to connect your phone to the router using a USB-to-Ethernet adapter . This way, the phone receives internet via cable, without interference or signal loss, and the only "sensitive" part is the Wi-Fi it broadcasts to other devices.
If running a cable to the location where you want to place the phone isn't feasible, you'll have to connect it to the router via Wi-Fi. Distance, walls, and the quality of the phone itself greatly affect this: if the smartphone is very old or only supports older standards, the available speed will be lower and the connection more prone to interruptions.
Almost any modern phone allows you to create a hotspot, so in practice compatibility is rarely an issue . What varies from model to model is the antenna power, band support (2,4 GHz, 5 GHz, or even 6 GHz), and compatibility with protocols like WiFi 5 or WiFi 6, which make a significant difference in performance.
Basic steps to set up your mobile hotspot
Regardless of the brand or custom interface, the steps for sharing Wi-Fi from a smartphone follow a very similar pattern. The key is to properly configure the name, password, security settings, and frequency band so that your makeshift network is secure, fast, and relatively stable.
On Android, you'll usually need to go to Settings > Connections > Wi-Fi hotspot or Mobile hotspot (the exact name varies depending on the manufacturer). There you'll find the option to activate the hotspot and a menu to adjust the parameters of the network broadcast by your phone.
On iPhones, all current models include the Personal Hotspot feature, accessible from the Cellular or Personal Hotspot settings . Apple has simplified the interface considerably, but you can also edit the network name and password, and take advantage of compatibility with the latest security versions.
The most important fields you should touch are the following: the WiFi network name (SSID) that the phone will generate, the access password and the encryption type (usually WPA2-Personal, WPA2/WPA3-Personal or WPA3-Personal, depending on what your mobile and your devices support).
Furthermore, many modern devices allow you to choose whether to broadcast the network on the 2,4 GHz or 5 GHz band , limit data usage, hide the SSID so it's not visible during scanning, or even enable advanced features like Wi-Fi 6 and protected management frames. It's worth exploring the menu because, in the latest models, the customization options are surprisingly extensive.
Choose between 2,4 GHz and 5 GHz when sharing the network
Choosing the right frequency band is key to ensuring your mobile hotspot performs well. While some mid-range and high-end phones support multiple bands, they can only broadcast the hotspot on one at a time , so you won't have simultaneous dual-band operation like many routers.
The 2,4 GHz band has the great advantage that the signal reaches further and penetrates walls better , although at the cost of offering lower speeds and suffering much more interference from other neighboring networks and devices such as microwaves or Bluetooth devices.
Therefore, if the devices you want to connect are simple home automation appliances, Wi-Fi bulbs, or older equipment that doesn't support 5 GHz, you'll usually have to opt for 2,4 GHz to ensure compatibility . It's also the safest option if the mobile device and the clients will be some distance apart.
The 5 GHz band, on the other hand, offers significantly higher speeds and a more stable experience, precisely because there are fewer networks and less noise in that part of the spectrum. However, it is more sensitive to distance and obstacles, so it performs best when all devices are close together.
Since the usual practice when setting up this type of homemade repeater is to place the mobile phone very close to the TV, laptop, or computer you want to improve the connection for, it's generally best to use the 5 GHz band, provided the devices are compatible . Many users end up using it by default and only switch back to 2,4 GHz in specific cases.
Shared network security: passwords and encryption
Another point you shouldn't overlook is security. When you activate the hotspot, you're creating a new Wi-Fi network, and if you don't secure it properly, anyone nearby could connect , hog your bandwidth, or even use up your mobile data if you're using a SIM card.
The bare minimum is to set a strong password that combines uppercase and lowercase letters, numbers, and, if possible, a symbol. Even if you're tempted to use a simple password "for friends," it's important not to leave it completely open, because you'd be giving away your connection to the whole neighborhood.
Regarding encryption, current mobile phones typically offer WPA2-Personal as the standard option , and newer models offer the possibility of using WPA3-Personal or a mixed WPA2/WPA3 mode. Ideally, you should choose WPA3 when all your devices support it, as it provides an extra layer of protection against brute-force attacks.
If you need to connect older devices, you'll probably have to stick with WPA2 to avoid compatibility issues. What you should absolutely avoid is leaving the network unencrypted or with ridiculously simple keys , because you risk turning the shared network into a sieve.
Some systems also include options such as automatically turning off the hotspot when no devices are connected, or power-saving modes to prevent your phone from broadcasting unnecessarily. Configuring these features properly helps minimize power consumption and security risks when you're not using the repeater.
Use a SIM card and share mobile data
Besides extending the router's signal, a very interesting use for a recycled smartphone is to use it as a 4G/5G router with a separate SIM card . This is especially useful for providing internet access to smart home devices or other equipment located far from the router, in areas where even an intermediate repeater doesn't provide good coverage.
The idea here is to buy a dedicated SIM card, get a data plan (with or without limits), and put it in your old phone. The phone will connect to the internet via the mobile network , and you'll share that connection via Wi-Fi with nearby devices.
Since these devices are like smart plugs, sensors, or IP cameras, their data usage is usually low (except for high-resolution cameras), so you don't need a huge amount of data on your plan. A modest plan is usually enough to keep them running smoothly.
This method is also very useful when you travel abroad and get an eSIM with data from a carrier that allows tethering. You configure your phone with that eSIM, activate the hotspot, and provide a connection to your laptop, tablet, or other phones without having to insert a physical SIM card into each device.
However, if you choose this method as a more or less permanent solution, it's a good idea to keep an eye on your monthly data usage to avoid surprises on your bill. Multiple devices connected continuously can consume more data than you might think, and it might be more cost-effective to get a second landline or a dedicated Wi-Fi system.
Real advantages of using recycled mobile phones as WiFi nodes
The biggest advantage of this solution is clearly the cost. If you have an old phone gathering dust in a drawer, you can turn it into a functional WiFi repeater for free , making it ideal for vacation homes, second residences, or occasional situations where you don't want to invest in additional hardware.
Another great advantage is that setup is very simple : just go to the sharing settings, choose the type of network you want to share (WiFi or mobile data), enter a name and password, and turn on the switch. You don't need advanced networking knowledge or to struggle with complicated router menus.
The system is also incredibly flexible: you can turn the "repeater" on and off in seconds from your phone's quick settings panel. This is very convenient if you only need to extend the signal at specific times (for example, to stream a movie from a distant room).
Compatibility also works in your favor. Although mobile phones don't usually offer simultaneous dual-band or very advanced quality of service options, any device with WiFi (another mobile phone, a laptop, a Smart TV, or even more unusual devices) can connect to the network emitted by the smartphone without much trouble.
Even from an ecological point of view, giving a second life to an old terminal as part of a homemade mesh setup makes sense: you prevent it from ending up in the trash immediately and reduce the need to buy more electronics just to cover a couple of tricky rooms.
Limitations and problems to consider
It's not all advantages, and it's important to consider the weaknesses of this system before using it as a permanent solution. The first has to do with the phone's battery : if you're going to have it running as a repeater 24/7, you'll need to keep it plugged in continuously.
When a mobile phone is always plugged in and the battery is near 100% charged, wear and tear accelerates and, over time, it degrades much more quickly. Since we're talking about an old device that you no longer use daily, it's not usually a major issue, but it's not advisable to do this with your main phone if you want it to last for years.
Another critical point is the coverage that the smartphone itself can offer . Because it has very small antennas designed for portable use, the signal range will be significantly less than that of a repeater or a professional mesh Wi-Fi system. In many cases, you'll have to hold your phone quite close to the device you want to connect.
The lack of simultaneous dual-band support is another limitation to consider. Phones can typically connect or transmit on 2,4 GHz, 5 GHz, or 6 GHz (the most modern ones), but they don't handle multiple bands at once like many home routers do. This reduces network versatility if you have a wide variety of devices.
If you choose to share mobile data, your data usage can skyrocket before you know it, especially if you connect a computer or Smart TV that does a lot of streaming or downloading. Without an unlimited plan, it's easy to exceed your monthly allowance, resulting in extra charges or reduced speeds.
Finally, since it's a makeshift system, you run the risk that a phone restart, an update, or a momentary glitch could render your "homemade mesh node" unusable. It's not as robust as equipment specifically designed to run 24/7 , so it's best considered more of a temporary fix or flexible solution than a permanent infrastructure.
When is it advisable to switch to repeaters or dedicated WiFi mesh systems?
While repurposed phones offer plenty of options, there are situations where investing in a quality repeater or a complete mesh Wi-Fi system makes more sense. If you want to provide good coverage for a large, multi-story home with many connected devices and heavy use of streaming and online gaming, the ideal solution is to have equipment capable of handling high loads.
Modern repeaters with WiFi 6 and Gigabit Ethernet ports are designed precisely for this: to extend the router's signal at the highest possible speed and allow symmetrical 1 Gbps wired connections for TVs, PCs or consoles, something a smartphone can hardly match.
Specialized brands offer amplifiers and mesh systems that coordinate multiple nodes to create a single WiFi network throughout the house , with seamless roaming: you move from room to room and your phone switches access points without you noticing. In a setup using recycled phones, this transition isn't as smooth or intelligent.
If you decide to buy a repeater, it's important not to go for the cheapest option without considering its features. A very low-end device can become overloaded as soon as several users or smart home devices are connected simultaneously, causing latency spikes and dropouts that ruin the user experience.
Whichever solution you choose, the placement of the repeaters or mesh nodes is crucial: they need to receive a reasonably good signal from the router and then amplify it. If you place them too far away, they'll only repeat an already weak signal, and the result will be disappointing. The same applies to repurposed mobile phones you use as makeshift nodes.
To summarize, setting up something similar to a mesh WiFi system using recycled smartphones is perfectly viable for improving coverage in certain problem areas of the house, provided you accept its limitations and combine it, if necessary, with quality repeaters or routers. Repurposing an old mobile phone as a 4G/5G repeater or router can get you out of a tight spot, strengthen your home network, and breathe new life into a device that would otherwise be gathering dust in a drawer.
