That’s because a lot of routers don’t support wireless bridging and, even if they do, you may need two routers from the same manufacturer (or even two identical routers) to make them talk to each other without connecting them together using a network cable. If you’re lucky, your routers will both support WDS, but in a lot of cases your current and spare routers won’t work nicely with each other.

Unless your home is already wired with Ethernet ports, trailing a long cable from your main router to the spare in a different room is going to be unsightly and unpopular with everyone else who lives with you. You could use a pair of  powerline network adapters, but this will cost you a fair bit if you don’t already have some.

When we originally wrote this guide a few years back mesh Wi-Fi systems had only just begun to appear. With prices starting from around £70/$80, it makes a lot more sense to invest in one of these kits than to save that money and fiddle around with old routers which are likely to be slower and not support the latest Wi-Fi standards.

If that’s not an option for you and you want to have a go at using your spare router to increase Wi-Fi coverage beyond the reach of your current router, then we’ll explain how to go about it.

It’s usually best if your spare router supports bridge mode. This effectively turns it into a simple Wi-Fi access point which allows your other router to do all the work (such as routing and dishing out IP addresses). If it doesn’t support bridge mode, you can try following the steps below, but there are still no guarantees that it will work as you want it to.

If it doesn’t work and you still don’t to shell out for a mesh system, a lower-cost alternative is to buy a range extender such as Netgear’s EX3700, which costs around £30/$30.

1. Find your router’s IP address

First you need to find out some details about the router you’re currently using, including which Wi-Fi channel it is broadcasting on and what security type it is using.

On any Windows PC connected to that router, open a command prompt (enter cmd in the search box) and type ipconfig.

This will show your gateway and the computer’s IP address.  Note down your gateway as this is the address of your primary router usually in the format; 192.168.1.1 or similar. Ignore the longer addresses with letters (if you see them): these are IPv6 addresses and you need only the IPv4 address.

For more detailed instructions, here’s how to connect to your router.

2. Connect to the router

Next open a web browser and, in the address bar, type the gateway IP address you’ve noted and hit Enter.  You should see a set up screen for your primary router.  It may ask for a user name and password.  If you know these details, enter them.  If not, the information may be on a label underneath the router, or the information may be available by searching the internet for the default user names and passwords for your router model.

Once you’ve accessed the router’s configuration screen you will see something similar to this.

3. Check your Wi-Fi settings

As you’ll see there are lots of settings you can access and change, but you don’t want to reconfigure the primary router, only check its settings. Have a look at the wireless settings and find the details for the Wi-Fi network name, the channel and the security type.

This router’s SSID is BT-Hub6-ZG2C, is working on channel 11 (for 2.4GHz) and channel 36 for 5GHz, and uses WPA2 for security. The SSID is the name you find when searching for wireless networks from your laptop, tablet or smartphone.

Note: Some routers including this BT one, change Wi-Fi channels automatically for the best performance. That’s indicated by the ‘smart’ here, and you may want to turn off that feature so that both routers will always use a different channel (to avoid interference).

Make a note of the security type because you’ll need to set the second router to the same setting. When you have finished there is usually a ‘log out’ option. You have only looked at the settings and made no changes, so there is nothing to save, if asked.

4. Reset the router to factory settings

Plug in the old router and reset it to its factory settings. Find a small hole at the back of the router, usually marked ‘reset’.

With the router powered on, insert a paper clip or similar, and hold in for a few seconds. When you release the paper clip you should see all the lights on the router go out and come back on again.  You have reset the router to its factory settings.

If this doesn’t work for your particular router, look up the reset procedure online.

5. Configure your second router

Connect this second router now, with a network cable, to a PC or laptop which is not connected to the first router. The best way to do this is to turn off your main router for a few minutes while you set up this slave router, to prevent the PC connecting via Wi-Fi.

Once attached to the second router, go through step 1 again with this router until you get to the stage where you have accessed the configuration page. Here, we’re using a D-Link router.

6. Copy over the settings

Ignore any setup wizards, and go to the Wi-Fi settings page. Enable wireless, change the wireless network name to be the same as the primary router and choose a channel well away from channel 6, which is what the primary router is using.

Match the security type exactly and type in the same password you use for Wi-Fi on your primary router.

7. Give it a fixed IP address

Finally you need to make the slave router work alongside the primary router and not against it. Essentially you need to turn of the NAT function so you don’t end up with double NAT, and you need to give the second router an IP address in the same range as the first.

This is best done by putting the second router in bridge mode, but if that’s not available you can try the following:

Head to the LAN setup page (or similar) and give the router an IP address in the same range as the IP addresses given out by my main router, but outside of the range that is automatically assigned by DHCP.

Dynamic Host Communications Protocol is the process by which a device issues IP addresses to equipment on the network. You need to stop the slave router giving out IP addresses to devices, leaving that task in the hands of the primary router. 

Disable DHCP by un-ticking it on the relevant configuration page. To assign a fixed IP address, let’s assume the main router has an address of 192.168.1.1 and that it’s setup to to issue addresses – by DHCP – between 192.168.1.2 and 192.168.1.49. Give the slave router an IP address of 192.168.1.50. Remember this address as you might need it to access this router later.

On each configuration page, confirm your choices by clicking ‘save settings’ at the bottom of each page as you go. Remember, too, that once you’ve change the router’s IP address you will have to wait for it to reboot, and then access it by typing the new IP address into your browser’s address bar.

8. Connect it all together

Now you are ready to connect it all together. If your two routers support WDS or wireless bridging, be sure to enable that on both (see the next section).

The other way is to connect the two routers together with a long network cable or a pair of powerline networking adapters.

These work by using the mains power cables in your walls and floors to act as network cables as well as passing electricity through them. They work only on ring mains which are all connected back to a single consumer unit (fuse box). If you have two separate buildings or an extension which has its own electricity supply and meter, then powerline adapters aren’t going to work.

We’ve explained separately how to set up powerline networking adapters to get your adapters connected.

With both routers now turned on, it’s time to test your network. Take a smartphone, tablet or laptop, and check to see the signal strength when close to each of the routers. You will find that you have successfully extended the reach of your wireless network and now have a second wireless access point.

9. Or go wireless

If you’re lucky or you chose well when you bought your old router it might already have the features necessary to be reused to improve Wi-Fi coverage. Without needing network cables, or powerline adaptors, that is.

We can’t list all the routers that have some sort of bridge or repeater mode, but all the usual suspects (including Apple, Belkin, Linksys, Netgear and TRENDNet) have the functionality in most of their recent products. One feature to look out for is WDS (Wireless Distribution System).

The nomenclature vendors’ use differs, but the basic steps for setting up are quite similar. In a nutshell, the key steps are finding the bridge or repeater mode in the configuration tool, choose it, and then enter whatever network information the tool asks for. That could be a MAC address, network name (SSID), spectrum band and security mode, for example.

It’s important to note that this functionality isn’t standard, so there is no guarantee routers from different vendors will work together.

10. Using custom firmware

For routers that don’t have built-in WDS (or similar) you might be able to install custom firmware such as DD-WRT, OpenWRT or Tomato. To use them takes some technical knowledge and the ability to follow instructions very closely.

For example, installing DD-WRT on a router in most cases is almost as simple as installing a program onto your computer. However, doing it incorrectly can leave you with a router that you have to throw away. So follow the instructions carefully!

Your router has to be compatible with DD-WRT, OpenWRT or Tomato and you’ll have to search online for your specific router model to find out if a custom firmware can be installed. Once compatibility has been established, there is plenty of information, including precautions, for each manufacturer and router on how to install the firmware.

Once that’s done, turning on the repeater function is fairly straightforward. You will find more information on the DD-WRT website.