How To Set Up a 4G Backup Network for Home and Office

How To Set Up a 4G Backup Network for Home and Office

5 Mar 2021 | 13 min read

Quick Summary

We walk you through the hardware you'll need to set up a cellular backup network so you never lose connectivity again.


Whether you’re a business for whom it’s mission-critical that network uptime stands at 100% 24/7, or a home user tired of putting up with the buffering circle on your Saturday night Netflix sessions, a cellular backup network can help you. When your ISP fails at the most inconvenient times, it’s possible to leverage the power of 4G and LTE to keep the wheels turning. Here’s what you’ll need to set up just such a backup network of your own.

The 4G Antenna

The first device you’ll need for your 4G backup network is a 4G antenna. Even though routers are often shipped with antennas, the purpose of a backup network is to provide a reliable connection when you need it most and that requires a high-quality signal.

When it comes to antennas, the difference between a quality, dedicated antenna that you’ve gone to the effort of mounting properly, versus the bunny ears included with your router, is like the difference between fibre optic and copper cable for your broadband. The former is the newer, more advanced infrastructure and supplies your home with superior speeds. It’s the same with an antenna; lower quality means of pulling signal into your home will result in a less stable, less reliable connection and therefore a spotty user experience.

We have a dedicated article to help you with choosing the best antenna for your fixed wireless access application. We recommend Poynting antennas and, since we’re using this for fixed wireless access, both directional and omnidirectional antennas can be used. Please refer to the aforementioned article for details on the correct application for each.

Leverage the power of the cellular network to never lose connectivity at the office or at home again.

The 4G Router or 4G Modem

The next device you’ll need for your 4G backup network is a 4G modem. 4G modems are available both as standalone units that you connect to a compatible router or as a built-in function on a 4G router. Like your ISP-provided ‘home hub’, this will be your home’s in-point for connectivity. With your 4G modem, however, you’ll be pulling internet connectivity from the cellular network, rather than through the cable infrastructure to your building.

As with cabled internet, you’ll need to choose a provider. For the greatest possible signal strength and, therefore, performance (see the next section on picking a 4G antenna), you’ll want to check which providers offer coverage from your local cell masts. If you only have one or two masts to choose from and you’re with the Three network in the UK, but Three doesn’t utilise either of the masts you have access to, you obviously won’t get very far.

With a provider and a modem, you’ll put your SIM card (yep, just like your smartphone, you’ll use a SIM card to connect to the cellular network for your home connection) directly into the 4G modem (if you have a 4G router instead of a separate router and 4G modem, you’ll put the SIM card directly into the router). You’ll pay for your plan monthly just like a phone bill and unlimited data-only SIMs can be found online or in-store for very reasonable monthly prices.

You’ll want to choose either a monthly plan that gives you money back for your unused data, or a pay as you go plan. Since this is a backup network, we’re not planning on using it all the time. For this reason, it could be useful to crunch the numbers to see how many hours you project having to use the 4G network before your wired internet comes back online and calculating how much data you’ll use in that time to help you find the best plan.


Frustrated with unstable, unreliable internet service from your ISP? Use a 4G backup network to maximise network uptime.

What’s The Difference Between a 4G Modem and Router?

If you’re confused about the difference between a 4G router and a 4G modem, a 4G modem will only modulate and demodulate the signal (see below), while a 4G router will be able to do this as well as all the usual functions of a router. A 4G modem will need to be connected to a dedicated router which will take care of routing network traffic around your local network and back out to the wider internet. Both functions are essential on any network. 4G routers can do both, but 4G modems will be useful if you already have a quality router and just want to add 4G functionality to it.

Modulation and Demodulation

A 4G modem translates an analogue signal in the form of a radio wave into ones and zeros that can be interpreted by computers. It also converts messages made up of ones and zeros being sent out to the wider internet back into an analogue radio wave signal. It’s these radio wave signals that your 4G antenna is receiving and transmitting.

A traditional modem will do the same but will convert light signals (in the case of fibre optic) or electronic signals (in the case of copper cable) into ones and zeros.

What to Look For From A 4G Router

Dual SMA Inputs

For best signal strength and reliability, you’ll want to choose an antenna with MIMO (multi input multi output) capabilities. Such units actually contain multiple antennas within a single housing and each antenna needs its own cable and input. This means you’ll want to choose a 4G router with enough SMA connectors for the antenna you’ve chosen. A 2x2 MIMO antenna, for example, will call for a 4G router with two available SMA connectors. Some 4G routers will have an SMA connector designed for a WiFi antenna labelled ‘wireless’ or ‘wifi’ to communicate with clients on the network. This isn’t what you want, so make sure you identify that the SMA connectors on your router are labelled ‘cellular’, ‘mobile’ or similar..

Dual SIM

Some 4G routers offer dual-SIM support, meaning there’s room for two SIM cards within the unit. This will provide a built-in failsafe in case you lose connection to your primary carrier. If you’re building this 4G network backup for your home or office because you want to guarantee you always have a connection, this third layer of security might be appealing to

Management Capabilities

If you’re a network installer or an individual looking to install 4G routers at multiple locations, you might want to manage all of your networks from a single, central source. A network management platform like Teltonika’s RMS (remote management system) will do the trick here. Home users looking to set up a single backup network won’t need this. Business owners looking to set up a network at the office might benefit from using such a remote management system so that an IT admin can quickly troubleshoot any issues remotely at short notice.

VDSL and 4G LTE Combo Routers

Some routers combine VDSL and LTE support and so are capable of modemming for both technologies, then routing that traffic throughout your local network. Such routers tend to be more expensive than their specialist counterparts, but offer a more elegant solution for those who desire one, giving users the ability to manage all aspects of both their wired and LTE connections from a single interface.

If you want your 4G network to be a true backup that takes care of itself, then a combo router is what you’ll want since you’ll want to configure the router to create a single local network that pulls connectivity from the VDSL (primary) source wherever possible but, when unavailable, pulls from the 4G SIM to use cellular data.

Having two separate routers (one for broadband, one for cellular) will result in two separate local networks. Whilst this isn’t a problem per se, you may have to switch devices over manually when your primary network fails. You also might have issues with devices automatically connecting to the 4G network when you’d prefer them to default to the broadband network first. You can usually configure a network preference hierarchy on PCs, but mobile devices and smart home devices won’t give you this much control. Having a dedicated router integrating both kinds of connection into a single network will therefore usually be the best solution.

Recommended Products

A basic 4G router like Teltonika’s RUT240 offers quick, simple configuration of the essentials, including wireless network creation. It’s limited in throughput though, its single LAN port offering just 150Mbps, so you might want to spend extra on something that can offer faster speeds. It’s limited on configuration options too, so if you want to configure QoS rules, for example, then you’ll want a 4G router that can offer that. Finally, the RUT240 is a 4G router only. It doesn’t have a built-in fibre modem, so you’ll end up with two separate local networks.

Draytek offers a wide variety of routers with advanced configuration options, including 4G + VDSL combo routers. The Draytek Vigor 2862LN, for example, offers both ADSL/VDSL ethernet routing and 3G/4G LTE with support for a single SIM card. USB ports on the device also give users the option of connecting an external 4G modem for additional redundancy if desired. With this option or a similar router, you’ll be able to have your 4G connection feed into the same local network as your fibre connection, making for the most elegant solution possible.


The Teltonika RUT240 4G Router offers simple configuration and remote management options.

Next Steps

With a 4G antenna and 4G router in place, you just need to configure your 4G router to create a WLAN that can be broadcast by your wireless access points (WAPs). You’ll do this, as usual, from the router’s web interface. Connect the router directly to your PC via ethernet cable and head to the router’s IP address from any web browser to open up the configuration. Our best advice for this step is to refer to the user guide for your router here, as you’ll need admin credentials to log in and the process for each router will be slightly different. A basic setup wizard is usually in place and the defaults will typically do just fine.

Once the WLAN is configured, you’ll want to broadcast the wireless network throughout your home or office space. Smaller spaces will only need one or two such access points. Your 4G router might be capable of acting as an access point on its own, but will be limited in range and capability compared to dedicated WAPs.

Earlier we mentioned that a 4G router that exists separately to your fibre (VDSL) router will create a separate local network. For small locations that don’t require many WAPs, this won’t be an issue. However, for very large buildings this WILL become an issue. Your WAPs can only broadcast the SSIDs from one of your routers. The 4G router will have created a different LAN to your fibre router, meaning you’ll need a second set of access points distributed throughout the space to broadcast the wireless networks for this second LAN. Conversely, the combo router will deal with both 4G and fibre together and create a single LAN, meaning you’ll only need a single set of WAPs throughout the space.

If you need to distribute your WLAN across a large area with poor ethernet availability, mesh APs will be best. If you have good ethernet outlet availability in each room, wired WAPs can be used for best results and positioned strategically throughout the space. Finally, you will of course use network switches to extend your network where required.


The Draytek 2862LN is a 4G + VDSL combo router that offers advanced configuration options for those that need them.

Closing Notes: Is A 4G Backup Network Cost-Effective?

When it comes to 4G networks, the initial cost of the hardware you’ll need to get a good end result has to be taken into consideration. Whilst unlimited data plans can be acquired for a reasonable monthly cost, your ISP likely charges you a relatively low one-time installation/setup fee. In comparison, the cost of a quality 4G antenna and router is always going to be high.

However, if you’re located in an area where 60Mbps download speeds are unattainable from any ISP, going wireless could be a great option for you and provide you with speeds you thought you’d never get.

There are also the various ‘unseen’ costs of not using a 4G backup network to consider. For example, if you conduct a business in an area with an unreliable copper connection, then the cost in lost business and the inconvenience of having to put up with a poor connection are likely to make the initial investment in 4G network hardware worthwhile.

You won’t be seeing Gigabit speeds with 4G, though, so if you’re in an urban area with great FTTP (fibre to the premises) coverage, then you’re unlikely to need a solution like this unless it’s essential to you that you have a connection at all times, in which case the couple of times a year when you have troubles with your ISP will make the 4G solution worth it.

Finally, future-proofing your solution will greatly extend the life and performance of your cellular backup network. Over the span of ten years, a couple of hundred pounds spent on quality hardware sounds very reasonable. Spending a bit more on 5G-ready hardware is therefore strongly advised.


In summary, for a 4G backup you can rely on, you’ll want a quality 4G antenna with MIMO capabilities and a 4G router with multiple SMA connectors to take advantage of the antenna’s MIMO. The router itself should offer good throughput from its LAN port and all of the configuration options you desire. If you don’t know what you need, the basics should be good enough.

For the most elegant solution, especially for buildings where you want to broadcast the wireless network across a large area, you’ll want to choose a VDSL + 4G combo router, or pick up a 4G modem and connect it to your existing router (so long as it accepts connections to external modems).

Finally, to greatly extend the life and performance of your 4G network, it’s worth picking up 5G-ready hardware where possible. At this point in time, that really just comes down to the antenna, so pair a 5G-ready Poynting antenna with a quality combo router from Draytek or a similarly respected manufacturer and you’re well on your way to a superb cellular LTE 4G backup network for your home or office.

How To Set Up a 4G Backup Network for Home and Office