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Support and FAQs

Need to contact us directly? If your question has not been answered in the FAQs below, click here to get in touch.

General

What is Cel-Fi and how does Cel-Fi Work?

Cel-Fi is a smart repeater designed to improve the indoor mobile phone signal for 3G and 4G users. Due to its unique intelligent features, Cel-Fi is the only user-installable legal mobile phone repeater permitted in the UK. Cel-Fi consists of two units: the Network Unit (NU), and the Coverage Unit (CU). Users place the NU in an area with the strongest signal from the mobile network. The CU is then either placed in the centre of the home or office, or in the area where the best signal quality is most needed. The two units communicate wirelessly with one another enabling the CU to effectively produce a 'bubble of quality signal' throughout the home or office, resulting in significantly better voice quality and greater data throughput. The WU and the CU are placed at varying distances apart, but in general an indoor distance of up to 20-30 metres is common.

Does Cel-Fi boost mobile phone signal indoors?

Yes. Cel-Fi’s mobile signal booster is specifically designed to improve indoor signal for between 20 and 30 metre radius within the building, making it ideal for homes and SME businesses.

Is Cel-Fi Legal?

Yes Cel-Fi is legal. Currently in the UK Cel-Fi operates within the conditions of the mobile network spectrum licenses awarded by the UK government and enforced by Ofcom. Cel-Fi devices have been approved by certain networks. In the UK (and several other countries) Cel-Fi devices are ultimately under the control of the mobile networks, i.e. the network has the ability to disable Cel-Fi devices in a particular area, without any user input. (Ofcom is currently consulting on making devices such as Cel-Fi completely license-exempt (like mobile phones), but that is not yet part of UK law.)


Mobile operators have historically adopted an extremely strict policy against the use of user-installed mobile phone signal repeaters and boosters on their networks as they caused interferen ce and damage to the performance of the networks. It is for this reason that Ofcom consider many mobile signal repeaters as illegal. Due to its unique intelligent features, Cel-Fi is the only user-installable legal mobile phone repeater permitted in the UK.

What is a mobile signal repeater and is it legal to use one?

A mobile signal repeater is a radio device that works to boost mobile network coverage for users. They amplify frequencies from mobile network providers via reception antennas. All radio devices must meet regulations set out by Ofcom. These mobile phone signal repeaters are commonly known for interfering with mobile providers and as a result, Ofcom does not licence any signal repeater in the UK, making them an illegal technology.


Cel-Fi’s technology is more advanced, allowing mobile network providers the ability to monitor and regulate the use of Cel-Fi units themselves. For this reason, they classify as a Smart repeater and are considered a legal mobile phone repeater in the UK.

What is the difference between a mobile signal repeater and a Wi-Fi signal repeater?

Wi-Fi signal repeaters (or boosters) are used to extend the coverage of your Wi-Fi signal in buildings that have weak Wi-Fi connection. Commonly, these are used for home users and can increase the coverage of Wi-Fi within a building to areas that are not necessarily covered by original wireless router. Wi-Fi repeaters work by using built-in wireless routers to boost the current router transmission and amplify it.

Mobile signal repeaters such as Cel-Fi, work specifically to boost 3G and 4G data and voice coverage indoors for specific mobile networks. They focus specifically on improving voice clarity and reduce dropped calls for mobiles in areas with poor network coverage, as well as increasing download speeds and improving streaming and internet browsing on mobile broadband enabled devices.

Cel-Fi has the ability to turn one bar of signal into up to 5 bars and can amplify 3G and 4G from areas in a building with stronger coverage, to other areas that have little or no coverage within a 13,000 square foot radius - ideal for businesses as well as home use. Unlike Wi-Fi boosters, Cel-Fi does not require a broadband connection.

What is the difference between Cel-Fi and traditional analogue boosters?

The most powerful conventional analogue boosters provide gains of about 70dB - compared to Cel-Fi's 100dB gain. The 30dB gain difference corresponds to 1,000 times higher gain from Cel-Fi. All this gain is obtained from Cel-Fi digital core: since Cel-Fi reconstructs the signal obtained by the Window Unit, it is able to rebroadcast a clean signal, as if it was coming from the Operator carrier, at full power.

Differences of gain Cel-Fi signal booster Traditional analogue booster
Gains in dB 100dB (or 1,000 times the most powerful conventional boosters (70dB)) Most boosters: 60dB. The more expensive boosters provide up to 70dB, or 1,000 less gain than Cel-Fi
Coverage Up to 13,000 sqft Most boosters: 3,000 to 6,500 sqft. The more expensive boosters that provide up to 10,000 sqft need complex indoor antenna installation.
What is the difference between the Cel-Fi PRO, DUO and PRIME models?

Cel-Fi UK currently has three models available for purchase; the Cel-Fi PRO, the Cel-Fi PRIME and the Cel-Fi DUO. All 3 work to boost indoor mobile signal for home and office use.

The PRO is designed to dramatically improve voice and data coverage in up to four bands for 3G, 4G and LTE. The box is compact and has a screen that allows the user to monitor the programming. The PRO has a 13,000 square foot coverage making it perfect for small to medium businesses.

The Cel-Fi DUO works in the same way but offers coverage in up to 2 bands. It also has a 13,000 square foot coverage and is recommended for homes and small businesses.

The PRIME is also available in up to 2 bands offering coverage of 1-2 rooms (approximately 1,000 square foot) making it perfect for dense urban areas, apartments and high rises.

In all other respects, the three models are the same. They are locked to a particular network, only boost that network’s radio frequencies and implement hardware and software algorithms that completely protect the network from the harmful effects usually associated with repeater products.

What technologies does Cel-Fi support?

All signal boosters are carrier approved to support 3G and 4G voice and data.

What's the radiation level of Cel-Fi units?

So are the Cel-FI Signal boosters safe? We actually test the Cel-Fi units like a phone for a SAR rating. Anything with a SAR rating of less than 2.0 is defined as 'touch safe'. Both the Cel-fi window unit and coverage unit have a SAR rating below 2.0.

Technically measuring SAR is usually only done for hand-held or body worn devices so WiFi routers generally don't have SAR ratings. In any case the power we emit is no greater in general than other consumer wireless networking devices and smart phones.

What is the range/radius of the Cel-Fi PRIME, DUO and PRO?

The 3 Cel-Fi units offer various ranges depending on your requirements. The Prime offers a radius of 1,000 square feet which is the equivalent of 1-2 rooms. The DUO and PRO offer a radius of 13,000 square feet for larger homes or business premises.
Other factors which can affect range include:

  • The building construction
  • Strength of the signal at the Window Unit
  • Physical separation of the Window Unit and Coverage Unit (more separation = more boost)
How many devices can the Pro boost?

There is no limit to the number of devices that can be attached to the network via Cel-Fi. The number of calls the units can support depends on how far away they are from the serving base station (shown by the number of input signal bars on the display of the Cel-Fi Network Unit). Where the coverage is weak (1 or 2 bars on the Cel-Fi Network Unit) the unit may support as little as 3-6 calls. Where the coverage is good (4 or 5 bars on the Cel-Fi Window Unit) the unit can support 20 calls or more.

Do I need a Cel-Fi unit on each floor?

The amount of coverage you get with one unit differs for every building and can be influenced by a variety of different factors e.g. thickness of walls. We recommend that you start with purchasing just one Cel-Fi unit for your building and see how this works for you. If you would like to discuss your requirements in further detail, prior to purchasing, please call +44 (0)330 353 0197 to speak to one of our advisors.

Will certain materials in my building affect the unit from working correctly?

Certain building materials can affect the coverage of the unit. Older buildings tend to use more materials and have thicker walls and therefore radius coverage can be reduced. Modern construction materials such as foil-backed insulation and thermally-reflective glass can have a similar effect. If you would like to discuss a particular material in further detail with one of our advisors, please call +44 (0)330 353 0197.

How many units work together within the same radius?

Cel-Fi has tested two units working together correctly within the same radius. Cel-Fi cannot guarantee that loss of performance or network interference will not occur if more than two units are used together within the same radius.

How long is the plug lead on the units?

It measures approximately 2m in length.

How do I stop an order I've made?

We process orders very quickly via an automated process, so please contact us as soon as possible! We will do our best to stop the order or make the needed changes but please be aware that any orders already processed cannot be stopped. In this case, you would be required to follow the returns policy.

My order shipped and I want to cancel.

In the event we are unable to stop the order, we can of course offer you a return service. To request this, please submit a support request for a Return Merchandise Authorization number (RMA#) from support@cel-fi.co.uk and fill out a returns form to send back to with the unwanted order. Please note: Cel-Fi will not cover return postage costs for unwanted products. For further information visit our Returns section.

I ordered by mistake.

In the case of an incorrect order, we will gladly help you place the correct order and provide you with all the details you need to return the item that was ordered incorrectly. Please contact our customer service team as soon as you are aware of the mistake to avoid unnecessary shipping costs.

Installation

How do I install my Cel-Fi PRO unit in my home?

Watch our simple installation video for everything you need to know to install your Cel-Fi unit in your home.

How do I install my Cel-Fi PRO unit in an office?

Watch our simple installation video for everything you need to know to install your Cel-Fi unit in an office.

How do I install my Cel-Fi DUO unit in my home?

Watch our simple installation video for everything you need to know to install your Cel-Fi unit in your home.

How do I install my Cel-Fi PRIME unit in my home?

Watch our simple installation video for everything you need to know to install your Cel-Fi unit in an office.

Compatibility

What networks are compatible with Cel-Fi?

We have Cel-Fi units available for Three, EE or O2. However, within these networks there are also Mobile Virtual Network Operators. Please see the additional networks these units can support on the link:


Mobile Networks and hosted Operators (MVNO)

Please note that MVNOs may occasionally change their host network. If this happens, please contact us about reconfiguring your Cel-Fi unit. Please also note that network operators have the right to shut down your system at any time, without notice.

Does it work with other Networks that are not listed above?

Cel-Fi is authorised for use by >180 mobile operators around the world. Of the world’s top 20 mobile operators, 13 have either implemented or are testing Cel-Fi. Cel-Fi UK only sell signal boosters configured to UK based networks. Other worldwide networks are available for a range of other countries; however, if a mobile network is not offered by Cel-Fi, the network is not available for purchase.

Does a Cel-Fi system have to be activated or provisioned on in the mobile operator's network?

In the UK all cel-fi units must be registered using a mobile app available for Apple/iOS and Android mobile devices. Other networks may or may not require registration.

Does Cel-Fi require maintenance or adjustments if changes occur to the serving mobile network?

No, Cel-Fi does not require maintenance, and it will automatically adjust to changing cellular network situations.

Is Cel-Fi operator or service provider specific?

Yes. Each Cel-Fi system is customised to work on an individual operator network.

Can you reconfigure the unit’s network if you change mobile networks?

Cel-Fi units can be reconfigured by Nextivity from the network the unit is programmed to. A fee will be charged to do so. Please contact our support team (support@cel-fi.co.uk) with the serial number of your unit for more advice on reconfiguration. New Cel-Fi units can be re-configured to other networks using the Wave mobile app, if they were supplied by Cel-Fi.co.uk. Units sullied directly through the UK mobile networks cannot be reconfigured to other networks.

Does the Cel-Fi work for multiple networks?

No. Cel-Fi is configured to one network at one time. Whilst it is possible to reconfigure the network on your Cel-Fi system, you will only ever be able to boost one network at one time.

Will Cel-Fi work with my Apple Device?

Yes. All iPad and iPhone versions are supported by Cel-Fi systems sold on this web site.

Does Cel Fi work internationally?

Cel-Fi units are not only set to particular frequencies, but they are locked to the network identity (referred to as the 'PLMN-ID'). Therefore Cel-Fi devices typically only work for the particular country and network they are sold to. Only Nextivity can create the configuration for any given network.

I am living outside the UK and want to purchase from this site. Will the Cel-Fi unit work in a different country?

Cel-Fi offer various configurations for a range of EU networks. To find out if we can support you, call one of our advisors on +44 (0)330 353 0197.

Technical Information

What is IntelliBoost?

The Cel-Fi's IntelliBoost is the first processor designed specifically to optimise the indoor transmission and reception of 3G and 4G wireless signals in silicon. With advanced filtering, equalization and echo cancellation techniques, Nextivity has developed an embedded architecture which delivers unprecedented in-building data rates and pervasive 3G and 4G connectivity. The IntelliBoost processor ensures that Cel-Fi products never negatively impact the mobile network while providing maximum coverage.

What frequency is used to communicate between the two units (the Window Unit and the Coverage Unit)?

Cel-Fi Pro and Duo use channels from both the U-NII-1 (either 5.15-5.25 GHz OR 5.25-5.35GHz) and the U-NII-2 block (5.47-5.725 GHz) to communicate between the Network Unit and the Coverage Unit.

Does Cel-Fi cause significant degradation to mobile network quality as traditional repeater products often do?

Cel-Fi utilises an intelligent processor to actively adjust to the network environment. It uses multiple techniques including automatic gain control, real-time path loss analysis, and uplink signal gating to ensure that it never degrades the quality of the macro network signal or artificially raises the noise floor of the node B.

Is Cel-Fi a mobile phone signal repeater?

Mobile phone signal repeaters are classified as radio devices. They work to boost mobile phone signal, however, they can interfere with mobile operator networks and therefore are considered illegal as laid out by Ofcom.

Cel-Fi is different in that it is considered a smart repeater under the criteria set by Ofcom. A Smart Repeater is a mobile phone signal booster that is connected to a particular operator network and allows the host mobile network to control the device. Unlike, mobile phone signal repeaters, smart repeaters do not interfere with the mobile network’s coverage and are therefore considered a legal mobile signal booster.

What makes Cel-Fi different from other smart signal boosters?

Cel-Fi relies on intelligent, self-organising algorithms to maximise the area of coverage for users while ensuring that it does not compromise or interfere with mobile operator networks or impede other subscribers' signals. Cel-Fi does not require any new equipment or changes to existing network infrastructure, or mobile devices. Recognised for its superior design and effectiveness, Cel-Fi is the only consumer mobile signal booster authorised by the communications commissions in Australia and the United Kingdom, and the first consumer mobile signal booster fully compliant with the new Report and Order for signal boosters as defined by the Federal Communications Commission (FCC) in the USA, effective from March 2014. (AKA ‘FCC Part 20’).

What radio spectrum and frequency bands are used by the different Cel-Fi units?

There are many different variants of the units depending on the network provider.

  • For EE and Three, the PRO uses ‘Band 1’, ‘Band 3’ and ‘Band 20’ meaning that the radio spectrum bands are 2100MHz, 1800MHzand 800MHz. The DUO and PRIME use ‘Band 1’ and ‘Band 3’ (2100MHz and 1800MHz radio spectrum bands). This means that they will work in the vast majority of locations in the UK, but in very isolated areas, which rely on Band 20 coverage, the Duo and Prime may not work.
  • For O2 the Pro uses ‘Band 1’, ‘Band 8’ and ‘Band 20’ meaning that the radio spectrum bands are 2100MHz, 900 MHz and 800MHz.
  • For Vodafone, the PRO uses ‘Band 1’, ‘Band 7’,‘Band ‘8’ and ‘Band 20’ meaning that the radio spectrum bands are 2100MHz, 2600MHz, 900MHz, 800MHz supporting.
  • All Cel-Fi units currently available in the UK support both 3G and 4G.

Troubleshooting

I need some technical help with an error I am getting on my Cel-Fi PRO unit.

Try running the “Cel-Fi Wave” mobile app on your Apple or Android mobile device and connect to the Cel-Fi Coverage Unit using Bluetooth. The mobile app will prompt you if you need to enter registration information, and offer trouble-shooting tips.

Please download our troubleshooting support guide and follow the instructions.

Troubleshoot support for the Cel-Fi PRO Window Unit
Troubleshoot support for the Cel-Fi PRO Coverage Unit

If the issue is still not resolved after carrying out the instructions on the troubleshooting guide, please contact a member of our customer service team on +44 (0)330 353 0197 or support@cel-fi.co.uk

I need some technical help with an error I am getting on my Cel-Fi DUO unit.

Try running the “Cel-Fi Wave” mobile app on your Apple or Android mobile device and connect to the Cel-Fi Coverage Unit using Bluetooth. The mobile app will prompt you if you need to enter registration information, and offer trouble-shooting tips.

Please download our troubleshooting support guide and follow the instructions.


Troubleshoot support for the Cel-Fi DUO Unit

If the issue is still not resolved after carrying out the instructions on the troubleshooting guide, please contact a member of our customer service team on +44 (0)330 353 0197 or support@cel-fi.co.uk

I need some technical help with an error I am getting on my Cel-Fi PRIME unit.

Try running the “Cel-Fi Wave” mobile app on your Apple or Android mobile device and connect to the Cel-Fi Coverage Unit using Bluetooth. The mobile app will prompt you if you need to enter registration information, and offer trouble-shooting tips.

Please download our troubleshooting support guide and follow the instructions.


Troubleshoot support for the Cel-Fi PRIME Unit

If the issue is still not resolved after carrying out the instructions on the troubleshooting guide, please contact a member of our customer service team on +44 (0)330 353 0197 or support@cel-fi.co.uk

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