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Mobile phone accessories Reviews
15,670 Reviews

Nextivity Cel-Fi RS2 review

£450 inc VAT

Manufacturer: Frequency Telecom Ltd

Our Rating: We rate this 3.5 out of 5

Answering the call for better 3G mobile reception indoors is the Nextivity Cel-Fi RS2, which lets you relay a weak mobile data signal around the home or office.

Those who live in good 3G reception areas, mainly in the larger conurbations, are the lucky ones. They can have the web on their phones, download apps, browse sites and do all the other things that high-speed internet connections offer. 

Others of us are less fortunate. If you live in an area of only passable signal strength, you may have to consider radical measures, like the Nextivitiy Cel-Fi RS2 to get your mobile going.

Setup is theoretically extremely easy. The larger of the two devices, the small speaker-sized Window Unit, sits on a window sill where you have a usable signal, while the Coverage Unit, about the size of a wireless router, lives at a point in the house or office where you need to improve the signal. Both have simple mains power blocks and require no other connection, talking to each other through a 5GHz wireless link.

These Nextivitiy Cel-Fi RS2 units only work with 3G – they won’t improve a regular 2G, GPRS signal, so won’t help you with simple voice calls, where coverage is marginal. 

If you can get some 3G signal within a building, though, the Nextivitiy Cel-Fi RS2 units should be able to boost it from a single bar to five bars, by retransmitting it. Currently, Cel-Fi only works with Orange/T-Mobile and O2 services.

There are one or two problems with the setup and use of the kit. The front panel of the Window unit has a power LED and five signal strength LEDs, but these are not high brightness devices. Since you have to fit it in a window, where there’s a lot of light coming in, even on a winter’s day in Devon, it makes it difficult to see the lights when trying to position it.

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The Coverage unit is likely to be further into the building, so LED intensity isn’t a problem. Here, though, it’s the single seven-segment display which is awkward, as it’s used to display a range of arcane status and error codes, only some of which are explained in the Setup Guide. 

Although in other respects, the guide is exemplary, it didn’t mention what the E5 error we had during set-up was. Fortunately, it gave way to the ‘8’ which meant it was working properly. 

We tried the Nextivitiy Cel-Fi RS2 unit in a convenient cottage on Dartmoor, where one-bar 3G service is the best on offer; and that only from one point, on one upstairs window sill. 

After placing the Window Unit there the Coverage unit downstairs in the hall gave good, full strength coverage in most rooms downstairs – even though some of the walls are feet thick.  

Benefits include faster web access and downloads and longer battery life, as phones aren’t straining to make connection all the time.

The Nextivitiy Cel-Fi RS2 pretty much does what it sets out to do, but at a price. The units cost £450 a pair, which is a lot for a small business and even more for a home installation. 

You’ve got to be sure there’s no other solution just round the corner, like an imminent new mobile mast in your area, before digging deep into your pocket.

Nextivity Cel-Fi RS2 Expert Verdict »

3G signal transceiver and relay unit
support for 3GPP Rel. 8 features
5GHz link compliant with ETSI EN301 893 V1.5.1
up to 100dB path loss between units (approx 20m between WU and CU
max EIRP: 14.7dBm (max 3 carriers) downlink to 25.7dBm (max three carriers) uplink
up to 100dB system gain
2 x 12V DC power supplies
Window Unit: 207 x 144 x 144mm
Coverage Unit: 151 x 149 x 49mm
  • Build Quality: We give this item 8 of 10 for build quality
  • Features: We give this item 6 of 10 for features
  • Value for Money: We give this item 6 of 10 for value for money
  • Performance: We give this item 8 of 10 for performance
  • Overall: We give this item 7 of 10 overall

This is a very simple, plug-and-play solution to getting 3G coverage throughout a building which has sketchy signal strength. It’s pretty easy to use, though the display LEDs could be brighter. The main problem is the price: £450 is a great deal to spend on mobile coverage – phone line broadband and a wireless router is likely to be a lot cheaper.

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