Nextivity Cel-Fi Roam R41 review

Nextivity CEL-FI Roam R41 review: boosting mobile coverage

100% human

Can you boost the signal if you have trouble receiving mobile phone coverage? Chances are, if you live in a major city and only travel on major highways, you can always make a call. The mobile coverage can be very patchy if you live in the country or travelling the big lap of Australia. This review of the Nextivity CEL-FI Roam R41 will help you understand whether this solution is viable for improving coverage.

CEL-FI Roam R41 review

Where is Mobile Phone coverage available in Australia?

Telstra proudly quotes that they have 99.5% of Australia’s population mobile phone coverage. However, by land mass, this equals 2.7 million square kilometres. Australia’s land mass is 7.7 million kilometres, so Telstra has 35% coverage by land area.

Telstra mobile coverage
Telstra Coverage Feb 24.

Compare this with Optus and Vodaphone, which cover approximately 22% of the Australian land mass.

A typical mobile phone can communicate with a base station or cell tower up to 15km away. With the right equipment, this can be increased to 80km.

A mobile phone can make a triple-0 emergency call on any available network, irrespective of which provider you are with. Still, if there is no cell tower in range, there is no coverage, and the only way to call for help would be via satellite communication.

How can I improve mobile coverage?

If you want to improve your mobile coverage, there are several things you can do:

  • Install a mobile phone repeater like the CEL-FI Roam R41
  • Ensure your phone is at the highest point and not blocked by obstructions. For example, a mobile phone at window height in your car will have much better coverage than one sitting in a cupholder blocked by steel doors.
  • Attach a high-gain external antenna to your phone or mobile router, assuming it has an external antenna point.
  • Change mobile phones. Some mobiles have better antennas than others and thus work better in remote areas.
  • Change mobile phone providers. Telstra has the best coverage in Australia. Boost Mobile benefits from having 100% Telstra coverage with better value plans. Other Telstra resellers (MVNOs), such as Woolworths, have reduced coverage.
  • Wi-Fi calling. If you can access the internet via Wi-Fi, assuming your phone and plan support Wi-Fi calling, your voice call will be carried over the internet and will not rely on mobile coverage.
  • Note an SMS text may succeed where a voice connection cannot be made. Also, a voice call may succeed where a data connection might not.

What is a mobile coverage repeater?

Mobile phone repeaters are radio devices that retransmit a mobile signal to improve the reliability of mobile coverage.

How does mobile booster work

The first question to answer is whether a CEL-FI device boosts or amplifies the signal. Mobile carriers strictly control repeaters in all countries, and Australia is no exception. This is because unauthorised use can interfere with the operation of their networks. A mobile phone “booster” wired directly to a single mobile phone is illegal in Australia.

A repeater works by having a high-gain antenna that receives a mobile signal. This antenna has a better chance of receiving the signal than your phone’s antenna. It is designed to maximise the reception and transmission of signals. The type, quality and positioning of the antenna will make a difference.

A CEL-FI repeater then amplifies the signal by up to 100dBm. It retransmits those signals wirelessly to your mobile phone via a small antenna.

Nextivity distributes three models of RFI repeaters in Australia:

The R41 is designed for moving vehicles or boats and supports repeating one 3, 4 or 5G channel. The R41 amplifies the signal, enabling you to use your phone further from a phone tower where, without the R41, you could not use your phone.

The G41 and G51 models are both stationary units for use in buildings. They both support repeating two channels with the G51, allowing the support of 5G frequencies. These stationary units also allow you to use your smartphone further from the CEL-FI, i.e. better indoor coverage.

The G models having two channels will support high data speeds but cannot be used on the move.

Increasing the distance from a mobile cell tower relies on many factors, including the carriers’ settings. Theoretically, a call could be made up to 100km from a base station in perfect conditions.

What are the CEL-FI R41 features?

The CEL-FI Roam R41 is a plug-and-play 5G mobile phone repeater designed to improve coverage for users in vehicles and boats.

cel-fi roam r41 pack
R41 contents with omnidirectional 7.5dBi gain antenna.

The R41 replaces the CEL-FI G31. The improvements include support for 5G signals, more frequency bands used by the carriers and the ability for the same unit to switch between the different carriers in Australia. The Roam R41 uses the 4th-generation chip, which improves the unit’s performance, especially in vehicles, to reduce interference (isolation) from the two antennas.

The R41 helps solve poor coverage, improving your ability to call, text and use the internet.

RFI sells the R41 in several configurations with your choice of antenna options. The main unit runs off a supplied 12-volt cigarette lighter power lead, measures 17 x 8 x 4.5 cm and weighs 0.5kg. The internal antenna is quite small and is mounted horizontally. The range of this antenna (to which your mobile connects) is up to 30m.

cel-fi roam r41 low profile antenna
R41 with a low-profile antenna.

Antenna choice will depend on the application. You would choose a marine antenna (6.5dBi gain) if used on a boat. There is a low-profile (2dBi gain) antenna and various mobile omnidirectional antennas (up to 7.5dBi gain) designed for vehicle mounting. The antenna has a critical role in that different antennas will offer different levels of antenna gain. The higher the antenna gain, the better the performance (assuming flat terrain).

Although not required for daily operation, the WAVE App must be used to select and register your product with your mobile carrier (no fees). This app provides the ability to upgrade software, change carriers, monitor performance, etc.

RFI CEL-FI Roam R41 specifications

Bands  3G, 4G and 5G
Dimensions17 x 8 x 4.5 cm
Price (RRP)From $1,299
System Gain100 dBm max
Warranty2 years

Using the CEL-Fi R41

Setting up the R41 involves mounting the external antenna. Many will mount this on their bull bar, but we chose to mount ours on the roof rack with an RFI folding bracket. Maximising the distance between the external and internal antennas is important to reduce interference. Installation can easily be done yourself or arranged by an RFI dealer.

Wave App

Once the unit is powered up and the WAVE app is loaded and set up, the R41 is pretty much set and forget. If it is powered, it is working! I measured its power usage at around 7 watts an hour. A second app, “MyWave”, synchronises the channel that the phone and CEL-FI use to ensure maximum benefit of the CEL-FI to the user. It will force the CEL-FI to change to the channel the phone is using. This app works better on Android.

An LED light on the unit will flash green if a network cannot be found and will be solid when operating and providing coverage.

Living in Sydney, I had to drive into the valleys of the Watagans on the central coast to locate an area with poor coverage. Once we lost signal on our mobiles, we powered the R41 and were back online.

Does a mobile repeater improve mobile data?

Today, we use mobiles more for the internet than we make voice calls, so we set up a test. We created three scenarios using an Oppo smartphone, a Netgear M6 Pro and an R41 to test download speeds. We found a location with very poor mobile coverage. The phone did not work in the car but did out of the car. All tests were done using the Telstra network via a SIM provided by Boost Mobile.

Cel-Fi antenna
DeviceDownload speedUpload speed
Oppo Find X23.16 Mbps0.2 Mbps
Oppo Find X2 connected to R416.1 Mbps1.4 Mbps
Netgear M6 Pro with external dual channel RFI high gain directional Antenna19.6 Mbps10.5 Mbps

The R41 can only use one channel, the Oppo phone and the M6 can use six channels and the M6 connected to the directional antenna can use two channels. More channels, if you can get reception, means more speed.

For the technical folk: The R41 operates as a SISO (single-input-single-output) unit, thus only using one channel, whereas the mobile and modem use MIMO (multiple-input-multiple-output) and potentially carrier aggregation, which improves the data rate.

The net result is the R41 doubled the data performance of the phone. However, the M6 Pro with a high-gain antenna, able to use two channels versus one, tripled the performance again.

Hi-gain directional antenna
A high-gain directional antenna connected to Netgear M6 Pro.

This test is certainly not of a CSIRO standard. Still, if you wanted the best speed and were stationary with a directional antenna, you could get a better result. However, doubling data performance is a welcome time saver if you do 100km/h down a highway using the CEL-FI extender. Also note that some remote cell towers have very slow internet connections; thus, no matter how close and what gear you had, it would not improve performance. Many people using the same cell tower also have the same effect, with everyone having to share the available bandwidth.

Who is the CEL-FI Roam R41 for?

The CEL-FI will help with poor coverage and extend your communication ability if you live, holiday or work remotely. Thousands of mobile repeaters have been sold in Australia. The new CEL-FI Roam R41 improves performance and allows you to change the carrier without changing the hardware. This product is not for city dwellers, but if you want peace of mind when travelling country roads or waterways, then this product will mean you can stay in touch and call for help in more places.

The only way to further improve communication is to look at more expensive satellite solutions. Plenty is happening in this space, and GadgetGuy will bring you any news that changes this equation.

GadgetGuy occasionally uses affiliate links and may receive a small commission from purchased products.

Value for money
Ease of use
Amplifies mobile coverage
Make phone calls in a boat or vehicle where you couldn't before
Supports multiple carriers inc 5G
Single channel limits data speeds
Still limited to cell tower availability