You can boost mobile phone reception at home or on the move (quick guide smartphone)

You can boost mobile phone reception at home, on the move, in a boat, caravan, etc. But it is not all that cheap or easy.

First, be aware that almost all 4/5G boosters, often marketed as signal enhancers, are entirely illegal in Australia. This is both a legal and safety issue. Unscrupulous online stores peddle these to desperate ‘signal-less’ people, who unknowingly put themselves at risk with potentially dangerous and ineffective equipment.

They are illegal for a good reason. All RF amplifiers need expensive certification before they join a Telco network. Otherwise, you can disrupt that network and impair its use for others, including military or aircraft bands. Australian 4 and 5G bands are often different to other countries.

Some are not illegal, and nine times out of ten, they are made by USA Nextivity Inc. Powertec distributes these in Australia under the brand Cel-FI through approved resellers and Telcos.

How do they work?

If you can’t get a reliable 1-2 bar signal, Cel-Fi will not work. It is called garbage signal in, garbage signal out. You can measure signal strength and bands (Android only) using the free Network Cell Info Lite and Wi-Fi. Australian bands are here.

For Apple iPhone (not tested)

Dial *3001#12345#* and press Call – This is called Field Test mode. You should be able to toggle between ‘bars’ and dBm by pressing the bars (once the code has been entered).

To find bands in use Dial *3001#12345#* and press Call. Select UMTS Cell Environment, UMTS RR Info, and Downlink Frequency. This will give you a channel number, followed by some other numbers in brackets.

The most crucial part is a suitable external antenna.

First, it must be tuned to ONE 4G LTE band/frequency that you can get, usually Band 28/700MHz Telstra/Optus/Vodafone, Band 26/850MHz Telstra, and Band 5/850MHz Vodafone. To be clear, you may need a different antenna for each Telco. These low frequencies can travel up to 15km line-of-sight from a tower. There are some dual-band antennas, but these require a dual-band Cel-Fi amplifier.

Pole-mount it as high as possible and facing the nearest tower. You can check tower locations at RFNSA. It connects to the signal booster via a Coaxial cable.

Next is the signal booster/repeater

Theoretically, it can add up to 100dB gain (the legal limit for in-home use). Say your signal was -100 to -115dBm (almost unusable); the amplifier can bring this up to -20 to -50dBm (lower is better). However, how much of that 100dB gain works depends on how clean the original signal is and may only result in a minor increase. The aim is to get close to -50dBm.

Finally, the internal antenna

This is for in-home use (wall or ceiling mount) and has a limited range so as not to interfere with neighbours’ reception.

Carrier Approval

Nextivity has a WAVE Portal and App that registers the device with a Telco (so it can connect to the network). It allows you to change Telco (usually without a hardware change) and test antenna strength.

When not to consider a 4G signal booster

When your performance expectation is too high, it won’t give you mobile coverage over a whole farm or industrial complex. That is when you call your Carrier, and they can explore mini- or micro-cells at a far greater cost.

Signal boosters are not suitable for data.

Approximate cost

A Nextivity Cel-Fi Go G51 kit for Australia, supporting one band at a time from 1/2100Mhz, 3/1800Mhz, 5/850MHz, 7/2600MHz, 28/700Mhz, or 5G n78 sub-6GHz low band (700Mhz), costs about $3600 plus fitting. You can have up to two internet Omni antennas (splitter required) or slave a second signal booster and two more antennas. Our readers say that forget it unless you can get 4G band 28 or band 26/5.

What about mobile in-car use?

Nextivity has a Roam 41 Cel-Fi for car, boat and caravan use. Prices start from $1400 (in-car) to $2,000 (caravan). You may need to spend more on an antenna that suits your vehicle (roof, bull-bar or other mounting).

CyberShack’s view – you can boost mobile phone reception but use a certified product

A quick look at eBay shows 4269 results – most totally illegal – and fines are up to $412,500 and two years in jail. If you get caught, you must surrender the device.

Use the free Network Cell Info Lite app to see if your phone can get better reception. Read Is Telstra Blue Tick accurate for rural phone reception?

If your phone does not see multiple towers at usable reception strengths, a new phone with a Qualcomm Snapdragon processor may improve things.

We recommend the lower-cost options of

OPPO A98 5G 2023 – a class leader in many ways

 Moto g84 5G – how does Motorola do it?

At the high end, the Samsung Galaxy S24 Ultra – the ultimate Android smartphone (not the S24 or S24+) is the best option, although we will soon see some Motorola premium handsets using a Qualcomm modem.