While the deployment of 5G is taking place gradually — as of December 1, nearly 31,000 5G sites have been authorized by the National Frequency Agency (ANFR) in mainland France, of which around 21,000 are declared technically operational — some areas are still little or badly covered by the network today. For those affected, using a 4G/5G extender can solve these connection issues.
As the name suggests, the purpose of a 4G/5G booster (or repeater) is to boost the mobile network signal to enable better reception; concretely, it picks up the transmitted signal and multiplies it. The device obviously requires that the signal exists and is therefore useless in the white zone. Such a device consists of a receiving antenna - to be positioned where the signal is maximum, oriented towards the nearest cell tower - an amplifier and an internal antenna, which will relay the amplified signal.
Before acquiring an amplifier, it is important to find out about the frequencies used by its operator. In France, 5G is currently deployed on several frequency bands:those used for 2G, 3G and 4G networks (“low” bands) – at 700 MHz, 800 MHz, 900 MHz, 1.8 GHz, 2.1 GHz and 2.6 GHz — and two new bands, at 3.5 GHz and 26 GHz. Lower frequencies have a longer range and cut through obstacles better, while higher frequencies handle more traffic.
4G/5G boosters are easily found on the internet. It should be noted that if the use of such a device is not illegal, it nevertheless requires the authorization of the operator(s) concerned. Using an amplifier without this agreement is an offence, subject to a criminal penalty of up to six months in prison and a fine of €30,000. A misconfigured amplifier can indeed disrupt surrounding frequencies, much like a network jammer; however, the relay antennas are able to detect this type of interference and the operator immediately refers to the ANFR.
The ANFR reports that it is frequently called upon (nearly 150 interventions per year) to resolve interference in mobile networks caused by repeaters installed without authorization. The agency also recalls that as radio equipment, the amplifier must comply with European Directive 2014/53/EU of April 16, 2014, known as RED, and therefore bear a CE marking. Note that the ANFR's Cartoradio.fr site — which lists all the antennas transmitting at more than 5 watts declared on French territory — allows you to see which operators operate the various authorized sites, as well as the location and the orientation of the nearest relay antenna in the geographical area of your choice.
For the most curious and do-it-yourselfers among you, know that there are nevertheless online tutorials allowing you to make your homemade 4G amplifier, which you can try to reproduce if only out of simple scientific curiosity and for extremely brief use. The given link, which proposes to make an amplifier using two cans of coffee, is inspired by a video proposed by Popular Science , and is intended for holders of a GSM (2G) telephone; the connection part is therefore to be adapted to current smartphones, but the procedure remains valid.
If you want to know the strength of the mobile signal picked up by your phone, you can consult the settings of the latter:for an Android smartphone, go to the section About the phone> Status> Network (signal strength is indicated in dBm); for an iPhone, the procedure is a little different. This is a negative number and the closer it is to zero, the better the connection to the 4G/5G network. Typically, a signal around -40dBm is great, while a signal around -120dBm is very bad.
The choice of the amplifier will be essentially guided by the type of network and frequencies that one wishes to amplify. Note that each model can extend the signal by one or more frequencies (this is called a dual-band, tri-band, quad-band amplifier, etc.). The prices obviously vary according to these capacities (count 150 to 200 euros minimum for a good amplifier).
The choice of the signal reception antenna, which should be installed on the roof or on the facade of the building concerned, is also important:in urban areas, experts recommend using an omnidirectional antenna (there are usually more antennas, so the signal can come from several directions); in rural areas, a monodirectional antenna can be more effective, on the condition that it is oriented in the direction band. Ideally, the coaxial cable that connects the receiving antenna to the amplifier should be as short as possible (to limit losses); care must also be taken not to twist or wrap this cable to guarantee the best possible reception.
Although expensive and strictly regulated, the use of a 4G / 5G amplifier can be a good solution for people in areas with poor network coverage. Note that its use also makes it possible to reduce the power of the waves emitted by telephones (which is on average 250 mW maximum at 900 MHz):the power of the signal emitted by an amplifier is of the order of 10 mW to the maximum and its proximity requires much less power to connect to it.
