Translation by DeepL:

Europe will require router and wifi access point manufacturers to prevent the installation of firmwares or change of country to bypass the DFS protection that prevents wifi from interfering with weather radars. New rules governing the use of the 5GHz wifi band also limit the power of in-car wifi and allow drones to use 4 channels.

## The 5GHz wifi band is increasingly under scrutiny

At the beginning of the year, Europe introduced some changes in the rules that regulate how the 5 GHz band1 is used in the old continent, which is intensively used together with the 2.4 GHz band for wifi in homes and offices. This band has 19 wifi channels with many "buts" that make that for practical purposes we can not enjoy them in full.

Some channels allow more transmission power than others, which gives them better coverage. Others must use mechanisms to minimize the radiated power. Some channels can only be used in open spaces. In many of them, their use is not guaranteed since the standard requires the router to abandon them when there is a risk of interfering with radiolocation systems.

The DFS (Dynamic Frequency Selection) mechanism, mandatory in Europe, is responsible for the router taking more than a minute to start up, for the wifi being cut off from time to time if you live near an airport, military base or weather station, and even for your router not allowing you to choose certain channels.

The router, governed by the software that the manufacturer has recorded in its firmware, is in charge of managing these details that the user normally does not worry about. Since in other continents the regulations are different from those we have in Europe, some of these limitations can be avoided by simply modifying the country for which it is configured. There are also free firmwares that allow you to configure advanced parameters and disable DFS, broadcast with more power than allowed or access illegal wifi channels in Spain.

The EU wants to stop this practice, which is damaging essential services such as weather radars. One only needs to take a look at the latest reflectivity map of a regional AEMET radar such as the one in Valencia to see how interference is seriously affecting its readings.

The modification of the CNAF that the Ministry of Digital Transformation is finalizing will rectify the UN-128 that regulates the 5GHz band to adapt it to the instructions coming from Europe. One of the novelties is for manufacturers of wifi routers and access points, which will not be able to allow the change of country to one that does not require DFS protection, such as Russia or India. The other new feature may have an even greater impact, as manufacturers will be forced to prevent the installation of firmwares that allow DFS to be disabled.

<< The user shall not have access to the settings (in hardware or software) of the WAS/RLANs related to the DFS if changing those settings would cause the WAS/RLANs to no longer meet the DFS requirements. This includes: a) not allowing the user to change the country from which they are operating or the frequency band of operation if that would cause the equipment to no longer meet DFS requirements, and b) not accepting software or firmware that would cause the equipment to no longer meet DFS requirements. >>

Some router operating systems such as Mikrotik's RouserOS allowed altering the DFS behavior with the dfs-mode option, which no longer exists in the current version. OpenWrt is a popular open source operating system based on Linux, compatible with many models of home routers that when installed allows you to control the wifi parameters in detail without limitations.

## Drones will be able to use wifi channels

The new regulation of the 5GHz band also brings some changes on the use of these frequencies indoors, outdoors and in vehicles. Thus, the first 4 channels of the band, which could only be used indoors, may be used outdoors as long as it is not a fixed installation, which excludes their use for point-to-point links. They may also be used in train carriages and road vehicles, but with a power limit of 40 mW.

These 4 channels are the ones that host the most wifi networks in urban environments, but they will have a new tenant, since they will also be able to be used by drones, which until now were forbidden in this band.