The adoption of 5G technology has many positive and negative consequences, but there is one that has had little attention so far despite warnings from scientists.
The World Meteorological Organization (WMO) estimates that the 5G signal could cause interference in the information recorded by meteorological satellites. This would affect the reliability of weather forecasts.
According to experts, the 5G signal will occupy low frequency bands in the radio spectrum. But in parallel, they also occupy high frequencies, to improve network capacity and speed.
One of them is the 24 GHz band, which is very close to the space that meteorologists use to study water vapor particles, from which they extract key data to predict the weather.
At the World Radiocommunication Conference of 2019, representatives of 160 nations reached a global agreement to associate frequency bands with different services.
Regarding 5G, the focus of the discussions, it was agreed that it would use the 24 GHz band, but the amount of noise the signals should make was limited.
According to the International Telecommunications Union (ICU), this noise is thus prevented from causing interference in the observation of meteorological satellites.
Disagreement about the Interference of 5G
The World Meteorological Organization (WMO) has another opinion on the matter. In a statement, he noted that approved noise rates can cause 10 times more interference than this organization recommended.
“This decision has the potential to significantly degrade the accuracy of the information collected in this frequency band, which may compromise the operation of satellite observation systems for all weather forecasts,” said WMO. The band assigned to 5G is a neighbor of that used by meteorologists.
While meteorologists measure in the 23 GHz band, there is a part of the emitted radio frequency that is transferred to the lower or upper band.
Meteorologists are then concerned that their satellite measurements will be affected to some extent, or at some point, by interference from the adjacent frequency band, assigned to 5G networks.
Water vapor molecules are studied through satellites, whose signal is only emitted in the band adjacent to 5G. These data are used to know the situation in areas where there are no other sources of information, such as the oceans.
The water vapor molecules absorb electromagnetic radiation and emit it. The resonance frequency of these molecules emits at the frequency of 23 GHz, and with the use of sensors, meteorologists can know what the temperature and humidity are at that point.
No problem with 5G frequencies?
The distance between the top of those frequencies, in which the water vapor emits slight radiation and that are used in meteorology is 23.8 GHz. The bottom of the band that will be occupied by 5G is 24 and 25 GHz and will not cause any interference, say some experts.
“To get an idea, the whole part of digital terrestrial television occupies less than 450 MHz, which is a very considerable distance,” they say. They point out that with a good design and construction of telecommunications systems there should be no interference problems.
This position is contrasted with another opinion. The problem is not in the actual emission of the 5G signal, which will travel through its corresponding band, but in the noise that signal can generate.
When you send a certain signal, if the circuits were ideal, none of the power you send would go outside the pre-established band, but there may be residual noise that comes out of that band because current systems are not perfect.
This noise is common in radio communications transmissions. It is what causes, for example, that in the old transistors that tuned to the wheel, or in car radios, a station is heard at frequencies that are not exactly theirs.
This is the problem that the conference in Egypt wanted to resolve, where it has been agreed that out-of-band noise must have a maximum value of -33dDW, the unit used to measure the power of the signals.
Meteorologists demanded greater guarantees and highlight the risks of not having adjusted predictions: not preventing extreme weather events or inaccuracy in advance when monitoring climate change.
Some scientists agree that detailed studies will be needed to know how 5G affects the attenuation rate established in the conference as the desirable one. In the case of interference, they summarize the consequences: There may be two effects.
1. The signal is wrong, but the sensors consider it as true, or
2. The signal is so wrong that their own filters eliminate it.
In the first case, meteorologists would have bad data, and in the second case, they would have fewer data.
For their part, telecommunications engineers warn that these restrictions make devices more expensive. Lowering 3 dB in out-of-band noise implies greater technical complexity, which inherently entails a considerable increase in the cost of the devices, from the base station to the terminal.
It is also a matter of manufacturing. Setting unnecessarily strict limits could lead to the assumption that technically it is not possible to manufacture such devices, or even that the entire system cannot work.
Nevertheless, the limits are already set, both for the manufacture of devices and for the knowledge of meteorologists, who say that their efforts will now go towards adaptation.