Why is there a potential problem in the United States, but not Europe? It comes down to technical details.
Mobile phone companies in the United States are rolling out 5G service in a spectrum of radio waves with frequencies between 3.7 and 3.98 GHz. The companies paid the US government $81 billion in 2021 for the right to use those frequencies, known as the C-Band. But in Europe, 5G services use the slower 3.4 to 3.8 GHz range of spectrum. The aviation industry is worried that US 5G service is too close to the spectrum used by radar altimeters, which is between 4.2 and 4.4 GHz. Europe does not face the same risk, according to the industry, because there is a much larger buffer between the spectrum used by radar altimeters and 5G.
There are other differences in how 5G is being rolled out, according to the US Federal Aviation Administration (FAA). Other countries are using lower power levels, restricting the placement of 5G antennas near airfields and requiring them to be tilted downward to limit potential interference with aircraft. In France — cited by telecom carriers such as AT&T and Verizon as an example of 5G and aviation working seamlessly together — the height of a 5G antenna and the power of its signal determine how close it is allowed to a runway and the flight path of an aircraft, according to a technical note from France’s National Frequency Agency (ANFR). Antennas around 17 major French airports are also required to be tilted away from flight paths to minimize the risk of interference, the agency’s director of spectrum planning and international affairs, Eric Fournier, told CNN.