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THE NEXT GENERATION of wireless technology, 5G, nudges up against high-frequency bands that are essential to weather forecasting. 5G power levels, if not appropriately limited, could compromise weather satellite measurements of water vapor, rain, snow, and atmospheric temperatures.

According to AAAS Science, August 9, 2019, 5G’s 100-fold increase in data speed could be accompanied by a 30-percent degradation in weather forecasting to 1980s’ levels.

This and the following graphic from AAAS Science, August 9, 2019.

23.8 GHz—a Critical Frequency. In “Forecasters Fear Threat of 5G Wireless Roleout,” Science writer Gabriel Popkin says, “At about 23.8 GHz, water vapor molecules emit a small amount of radiation—one of the best ways to remotely sense the atmospheric water content that fuels clouds and storms.”

A Radio Clash. Some high-frequency bands intended for next-generation 5G wireless are close to bands used to monitor faint but critical atmospheric signals.

Graphic: N. Desai/Science; data: ITU/Eric Allaix.

One of the new bands dedicated to 5G is between 24.25 and 25.25 GHz. Popkin notes, “Even through 5G transmissions will be separated from the water vapor band by a 250-megahertz (MHz) buffer, forecasters worry they will bleed into the band and swamp the faint natural emissions.”

Who’s for What? U.S. government agencies disagree over acceptable strengths of 5G frequencies. NASA and NOAA (the National Oceanic and Atmospheric Administration) are on the side of the forecasters. Backed by the White House, the FCC (Federal Communications Commission) says fears are overblown.

International agencies such as the Inter-American Telecommunication Commission (CITEL), another representing Europe, and the World Meteorological Organization (WMO) meet regularly to hash out these differences, especially with regard to limiting signal strength.

The World Meteorological Organization, based in Geneva, is an agency of the United Nations.

Measuring Signal Strength. The unit of signal strength is the decibel-watt (dBW); the closer its value is to 0, the stronger the signal. That is, a -20 dBW signal is stronger than one of -21 dBW (since -20 is closer to 0 than -21) .

Signal strength limitations of 5G being discussed range from the FCC’s -20 dBW, the likely U.S. proposal of -28 dBW, NASA/NOAA’s -42 dBW, and the WMO’s -55 dBW. Because the dBW scale is logarithmic, these numerical differences are significant: For example, Science’s Popkin explains that the NASA/NOAA’s -42 dBW “represents a limit more than 100 times stricter than FCC’s.”

It’s Ain’t Over…. Despite NASA and NOAA’s request to postpone auctioning the 24-GHz band, the FCC went ahead with it in March 2019. Both T-Mobile and AT&T bought portions of it.

The Inter-American Telecommunication Commission met last week in Ottawa. Its next meeting is scheduled for September 30-October 4, 2019, in Asunción, Paraguay.

The quadrennial World Radiocommunication Conference will start on October 28, 2019, in Sharm El-Skheikh, Egypt; one important task, to negotiate a global 5G limit.

French Meteorologist Eric Allaix heads the WMO committee on radio frequency coordination. He tells Popkin that U.S. atmospheric conditions are critical for European forecasts two to three days later. It’s “really a worldwide issue,” he says, “Our satellites need to be protected everywhere around the world.” ds

© Dennis Simanaitis,, 2019

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