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A recent view of water vapor forming a rare “bomb cyclone” over the United States, captured by one of the National Oceanic and Atmospheric Administration’s geostationary satellites.

National Oceanic and Atmospheric Administration

Lawmakers seek delay of radio spectrum auction for next-gen cell service, saying 5G plans could hurt weather satellite data

Update, 15 March: Overriding concerns from NASA, NOAA, and Congress, the FCC went ahead with its 5G spectrum auction on Thursday, 14 March. Bids after the first day totaled more than $300 million.

Here is our initial story:

A bipartisan group of lawmakers today asked the U.S. Federal Communications Commission (FCC) in Washington, D.C., to delay an auction of a wireless spectrum scheduled for tomorrow to be used for future 5G service. FCC is ignoring scientific evidence that the radio spectrum being put up on the block could interfere with crucial measurements collected by weather satellites, the lawmakers say.

In a letter sent to FCC Chairman Ajit Pai, U.S. Representative Eddie Bernice Johnson (D–TX) and Representative Frank Lucas (R–OK), the chair and ranking member, respectively, of the House of Representatives’s science committee, say communications traffic in one segment of the spectrum that FCC is putting up for auction could compromise the satellites’ ability to track water vapor from space. Such water vapor measures are essential to predicting future rainfall, tracing hurricanes, and monitoring sea ice. Thanks to its intrinsic physical properties, water vapor cannot be tracked at other frequencies.

“Any interferences with this channel would therefore seriously impact public safety,” Johnson and Lucas write.

Similar concerns were raised separately in recent weeks by NASA, the National Oceanic and Atmospheric Administration (NOAA), and the Department of Defense. Johnson and Lucas voice concern “that the FCC appears to be dismissing the views and concerns of” those agencies, “the National Academy of Sciences, and the international community.”

In late February, NASA Administrator Jim Bridenstine and Commerce Secretary Wilbur Ross, who oversees NOAA, asked FCC to withdraw proposed operating guidance for the spectrum because, they said, it would allow too much electromagnetic chatter on the radio band in question, between 24.25 and 25.25 gigahertz (GHz), that might interfere with the weather data collection. (Water vapor is measured on the nearby 23.6- to 24-GHz band.) A joint NASA/NOAA study had suggested that any noise should be limited to –50 decibel watts (dBW); the Europeans, for example, recently defined their noise threshold at –56 dBW. The FCC auction, however, would allow –20 dBW of noise, a significantly higher level, especially given its measure on a logarithmic scale.

On 8 March, however, Pai rejected NASA and NOAA’s request and stated his intent to proceed with the auction. The Department of State, which served as an arbiter between the agencies, previously sided with FCC in the fight. Whether Congress’s late engagement in the dispute will change FCC’s calculations remains to be seen.