Recently, NOAA — along with the Department of Commerce, which oversees NOAA, and NASA — warned that the FCC’s decision to allocate spectrum in the 24 GHz band to 5G carriers will imperil weather forecasting. The crux of NOAA’s concern is that new 5G users will operate too close to spectrum (23.8 GHz) that meteorologists rely on to detect water vapor in the atmosphere. Interference from 5G signals, they say, could potentially reduce the accuracy of weather forecasts, leaving Americans with less time to respond to approaching storms, tornadoes, or other natural disasters.
It certainly sounds bad, but NOAA’s doomsday predictions are devoid of scientific justification. When federal agencies raised interference concerns in 2017, the evidence they presented was ultimately withdrawnafter its methodological shortcomings were exposed. NOAA’s current claims are based on a similarly flawed study, which has not been released publicly, that doesn’t take into account how 5G networks work in the real world. For instance, it fails to consider that 5G — unlike 4G — will use beamforming to precisely transmit signals to a particular user and prevent out-of-band emissions. In addition, the 5G spectrum will be more than 250 MHz away from the passive weather sensors NOAA is concerned about, providing further protection from interference.
Amazingly, the weather sensor on which NOAA’s claims are based, known as the conical microwave imager/sounder (CMIS), was scrappedin 2006. That’s right: The equipment that supposedly needs protection from 5G interference doesn’t even exist. The CMIS was replaced by the Advanced Technology Microwave Sounder (ATMS), which uses a smaller and wider beam width that is much less susceptible to nearby 5G interference.
In fact, NOAA currently operates with the same interference rules for its spectrum neighbors as those the FCC has adopted for 5G carriers in the 24 GHz band, and there are no allegations of interference to weather sensors today. For example, 40,000 fixed and microwave links already operate in the band just below 23.8 GHz without any reported interference issues, according to FCC Chairman Ajit Pai.
It’s also unclear why NOAA didn’t raise these concerns earlier, instead of attempting to derail a long-planned process at the 11th hour. The FCC’s 24 GHz auction, which wrapped up earlier this month, has been in the works for five years, giving government agencies — and anyone else with credible evidence — ample time to object to the FCC’s plan. Yet during all this time, NOAA remained silent.
If the FCC caves to NOAA demands and imposes tighter emissions standards on 24 GHz operators, those airwaves could become unusable for domestic 5G services. Other spectrum bands used by weather forecasters, like the 36-37 GHz and 50 GHz bands, will likely also be targeted for stricter regulations, further impeding 5G’s rollout.
Making last-minute changes to interference regulations would undermine the confidence of mobile carriers who’ve already spent billions of dollars acquiring the rights to these airwaves and send a chilling message to other commercial users that their terms of service can be changed outside the normal regulatory process.
The debate over 24 GHz also threatens to disrupt a crucial multi-national conference this fall, where global limits for the 24 GHz band and other 5G bands will be set. The FCC has already taken a position on making the 24 GHz band available to 5G carriers, as well as rules to mitigate interference. Changing the U.S. position on 24 GHz now would undermine our ability to advocate that the band be open to 5G globally.
The U.S. government should be united in pushing to reallocate underutilized spectrum to its highest and best use. Mobile carriers are clamoring for more spectrum as they race to provide 5G services to their customers, and the 24 GHz band is an important step toward that goal.
The FCC shouldn’t be swayed by NOAA’s alarmism; your 7-day weather forecast will be fine.
Liam Sigaud works on economic policy and research for the American Consumer Institute, a nonprofit educational and research organization.
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