Passive Science Interests Stress Importance of Protections in 24 GHz Band

The National Academy of Sciences’ Committee on Radio Frequencies (CORF) stressed the importance of protection for passive scientific use of the 24 GHz band, in comments responding to an NPRM commissioners approved 3-2 in December, over dissents by Commissioners Brendan Carr and Nathan Simington (see 2312260043). The NPRM seeks to align rules for the band with decisions made at the World Radiocommunication Conference in 2019. Comments were filed this week in docket 21-186. “Observations made by Earth Exploration Satellite Service sensors provide unique data regarding the state of the Earth System, and especially its atmosphere at a given moment in time, which, by their very nature, cannot be reproduced or replicated,” CORF said: “The observation frequencies cannot be modified, because they are largely determined by the physical characteristics of what needs to be observed, for example, specific water vapor lines are the result of the molecular properties of water.” The IEEE Geoscience and Remote Sensing Society also stressed the importance of controlling potential levels of contamination from out-of-band-emissions to passive operations in the band. AT&T said the FCC should implement Resolution 750, which the WRC adopted. “The leadership of the United States at WRC-19 resulted in limits that will fully protect passive operations in the 23.6-24.0 GHz band from unwanted emissions from [upper microwave flexible use service] networks in the 24.25-27.5 GHz bands, without unnecessary measures that would impact the roll-out of 5G mobile services,” AT&T said. GuRu Wireless, which is developing a system for wireless power transfer at a distance in the band, counseled caution. “While ostensibly limited in scope to the adoption of the WRC-19 decision, the NPRM here seeks comment on additional issues, such as the adoption of emission limits that are more stringent than the Resolution 750 limits,” GuRu said: “The Commission should avoid regulatory overreach and not expand its initial proposal by making any modifications to emission limits unrelated to UMFUS operations.”