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ARRL to FCC: Amateurs and Vehicular Radars Can Play Nicely Together on 77-81 GHz


In comments filed on April 6 in response to a February FCC Notice of Proposed Rulemaking and Reconsideration Order (NPRM&RO) in ET Docket 15-26, the ARRL has told the Commission that it should make no change in the Amateur Radio allocation at 76-81 GHz and impose no additional regulatory constraints on Amateur or Amateur-Satellite uses of the band. The League said the FCC should proceed with authorizing short-range radar (SRR) systems for automotive applications in the band under Part 15 rules, and that such applications are compatible with amateur operations in the band.

In its NPRM&RO, the FCC solicited comment on issues involving expanded use of various radar applications in the 76-81 GHz band, which Amateur Radio shares with other services. The band 77.5-78 GHz is allocated to the Amateur and Amateur Satellite services on a primary basis, and to the Radio Astronomy and Space Research services on a secondary basis. The NPRM&RO was in response to a 2012 Petition for Rulemaking (RM-11666) by Robert Bosch LLC and to two petitions for reconsideration of a 2012 Report and Order (R&O) addressing vehicular radar systems in the 76-77 GHz band. ET 15-26 incorporated earlier proceedings.

In its comments, the ARRL suggested that the FCC overreached in proposing unjustifiable changes at 77-81 GHz on its own initiative.

“There is not, anywhere in the four corners of the Bosch Petition for Rule Making or in any comments that have been filed thus far in response to RM-11666, any suggestion that there is any incompatibility between Amateur Radio operation and automotive radars,” the ARRL said. “Quite the contrary.” The League said a credible, current ITU study has “definitively established” compatibility between short-range automotive radars and Amateur Radio.

The ARRL said Bosch’s filing of its Petition followed “extensive discussions and technical evaluations between ARRL and Bosch” that making spectrum at 77-81 GHz available for automotive radars “would have no significant impact on the Amateur Radio Service.” Bosch, the League pointed out, “did not propose a domestic spectrum allocation for vehicular radar devices and systems,” just modification of the FCC Part 15 rules to permit vehicular radars at 78-81 GHz on the same basis that these radars now operate in the US at 76-77 GHz — on a non-allocated, non-interference basis.

The ARRL said that no changes are necessary in the Amateur Radio domestic primary allocation at 77.5-78 GHz or in the secondary amateur allocation at 77-77.5 GHz or 78-81 GHz to accommodate automotive radar systems at 77-81 GHz. “Nor are any additional Part 97 rules necessary to accommodate compatible sharing of that band between radio amateurs and automotive radar systems,” the League added. “Indeed, that is the position of the United States in anticipation of consideration of WRC-15 agenda item 1.18 later this year.”

The League characterized as “both premature and poor spectrum management” the FCC’s proposal to unilaterally permit unspecified fixed radar systems throughout the 76-81 GHz band “without the benefit of any completed, definitive studies relative to the compatibility of fixed radar systems with automotive radar, radioastronomy and/or Amateur Radio in this band.”

Any consideration of fixed radars at 77-81 GHz, the League said, “should await the completion of conclusive, refereed compatibility studies that credibly establish compatibility with incumbent services.”

The ARRL said should there be any “unjustified displacement” of the Amateur or Amateur-Satellite services from any portion of the 76-81 GHz band, the FCC should allocate “equivalent spectrum” for those services. As possibilities, the League suggested the bands 75.5-76 GHz and 81-81.5 GHz.

The deadline for reply comments — ie, comments on filed comments — in this proceeding is April 20. The ARRL plans to file reply comments.




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