Asserting “a substantial stake” in the outcome of the proceeding, the ARRL has commented in opposition to an FCC proposal that would leave licensed radio service users vulnerable to interference from unlicensed devices. In a docket unrelated to Amateur Radio spectrum, the Commission has indicated that it’s willing to consider adding licensed Globalstar terrestrial users to the 2473-2483.5 MHz band — already shared by licensed and unlicensed services — with the condition that customer handset users in the new allocation accept interference from unlicensed radio services now legally operating there. The League’s comments were in response to a Notice of Proposed Rule Making (NPRM) in IB Docket 13-213 and RM-11-685.

“This plan would for the first time create a multiple-use, radio frequency environment in which Part 15 unlicensed devices do not have to protect a licensed, allocated radio service from harmful interference,” the ARRL stressed. “This is untenable as a precedent, and it makes the entirety of the [NPRM] likewise untenable.”

The League said allowing Globalstar to deploy Ancillary Terrestrial Component (ATC) users of its Mobile-Satellite Service (MSS) system under technical rules that apply to unlicensed users would depart from long-standing rules protecting licensed radio services from interference resulting from the use of unlicensed Part 15 or Part 18 ISM devices.

The League said the proposal “represents an unprecedented withdrawal of the assurances that licensed users have been given by the Commission and relied upon in dozens of allocation proceedings.” The League said many Commission orders “consistently embody” the principle that Part 15 device operators must cease operations that cause harmful interference.

“The Commission cannot, consistent with the entire regulatory underpinning for allowing Part 15 devices, premise an allocation decision in this case on the unique provision that a component of a licensed radio service will not be entitled to interference protection from Part 15 devices, whether those unlicensed devices are incumbent or deployed in the future in the band at issue,” the League concluded.

The ARRL suggested that the FCC “do some bona fide technical evaluation” of compatibility between and among services in and below the band at question and ATC systems before deciding whether or not the proposed overlay is compatible.

“The price of making the wrong assumptions is too high in this and similar allocations proceedings,” the ARRL said, “and the damage from the wrong assumptions will be, practically speaking, impossible to reverse.” The Commission, the League continued, “must absolutely refrain from compromising” the basic concept that unlicensed Part 15 devices may only operate “on the absolute condition that they do not interfere with any component of a licensed radio service.”

The League’s comments further pointed out that the reason Part 15 wireless broadband devices operate below 2473 MHz has been to provide a sort of “guard band” to protect MSS above 2483.5 MHz. Globalstar contended that Part 15 wireless devices were not being deployed in the segment it wants, but, the ARRL noted, that unlicensed users avoided the segment in the first place for Globalstar’s benefit.