In comments filed in response to an AT&T Mobility Petition for Rule Making seeking a new air-to-ground communications system on 2.3 GHz Wireless Communications Service (WCS) spectrum, the ARRL has once again asked the FCC to elevate the Amateur Service allocation at 2300 to 2305 MHz from secondary to primary. The Petition (RM-11731) asked the Commission to authorize an LTE-based in-flight connectivity service in the WCS “C” and “D” blocks (2305-2315 MHz and 2350-2360 MHz, respectively) for airlines and airline passengers. AT&T has asserted that restrictions on out-of-band emission and power limits to protect adjacent-band users make the use of the C and D blocks problematic. The wireless provider asked the FCC for rule changes to permit deployment of its service “using currently fallow spectrum” while also “preserving adequate interference protection to users of adjacent bands.”

“Notwithstanding this broad and nebulous claim, there is no showing anywhere in the four corners of the Petition that the proposed rule changes would permit any continued Amateur Radio operations on a secondary basis in the shared A block (2305-2310 MHz),” the ARRL commented on September 22. More to the point, the League said, there is no showing in the Petition that Amateur Radio operations in the adjacent 2300-2350 MHz band would be protected from increased out-of-band emissions, if the FCC were to implement the changes requested.

The League asserted in its comments that the FCC has, to date, “failed to protect Amateur Radio operations at 2300-2305 MHz from WCS out-of-band emissions.” The ARRL said the band is “regularly and substantially utilized by radio amateurs” for weak-signal, long-distance communication and, only by circumstances — a lack of a primary occupant — has it been able to enjoy that segment as a de facto primary user.

“The Commission’s rules are quite clear that WCS licensees enjoy no entitlement to disrupt adjacent-band radio service operations,” the ARRL commented. But, the League pointed out, previous FCC actions to expand mobile broadband devices left 2300-2305 MHz vulnerable to increased out-of-band interference that would be difficult or impossible to mitigate. The ARRL said amateur stations operating in the 2300-2305 MHz band would be unable to avoid interference from AT&T Mobility’s proposed system, and that the FCC has refused to clarify the obligation of WCS mobile providers to avoid interference to Amateur Radio operations there.

The ARRL objected to what it called the FCC’s “practice of making allocation decisions which place incompatible uses in close proximity to amateur stations and then place on the amateur licensees the burden of avoiding the interference.”

“It is obvious that the result of the AT&T Petition will be a virtual preclusion of amateur access to the 2305-2310 MHz segment,” the ARRL’s comments continued. “A ubiquitous air-to-ground system which operates at and above 2305 MHz will clearly render the secondary allocation status of that segment a virtual nullity.”

The ARRL asked the FCC to recognize Amateur Radio’s “de facto primary status” at 2300-2305 MHz and to elevate that segment from secondary to primary for amateurs. It further called on the Commission to “clarify the obligation of WCS licensees in all contexts to protect the adjacent-band Amateur Service operations at 2300-2305 MHz from harmful interference.” Finally, the League requested that AT&T provide “a complete technical compatibility showing and interference analysis” that would demonstrate compatibility between its proposed service and amateur operations at 2300-2305 MHz.