A former spokesman for the C-Band Alliance, which represented satellite companies using C-band spectrum before it was auctioned for 5G, has a bone to pick with the aviation industry.

His gripe comes after the aviation industry suggested that some interference mitigation measures taken by wireless carriers near airports be made permanent.

“The proposal by the aviation community to codify the voluntary and temporary restrictions on C-Band usage graciously indulged by AT&T and Verizon is the most outrageous proposition I have seen in 50 years of following FCC matters (and I have seen some doozies – maybe even filed one or two myself)! The FCC must just say ‘no,’ wrote Preston Padden, principal of Boulder Thinking LLC and former EVP of the C-Band Alliance, to the FCC.

Currently, the Federal Aviation Administration (FAA) has set expectations that airlines will either update equipment on their aircraft in three phases or lose access to airports during low visibility. That’s because they fear 3.7 GHz C-band signals, even with a generous guard band separating them, would interfere with old altimeters operating in the 4.2-4.4 GHz band.

The aviation industry said it’s working hard to meet deadlines to retrofit the old altimeters, but they suggested codifying some of the telecom measures; such as preventing antennas pointing 90 degrees above the horizon and maintaining the wireless spurious emissions in the 4200-4400 MHz band consistent with current mitigations, which they don’t think would compromise wireless operators’ actual use cases.

Neither Verizon nor AT&T last week responded directly to the aviation industry’s latest asks. Verizon said that it was engaging in ongoing conversations with the FAA and making good progress toward its goals, while AT&T declined to comment.

Padden told Fierce that he attended the recent Silicon Flatirons event at the University of Colorado at Boulder where resolving spectrum interference conflicts was the topic, but he was stunned that there wasn’t more discussion about receiver standards. That motivated him to pen the comments and submit them to the commission; he said he has no client or family ties to the current proceeding.

“It’s ridiculous,” he said of the aviation industry. “They had five years to swap out their altimeters. The ones they have are almost like they’re designed and intended to receive interference and it is entirely technically possible to make a receiver that rejects an adjacent channel’s interference. They should have started changing out their altimeters starting in 2017. They’d be done by now.”

Coincidentally or not, the National Telecommunications & Information Administration (NTIA) released a new report on Tuesday that describes work performed by the Department of Commerce’s Institute for Telecommunication Sciences (ITS) about 5G radar altimeter interference.

Padden said one of the conclusions in the report was a more polite way of stating what he’s trying to tell the commission: “This measurement-based observation increases the likelihood that, to the extent that any EMC problem exists between 5G transmitters and adjacent-band radalt receivers, the technical solution to such a problem might be the installation or retrofitting of more-effective RF power-rejection filters on radalt receivers for frequencies below 4200 MHz,” the ITS report states.

A look back & ahead 

The C-Band Alliance disbanded in early 2020 but at one point was comprised of Intelsat, SES, Eutelsat Communications and Telesat, with Intelsat and SES being the two biggest operators.  

Early in its history, the C-Band Alliance argued that the satellite companies should be able to negotiate private spectrum sales with wireless carriers. Padden said he still thinks they should have been allowed to sell a portion of their spectrum usage rights in private transactions and keep the money, which is similar in policy to what other licensees have done – like XO Communications, Straight Path and FiberTower.

In 2018, they were headed in that direction, but then “the politics changed on us,” he said.

Senator John Kennedy, R-Louisiana, started railing in Senate hearings about how taxpayers would get ripped off and called on then-President Trump to ensure a private sale didn’t happen.

“It was a sharp departure from prior public policy that I believe was driven by lobbyists and politics,” Padden said.

Padden has long since gone from all that and retired, but it’s worth noting his background when considering his current opposition. Prior to serving at the C-Band Alliance, he was head of government relations for NewsCorp and The Walt Disney Company.

The aviation industry has no legal right to “squat” on the spectrum in the 3.7-3.98 GHz portion of the C-band, he said. “I just think the way AT&T and Verizon are being treated is outrageous,” he said. “They paid $82 billion for this.”

If the airlines could make a credible case that they need help paying for the new altimeters, “there’s $82 billion sitting in the Treasury that can be tapped for that purpose,” he said.

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