The National Association of Broadcasters (NAB) has pressed the Federal Communications Commission (FCC) to safeguard existing users of the Upper C-band spectrum (3.98-4.2 GHz). They warn that further reallocation could significantly disrupt crucial broadcast infrastructure, lacking viable alternatives.

In comments submitted in response to the FCC’s recent Notice of Inquiry on Upper C-band spectrum (GN Docket No. 25-59), the NAB highlighted the substantial disruption and consolidation already faced by broadcasters following the 2020 Lower C-band auction. “The intensity of usage of Upper C-band is now at least two-and-a-half times what it was before the Lower C-band auction of 3.7 to 3.98 GHz,” the NAB stated. “Incumbent users that formerly occupied the C-band’s 500 MHz of spectrum across 41 satellites serving CONUS have been ‘repacked’ into the remaining 200 MHz, and 13 additional C-band satellites have been brought into service.”

The filing details the extensive use of the C-band: virtually every U.S. television household relies on it, and all major U.S. television networks use the Upper C-band for content distribution. It’s also vital for transportable uplink and downlink systems used for numerous broadcast events annually, including major sporting events and breaking news.

The NAB argues that alternatives such as fiber or higher-frequency satellite bands cannot match the unique capabilities and reliability of C-band satellite delivery, especially for simultaneous distribution across vast geographical areas. “C-band satellites implement hemispheric coverage, which is not typically available in Ku-band satellites but is critical to cross-continent and intercontinental delivery,” the filing stated. “While programmers often make use of [Ku-band and fiber] in concert with C-band, these alternatives alone do not meet broadcasters’ reliability standards.”

Concerns about potential interference with aircraft radio altimeters operating in the adjacent 4.2-4.4 GHz band are also raised. The NAB noted that the Lower C-band transition faced delays due to interference concerns despite a 220 MHz separation. Expanding into the Upper C-band would reduce this separation, potentially causing more interference.

The NAB urged the Commission to prioritize the protection of existing users and to take a more proactive role in resolving interference issues. The NAB suggests that any further reallocation of C-band spectrum would face significant technical and economic hurdles, stating that “all the ‘low hanging fruit’ have already been picked from the C-band,” and that viable alternatives “will be very expensive, overly complicated, or simply may not exist.”

The Commission hasn't announced a timeline for decisions regarding potential changes to Upper C-band allocations.