FCC Proposes Sharing 2 GHz Broadcast Auxiliary Frequencies with Department of Defense
In a Notice of Proposed Rule Making released July 7, the FCC proposed allowing the U.S. Department of Defense (DOD) to use 2025 to 2110 MHz for earth stations at 11 sites that support military space operations. Usage would be on a co-equal, primary basis to non-Federal government operations. The FCC said allowing DOD to use these frequencies would help clear the 1710-1755 MHz band that is being transferred from the federal government for use by non-federal government advanced wireless systems.
The NPRM explains that the 2025-2110 MHz band is currently allocated to fixed, mobile, space operation, Earth exploration satellite and space research services throughout the world. Since the space operations are limited to uplink and space to space applications, it notes that these operations have successfully shared the band with broadcast auxiliary service (BAS) electronic news gathering (ENG) systems for many years. There are a total of 1,680 licensed BAS links in this band, according to a table in the NPRM.
In comments in the proceeding, Joint Broadcasters did not oppose NTIA's proposal to allow 11 DOD transmit earth stations to use the band, but raised several concerns, primarily that the DOD operations not disrupt or constrain BAS operations. Because the NTIA did not disclose the technical parameters of the DOD operation in the band, the Joint Broadcasters' comments said neither the FCC nor the TV industry can make a meaningful assessment of the impact of the NTIA proposal.
The FCC NPRM offered this statement in support of the proposal:
"Further, we observe that DOD TT&C earth stations use extremely large antennas and high transmitter output powers to produce highly focused and very powerful main beams and could have large coordination areas. Thus, these transmit earth stations could potentially cause interference to BAS operations. Accordingly, we find that coordination will be necessary between DOD earth stations operating in the band 2025-2110 MHz and 2 GHz BAS operations. In this regard, we will maintain our longstanding policy that first-licensed facilities have the right of protection from later-licensed facilities operating in the same frequency band. However in this regard, we observe that currently Federal Government earth stations at 29 sites are authorized to transmit in the band 2025-2110 MHz in the United States. We believe that--with coordination DOD earth stations at an additional 11 sites may also successfully share frequencies in this band with the incumbent BAS operations. We base this belief on a variety of factors that can facilitate sharing of this spectrum. These include terrain shielding and the facts that some of the antennas may be pointed out to sea, that each TT&C channel is generally used only for relatively short periods of time, that a TT&C channel is expected to impact only one BAS channel, that earth stations controlling GSO satellites may point at such high elevation angles as to have a minimal impact on BAS operations, etc. We solicit comment on the specific factors that would permit proposed spectrum sharing."
However, the FCC NPRM also expressed concern about the impact on future BAS growth in areas near the 11 DOD telemetry, tracking and control (TT&C) uplink earth stations, "especially in light of the ongoing digital television transition." While the FCC feels sharing is possible, there was also concern about interference to adjacent bands (1990-2025 MHz and 2110-2155 MHz) from out-of-band emissions and receiver overload. The adjacent bands have been reallocated from BAS use to fixed and mobile services. The NPRM solicited comment on whether other bands may be more appropriate for the 11 TT&C stations.
This NPRM also impacts amateur radio operations in the 2390-2400 MHz band. For more information, download the Fourth Notice of Proposed Rule Making--ET Docket 00-258