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FCC Addresses 700 MHz Spectrum Issues

The FCC released a Report and Order and Order of Proposed Modification to fix the problems that have delayed use of the lower 700 MHz spectrum. Improving interoperability between different 700 MHz licensees is one of the FCC goals, as is dealing with interference from the higher powers originally allowed in the D and E blocks. The D block was used for Qualcomm's MediaFLO service before being sold to AT&T. Dish Networks recently proposed dropping its high power use of its E block spectrum in exchange for certain concessions from the FCC. Channel 51 interference has been a concern for A Block licensees in some markets. Construction requirements and deadlines were extended for some licensees.

Specifically, the FCC revised Part 27 rules to modify the technical requires for the lower 700 MHz D and E blocks to eliminate potential harmful interference while continuing to allow high value uses of the D and E blocks. The new rules state Lower 700 MHz D and E Block base stations must not exceed 1 kW ERP in non-rural areas or 2 kW ERP in rural areas and if operating at the maximum permissible ERP are limited to an antenna height of 305 m HAAT. Operations in the Lower 700 MHz D and E blocks are limited to downlink only. If higher power is needed there is now a process where a D or E block licensee can apply for higher power use, up to 50 kW ERP, if the licensee has the consent of affected 700 MHz licensees or can show no harmful interference.

In the Report and Order the FCC notes, “There also have been significant developments since 2007, when, as Dish notes, the Commission declined to adjust the 50 kW power limit applicable to the Lower D and E Blocks. Now six years later, by contrast, the demand for and use of mobile broadband services have grown significantly and continue to increase, and Lower 700 MHz licensees are deploying LTE networks to respond to this demand in spectrum adjacent to the Lower E Block, and there is no longer any high-power broadcast service being provided to consumers on this spectrum. Moreover, the record of this proceeding includes detailed studies of interference effects on the mobile devices now in use in connection with the lower power services that have displaced higher power broadcast operations in the band, which lower power services are more vulnerable to blocking interference from high power E Block transmissions.”

The FCC took no action to address claims of reverse intermodulation interference from adjacent TV Channel 51 operations to B and C Block operations. The Report and Order said, “We conclude based on the record that harmful interference from such reverse intermodulation products is unlikely and therefore is not an impediment to implementation of the voluntary industry solution for achieving interoperability.”

The Order proposes modifying AT&T's B and C Block licenses to implement the industry's voluntary solution to resolve the lack of interoperability in the Lower 700 MHz band. The construction requirements for E Block licensees were waived and the interim and final deadlines were extended. Showings using population coverage rather than geographic coverage are also permitted. The construction deadlines for A and B Block licensees were also waived with the interim deadline extended to Dec. 13, 2016. That interim deadline was removed for certain A Block licensees adjacent to Channel 51 operations. The FCC noted that nearly 190 million American consumers live outside the exclusion zones established to protect channel 51 stations from possible interference.

The Report and Order and Order of Proposed Modification (FCC 13-136) describes the challenges the FCC and Lower 700 MHz licensees faced in achieving interoperability, including two overlapping but incompatible 3GPP industry standards for this spectrum and the filings by AT&T and Dish to address these problems. Also see Dish Network Gives Up Channel 56 Mobile TV Plans for more about Dish Networks change of plans.

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.