The FCC’s proposal to expand the use of Distributed Transmission Systems by television stations operating with the new ATSC 3.0 transmission system was published in the Federal Register today (here). That publication announces that the comment deadlines on the FCC’s DTS Notice of Proposed Rulemaking are due by Friday, June 12, 2020, and reply comments will be due by Monday, July 13, 2020. While we mentioned this proposal in passing when discussing a proposal to allow FM stations to use boosters to provide an FM version of a distributed transmission system, we have not written in detail about this proposal. With the comment deadline now set, let’s look at some of the questions asked in the rulemaking proposal.
First, it is worth explaining the concept of a distributed transmission system (sometimes referred to as a “single frequency network” as it uses multiple stations on the same frequency to reach its audience). Traditionally, television stations have operated with a single high-power transmitter from a location central to their coverage area. Thus, viewers close to the transmitter get the strongest signal, and that signal dissipates the further that a viewer gets from that central transmitter site. Station signals are protected from interference to a certain contour where it is assumed that the majority of viewers will be able to receive over-the-air an acceptable signal most of the time. But even at the edge of these protected contours, the FCC’s projections assume that many viewers will not be able to receive an acceptable signal at all times. Distributed transmission systems are already in use by television stations in certain markets to fill in holes in station coverage – and have been particularly useful in markets with irregular terrain where mountains or other obstructions preclude one centrally located transmitter from reaching audiences far from the transmitter site. Locating a second transmitter on the same frequency behind the terrain obstruction allows better reception for viewers who might otherwise not receive an acceptable over-the-air signal. However, currently, the DTS transmitters cannot extend the noise-limited protected contour of a station “more than a minimal amount” beyond that which the TV station would be predicted to have from a single centrally-located transmitter site. The NPRM in this proceeding, based on a petition filed by the NAB and America’s Public Television Stations (see our article here on the Petition for Rulemaking filed by these groups), looks to allow for wider use of DTS.
The proposal is to expand the area in which DTS transmitters could expand the service of a TV station. While the proposal would still require that the transmitter site of any DTS transmitter be located within the noise limited contour of the station from a centrally-located transmitter site, the requirement that the extension of the contour be no more than a minimal amount would change. Proponents of the expansion argue that DTS systems should be allowed to be used to better serve the residents of a station’s service area by providing more uniform strong signals throughout a station’s service area. Those on the fringes of a coverage area should not get weaker signals that those in the middle of the market. By providing stronger signals throughout the market, ATSC 3.0 proponents argue that the new services that can be provided by the new transmission system can better be enjoyed by all residents of the service area.
The FCC proposes that, for UHF stations, the expansion of the station’s service be allowed to what would be the 36 dBu contour of the centrally-located station (different limiting contours would be used for VHF stations). The Commission asks for comments on that choice of contour. It also asks for details about the benefits that such an expansion would provide, and costs that would be incurred.
But the NPRM also asks questions raised by parties who are unsure of the merits of any proposal for expansion of service by these TV stations. Would the greater spillover of the signal beyond the noise-limited contour (and the minimal amount of spillover now allowed) create the potential for interference with LPTV and TV translator stations? If so, how should that interference be treated? Is the spillover part of the primary signal of the TV station that would be allowed to interfere with the LPTV or translator operation, or would it need to protect these otherwise secondary signals?
Similarly, proponents of white spaces devices ask about the impact that expanded contours would have on service from their operations. The FCC even asks whether, by allowing stations to expand their coverage area, they are being granted rights to service that should be open to competing applications – asking how the “Ashbacker Doctrine” (which states that the FCC cannot award new licenses without providing an opportunity for competing applications) applies to these proposals. Here, as the 36 dBu contour of UHF stations is the contour at which a station would interfere with another station, some would argue that Ashbacker is not triggered as no service could be provided in these areas anyway.
Questions of timing, scope and implementation are also asked. Should these changes be implemented now, or should they wait until ATSC 3.0 is up and running and the FCC and operators have more experience with the service? Should LPTV, Class A and TV translators be able to provide similar DTS operations? Should the expansion even be allowed for stations that continue to operate in ATSC 1.0? Are there special considerations for signals of stations that may be hosting multiple licensees through some sort of channel sharing? Can single sites accommodate multiple licensees looking to provide DTS operations?
These and many other questions are teed up by the FCC in the NPRM. Interested parties now have a date by which they can weigh in on the many issues advanced by the FCC. Note the June 12 comment deadline and, if you have an opinion, now is the time to advance it as the Commission weighs this proposal.