Many stations that selected their analog channels as their final DTV channel found that they couldn't return to that channel without causing interference to an already authorized DTV station. Stations that received a conflict analysis letter concerning their channel election were required to submit First Round Conflict Resolution Form 383 by Aug. 8, 2005. On July 28, the Association of Federal Communications Consulting Engineers requested the deadline be extended thirty days. The FCC did not agree to the thirty-day extension found but there was good cause to grant a seven-day extension to Aug. 15, 2005, "to provide licensees additional time to analyze their channel elections and coordinate their responses."
Stations with at least one in-core (2-51) channel filed First Round Election Forms by Feb. 10, 2005 selecting one of their assigned channels for DTV operation at the end of the DTV transition. If the elected channel was the station's NTSC channel, the FCC then analyzed it to determine the extent of interference, if any, to an in-core existing DTV channel elected in the first round; to an in-core DTV channel of a station that elected its NTSC channel if it might have to revert to its DTV channel; or to an NTSC channel elected by another station in the first round. Stations with channel elections that were expected to increase interference by more than 0.1 percent were sent letters dated June 7, 2005 and given 60 days (now 67 days) to resolve their conflicts by mutual agreement, modification of facilities, electing their DTV channel (if in-core), or giving up both assigned channels and participating in the second round of channel elections.
The procedures for filing Form 383 and Schedule A, are in the FCC Public Notice released Aug. 2, DTV Channel Election: First Round Conflict Decision Extension and Guidelines for Interference Conflict Analysis. The procedures vary depending on how a station decides to resolve its conflict. Stations with conflicts that fail to file Form 383 will be deemed to have elected their in-core DTV channel, or, if their DTV channel is out of core, they will be deemed to have given up their in-core NTSC channel (and DTV if the station has only one channel) and "may be expected to participate in the second round of channel elections."
As I explained last year in my RF Technology Column - Choosing a Final DTV Channel, a channel that was suitable for NTSC operation may cause interference problems when switched to DTV, as both co-channel and adjacent channel interference ratios are much stricter for DTV to DTV interference than NTSC to DTV interference. With the tight 0.1 percent threshold for increased interference, this made it difficult for many stations in congested areas to use their NTSC channel for DTV. The FCC recognized this problem in the Second DTV Periodic Review and, as the Public Notice states, "would allow licensees with out-of-core DTV channels to exceed this interference level to afford these licensees an improved opportunity to select their in-core NTSC channels." The Second DTV Periodic Review did not, however, specify how much it would allow this level to be exceeded. The Public Notice clarifies this, stating, "In general, the staff intends to approve such in-core elections if they do not cause more than 2.0 percent additional interference to other stations (based on their DTV replication facilities, not their maximized facilities). Such licensees must notify us in writing that they are eligible for and wish to take advantage of this special treatment, as described in (4), above."
See the Public Notice for details on the filing requirements. If one station electing its NTSC channel decides to go back to its DTV channel or is able to resolve conflicts affecting its use of its NTSC channel for DTV, this could change the interference situation for other stations. The Public Notice describes how to handle these situations.
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