The FCC is requesting public input on several DTV channel changes as broadcasters and the commission continue to attempt to improve reception post June 12.
In the past week the FCC has released two Notices of Proposed Rule Making (NPRM) and one Report and Order for VHF-to-UHF channel changes. As previously reported, WHDH-TV, which is operating on Channel 7 in Boston, filed to return to its pre-transition UHF Channel 42 allocation. The FCC found the WHDH-TV petition for the channel change complied with FCC rules on coverage and interference and released a Notice of Proposed Rule Making (NPRM) to substitute Channel 42 for Channel 7 in Boston [PDF].
In requesting the channel change, WHDH said it "received numerous communications from its viewers about difficulty or inability to receive its digital signal on Channel 7, apparently consistent with digital reception issues with Channel 7 in many other markets." WHDH-TV noted that the proposed Channel 42 facility would serve more people than the authorized Channel 7 DTV facility. If the NPRM is approved, the allotment for Channel 7 in Boston would be replaced with one for Channel 42 with an effective radiated power (ERP) of 948 kilowatts and a center of radiation height above average terrain (HAAT) of 288 meters.
Also this week, the FCC released a NPRM proposing substitution of DTV Channel 44 for DTV Channel 7 in Chicago [PDF] . In its petition for rulemaking, WLS-TV stated that "in the week after the DTV transition on June 12, 2009, WLS received nearly 7,000 calls from viewers" with nearly half of the telephone calls reporting reception problems.
The station also said that 47 percent of the homes visited by the FCC in late June to assist WLS had inadequate indoor reception of the station. The NPRM said WLS-TV also explained that its reception challenges on DTV Channel 7 were exacerbated "by the urban canyon effect whereby tall buildings limit coverage in urban areas" and by the fact that many of the station's off-air viewers lived in high-rise buildings where indoor reception can be "severely impaired" by attenuation from building walls.
WLS-TV said the channel substitution would increase the station's service population by some 178,771 people. If the NPRM is approved, the Channel 7 allotment in Chicago would be replaced with one for Channel 42, with an ERP of 473.3 kW and a center of radiation HAAT at 515 meters.
Gray Television has also filed a petition for rulemaking, and the FCC released a NPRM to substitute DTV Channel 49 for its KKTV DTV Channel 10 operation in Colorado Springs, Colo. Last week the FCC issued a Report and Order [PDF] approving the change after finding the channel change would comply with FCC coverage and interference rules.
Gray Television told the commission that the station has received reports of a "substantial amount of interference" on Channel 10. It also noted that a large number of viewers throughout the station's service area have experienced reception problems "inherent with high VHF digital channels in certain markets."
It added that operation on Channel 49 would raise the service prediction by "almost a million persons," and that the change would "resolve the VHF reception problems experienced by present viewers and improve the possibility for future service to viewers using hand-held and mobile devices."
The Channel 10 allotment in Colorado Springs is replaced with one on Channel 49 with an ERP of 550 kW and a center of radiation HAAT of 725 meters.
The FCC had previously released a NPRM proposing substituting Channel 5 with Channel 44 for WWAZ-TV in Fond du Lac, Wis.
On Tuesday the FCC issued a Report and Order (DA 09-1794) [PDF] approving the NPRM. The circumstances around this channel change are complex and I refer readers to the NPRM and the Report and Order for the details.
One item in the Report and Order that should be of interest to broadcasters is that the FCC agreed with WWAZ-TV that FCC rule 73.685(e) limiting the maximum to minimum radiation ratio in horizontal plane applies only to analog stations. "Section 73.625(c) applies to DTV directional proposals, which contains no constraint on maximum-to-minimum ratios for directional antennas used for DTV operations," the commission said.
Refer to the NPRM links above for information on how to file comments on the Boston and Chicago channel changes.
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.
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