Thousands are complaining loudly that they can no longer find stations that switched from UHF to VHF channels last Friday as part the final transition to DTV. Nobody knows why for sure, but the speculation blames everything from UHF-only rabbit ears to improperly retrofitted transmitters to inadequate broadcast power.
“What about all of us that spent hundreds of dollars buying and installing the antenna during the testing period and now we see that it was wasted money because 6ABC switched to VHF,” wrote Nanopardo on the Web site of ABC-owed WPVI Philadelphia. “Did you say that we were all set if we got reception during the testing period? Now we are not??? PATHETIC!! And CRIMINAL!!”
WPVI was not alone in drawing such ire. Other TV stations that had moved their digital channels from the UHF to VHF bands as part of last Friday’s final switch to DTV were being swamped with such messages from unhappy viewers via the Web or by phone.
The VHF problem quickly became the DTV transition story this week, causing not only affected stations to scramble, but also the FCC.
While stations appealed to the FCC for more power or new channel assignments, the FCC and broadcast engineers tried to figure out why the VHF channels were not doing the job and come up with solutions.
The VHF problem is contributing to the FCC’s difficulties in getting the last of the over-the-air-only homes equipped for digital with a new TV sets or a converter box.
Nielsen said yesterday that as many as 2.3 million homes are now without service, although others believe that number is vastly inflated.
With its popular programming, ABC was at the center of the storm. Eight of its 10 station made the troublesome UHF to VHF shift, and six of them are in Top 10 markets, including New York, Los Angeles, Chicago, Philadelphia, San Francisco and Houston.
Like WPVI, ABC’s Chicago station, WLS, was a hot spot, drawing thousands of complaints from viewers who were receiving the station on its temporary DTV channel 52, but lost it when it switched to its permanent DTV assignment, channel 7, last Friday. (WPVI had moved from channel 64 to channel 6.)
Another problem market was the FCC hometown of Washington. There, two stations, were trying to cope with incessant complaints after making U to V switches: Allbritton’s WJLA, which went from channel 39 to channel 7, and Gannett’s WUSA, which went from channel 34 to channel 9.
All told, 483 of the nearly 1,800 full-power TV stations now dwell in the VHF band. Of those, 40 are assigned to the low VHF band (channels 2 through 6) and 443 to the high VHF band (channels 7 to 13).
Prior to the analog cut offs on Feb. 17 and June 20, only 215 were operating in the VHF band with their “pre-transition” digital assignments.
Broadcast engineers cite several reasons for why viewers might be having trouble with the digital VHF stations.
Because most DTV stations are now UHF, they say, many consumers may have purchased UHF-only antennas or antennas with poor VHF elements. Some of the most popular antennas on the market perform poorly at VHF, they say.
Other stations whose permanent digital channel is the same as their old analog channels are now using their old analog transmission plant for digital and that plant may not have been adequately retrofitted for digital, they say.
Finally, they say, some of the new VHF stations are simply underpowered.
VHF stations, particularly in the low VHF band, are susceptible to made-man interference emanating from everything from taxi cab radios to power lines to vacuum cleaners. The so-called impulse interference can only be overcome with more power that lifts the broadcast signal out of the noise.
Recognizing the impulse-noise problem, some broadcasters had applications at the FCC to maximize power long before the June 12 analog deadline. Others are rushing to the agency with requests this week.
Of course, power increases will be limited by the co-channel and adjacent channel interference they would cause. WLS may need more power, but it shares channel 7 with KJCT Grand Rapids, Mich. “Those two eventually start to collide with one another,” said one source.
What perplexes the engineers is that VHF reception seems to be more of a problem in some places than it does in others. For ABC, for instance, it seems to be more of a problem in Chicago and Philadelphia than it does in New York and Los Angeles.
“There are multiple variables here,” said a broadcast engineer. “There are more variables than we have equations to solve them right now. You have to look at the situation analytically and avoid panicking and assuming VHF is simply bad.”
The problem with taking that analytic approach is that thousands of viewers are complaining about the loss of service and demanding answers fast.
Stations caught in the maelstrom were hunkering down.
ABC engineers declined to be interview, deferring calls to the PR department which limited its comment to a terse statement: “The FCC is well aware of the issues surrounding DTV and VHF reception and is working on potential solutions. Viewers also need to know that they need to buy a good quality VHF antenna to make sure that they are able to receive all VHF stations.”
Perhaps embarrassed by the unexpected fallout, FCC spokespersons and engineers also did not return multiple phone calls seeking comment on the situation.
Some broadcast engineer say the VHF problem was years in the making.
“Engineers in the business were saying 10 years ago that the way the FCC is going about it has nothing to do with the real world,” says Oded Bendov, president of TV Transmission Antenna Group and winner of the NAB TV engineer achievement award winner of 2005.
In making its channel and power allocations, the FCC used “an ideal [digital] receiver that doesn’t exist connected to an antenna that doesn’t exist and software to way over-predict service that was never validated in the field.
Bendov says the FCC also did not adequately test DTV with indoor antennas.
“There’s a special problem for VHF stations. If you connect [indoor antennas] to a DTV converter box, they actually degrade the performance of the receiver quite considerably. The receiver suffers a punch in the stomach when it’s connected to these antennas.
“All TV stations, UHF and VHF, are not getting the service the FCC said they would, but when it comes to indoor reception there’s a special problem for VHF stations,” Bendov says.
Erik Swanson, a consulting engineer at Hatfield and Dawson, agrees.
“One of the DTV report and orders in 1997 acknowledged that operations, particularly in the low VHF channels are ‘subject to a number of technical penalties,’ he says. “The FCC knew in ‘97 that these channels were problematic.”
But Bendov also offers some hope to stations now saddled with VHF channels, saying that the FCC made its digital channel assignments with extremely conservative interference assumptions. He estimated that low VHF channels should have been given 16 times more power and high VHF 6.3 times more to adequately serve indoor antennas.
Because ABC is not talking, it’s not clear why it ended up with VHF channels at most of its stations. “Why ‘PVI chose to go to channel 6 is beyond my wildest imagination. It makes no sense whatsoever,” says Bendov, who says that he designed WPVI’s antenna.
Some speculate that it was primarily a marketing decision. The stations wanted the same digital channels as analog channels, even though the DTV standard’s PSIP feature can mask the real digital channel numbers and allow station to continue branding with their old analog numbers.
While the broadcast engineers at ABC and elsewhere continue to work the problem, their viewers will continue to grumble.
“It’s the height of arrogance that we buy a new antenna when we are receiving all the digital channels EXCEPT yours,” said kavana914, another of dozens of complaints piling up on the WPVI Web site.