ALEXANDRIA, VA.: Broadcasters and their consultants know everything there is to know about transmitting a television signal. However, what happens at the viewing end of the broadcast chain might be a little murky to some.
Receive antenna manufacturers have been responding to the needs of consumers by building a new breed of receive antennas. These are designed for the shrinking TV broadcast spectrum, while providing installation options that give consumers a range of choices about how and where to install their off-the-air (OTA) TV antennas.
Still, reception issues persist and some of these are wired into the fabric of ATSC broadcasting.
"The nice thing about the old NTSC analog format was that it was durable and receivers could handle noise, multipath interference and weak signal while still delivering a (mostly) watchable picture," said Richard Schneider, president of Antennas Direct, a St. Louis-based antenna distributor. "In that environment, optimizing antenna performance wasn't that critical, and the retail selection reflected that. In contrast, ATSC receivers are much more finicky about the quality and consistency of the signal."
Schneider, whose company builds an array of indoor and outdoor receive antennas, got into the business when he couldn't find a suitable antenna for his own home theater system. He learned about design of antennas for digital reception without being bogged down with a lot of analog baggage.
"We didn't understand this at the time, but something we learned later is the importance of pulse fidelity," he said. "Some legacy antennas introduced waveform distortion that made decoding more difficult, but it turns out that newer planar antennas with a single impingement point offer very low pulse degradation and deliver a waveform to the tuner very similar to what is transmitted."
Although broadcasters have lost a lot of spectrum in the past two decades, receive antenna designers still must deal with an RF bandwidth that ranges from 54 MHz (Channel 2) to 698 MHz (Channel 51). That's nearly 13 octaves—several more than there is on a piano. Put another way, the wavelength at 54 MHz is about 5.5 meters and the wavelength at 698 MHz is about 0.4 meters.
ROUGH TERRAIN
Low-band VHF (54–88 MHz), which worked well for analog television, is proving to be rough terrain in the new digital world. That's leading both broadcasters and antenna manufacturers to abandon that part of the spectrum for more fertile fields at higher frequencies.
"We have some antennas specifically to address just Channels 7-51, and the designs are smaller and more compact," said Hank Caskey, vice president of advanced products for RCA and Terk in Hauppauge, NY. "The smaller the frequency band to cover, the easier it is to design antennas."
The Terk FD TVO wideband antenna can be mounted either horizontally or vertically. Some insiders in the video industry have praised the Terk HDTVa amplified VHF/UHF antenna for its performance.
"The log periodic style of UHF antenna is a very good one if properly tuned, and ours is," Caskey said. "This is the style of antenna the FCC used in its initial testing of UHF frequencies early in the planning processes for the digital transition (the Silver Sensor).
"On the VHF side, we use longer dipoles than most other manufacturers, which allows for better adjustments across the entire frequency band, especially low VHF," he said. "Surprisingly, many off-the-shelf antennas from Asia sold by major brands are not actually dipoles—they are monopole antennas and a reflector."
The antenna manufacturers reached for this article were in universal agreement on the number one way to improve home reception: Move the antenna outside and raise it as high as possible. Obviously, that can't always be done, so there were other tips.
"Finding a TV signal is similar to cell phone coverage—sometimes walking a few feet in one direction will make a difference between getting signal and no signal," said Cali Sartor, director of marketing for Winegard in Burlington, Iowa. "Position the antenna in a couple locations and do a channel scan each time to determine which location is the best."
Despite an economy that has hit broadcasters harder than some other industries, antenna manufacturers report that business is booming.
"With a poor economy, Americans started making choices about their finances, and a part of that is their TV viewing," said Sartor. "Our products allow people to still receive programming at a very good price point, and we've seen growth year-over-year for antennas. We have also noticed there is a consumer demand for smaller more aesthetically pleasing antennas, and reacted to that trend by launching new antennas that are well received."
THE NEXT LEVEL
Antennas Direct's Schneider took that analysis to the next level.
"Our volume is doubling about every nine months," he said. "The recession has caused many people to re-examine their monthly expenses, so pay-TV is getting more scrutiny. While the bad economy is a factor, it also helps that cable companies have continued to raise prices while lowering bitrates. Ironically, the main reason we are experiencing growth is that there has been a dramatic shift in Americans' viewing habits to broadband video, conveniently supplemented with OTA digital TV serving as the new basic cable.
WallTenna claims its ultra-thin antenna packs the same power and 30-mile range as a double bowtie rooftop model. "The two services combined [OTA and broadband] have given viewers the rationale they have been looking for to end an unhappy relationship with their cable company. Who would have predicted that Netflix would drive antenna sales?"
The WallTenna is a small, high-performance indoor flat antenna that can be hung on a wall or even stuck on a window. Snowdon Parlette, inventor of WallTenna, echoes some of these sentiments when explaining why sales are increasing.
"Free, over-the-air signals are uncompressed and in most cases, higher quality than cable," he said.
No one questions that broadcasters are experts at broadcasting, and antenna manufacturers reached for this article said that broadcasters do a good job of providing a clean, watchable signal. That's not to say there isn't room for improvement elsewhere.
"I don't believe broadcasters have done a very good job of letting consumers know how much content is available free to the end user, and how good the quality of the content available is," RCA and Terk's Caskey said. "When I tell people personally, they have no idea. I think it would benefit broadcasters to jointly educate the consuming public."
Many broadcasters have also been misleading the public by sticking to "brands" relating to channels they no longer occupy.
"[An] aid to viewers would be for broadcasters to disclose their true transmit frequencies in addition to their channel identifiers undefined," said Schneider. "Many viewers are installing the wrong antennas thinking a station's call sign/identifier is the actual transmit frequency."
WallTenna's Parlette had an intriguing suggestion for broadcasters.
"Broadcasters have discussed the possibility of setting up repeater towers to create a system much like the one currently used for cell phones," he said. "This would greatly enhance everyone's chance of capturing a strong signal."
What happens at a TV station is only half of the viewing chain. Most broadcasters are fierce about maintaining the highest possible quality signals, and thoughtful chief engineers worry about conditions at the receive end.
A dialogue between broadcasters and receive specialists might be a way to solidify the signal chain all the way to the viewer.
Bob Kovacs is a video producer and engineer. He can be reached at bob@bobkovacs.com.
