DTV transition has been going on for the past 15 years, but digital
signals will remain a long way from perfect once the analog signals are
shut off. And several new digital signal distribution technologies are
on the horizon.
Harris-equipped transmission facility on Mount Mansfield in Vermont
serving WCAX-TV, the CBS affiliate for the Burlington market. |
One of many stations' first orders of business
will be honing digital signals with the help of antenna and transmitter
vendors such as Acrodyne, Axcera, ERI, Harris, L-3 and Rohde &
Many TV stations are moving from low-band VHF (Channels
2–6) to higher-band UHF locations. UHF offers lower interference than
VHF, but covering the same contour takes more power. Once stations are
broadcasting digital-only signals, they'll likely see coverage gaps in
their market areas.
"No one really understands all of the
consequences of offering a digital signal versus an analog one," said
Richard Fiore, senior director of transmission and mobility for Thomson
Grass Valley in Beaverton, Ore. "These questions will have to be
answered once the analog TV systems go off the air."
stations have dipped a toe into the shutoff with temporary tests. Rolin
Lintag, a veteran transmitter engineer said those stations, "have seen
what they are up against as far as actual coverage and viewership are
concerned. But most TV stations have not done this yet, and are
clueless as to what exactly will happen to their viewership come Feb.
FILLING THE HOLES
transmission is one possible gap filler. The Federal Communications
Commission OK'd DTx in November after kicking it around for years. DTx
is something broadcasters are just starting to ponder. First, they just
want to make sure the transition goes off without a hitch.
|Richard Fiore, senior director of transmission and mobility for Thomson Grass Valley |
think everyone is going to start talking about DTx, but they are going
to want to optimize their main signal first," said Rich Redmond,
director of strategic marketing at Harris Corp. Broadcasters have until
August 2009 to apply for special temporary authority to set up DTx
transmitters across their service areas. After that, they will have to
In Wilmington, N.C., the one market where the
FCC actually saw what happened when the analog TV signal was shut off,
Raycom-owned NBC affiliate WECT-TV lost part of its de facto coverage
area when it moved its transmitter closer to the ocean to better serve
viewers in its actual designated market area.
WECT does not plan
to deploy DTx to retain its out-of-market viewers, said Dan Ullmer,
chief engineer of Raycom's WECT and WSFX-TV in Wilmington.
ended up here in the late '90s with a signal pattern where much of our
signal went out of our market," Ullmer said. "When we were constructing
our new facilities, it didn't make sense to send so much power outside
of our market. We had to move our tower sites so our digital broadcasts
would better cover our actual market. Now, many viewers in our DMA have
a much better signal."
Still, if WECT wanted to serve its now
disenfranchised but out-of-market viewers, distributed transmission
would be the way to go, according to S. Merrill Weiss, president of
Merrill Weiss Group LLC and the originator of DTx.
It was WECT's
experience that helped the FCC realize that DTx would come in handy in
the new digital world, Weiss said. If TV stations shut off their analog
signals and millions of over-the-air TV watchers lose their signals as
a result—and some 15 percent of U.S. households still receive their TV
over the air—the FCC will shoulder much of the blame.
broadcasters start looking closely at the actual coverage of their
digital signals, DTx will be an actual solution to those types of
problems," said Jack Wilson, director of marketing and business
development at Lawrence, Pa.,-based Axcera, one of the few companies to
offer equipment that's been deployed in real DTx systems.
bit further down the road, broadcasters are looking seriously at mobile
broadcasting. ATSC committees are working furiously to roll out a
working standard come first quarter 2009. Manufacturers are hot to
demonstrate working devices at the National Association of
Broadcasters' conference in April, and have them to retailers by next
|Rich Redmond, director of strategic marketing at Harris Corp. |
Building out a mobile broadcasting system is much
like building out a DTx system; i.e., more low-power transmitters would
have to be distributed across the coverage area to provide a consistent
signal wherever a viewer may wander.
"For terrestrial broadcast,
the receiving equipment is normally an outside, directional, high-gain
antenna," Axcera's Wilson said. "With mobile services, you are
broadcasting to a small mobile device that's in someone's hand or their
car. It has a low-gain antenna, it's not directional, it's often moving
and it's often in a building. To do mobile services well and to get
in-building coverage, you need multiple low-power transmitter sites."
Many in the broadcast industry look at mobile TV as the first real business opportunity offered by the digital spectrum.
TV gets TV back to the best use of the spectrum, now that we have cable
and satellite signals delivered direct to the home," said one broadcast
engineer. "There's just not as much value in using the over-the-air
signal to transmit to these fixed devices. It makes more sense… to
transmit the signal to portable devices or devices not connected to
cable or another connection, such as laptops, cell phones, in-car GPS
systems, cell phones or portable media players."
"We think that
mobile is something that can reinvigorate the value of the spectrum for
broadcasters," said Dave Benco, transmission program manager for Rohde
& Schwarz of Munich, Germany. "Their competitors are alternate
delivery methods such as cable, satellite and the Internet. Mobile
isn't such a benefit if you are talking about reaching a 54-inch screen
in someone's living room because that's not moving around, but mobile
brings a real benefit when you realize how many people are walking
around with wireless devices."
Still, vendors aren't counting their digital chickens before they hatch.
still have not heard what the business model will be for ATSC MPH
systems," Thomson Grass Valley's Fiore said. "How much will people be
willing to pay each month for this additional service? Will advertisers
buy time on it? Do people really want to watch television on their cell
THE POCKETBOOK PINCH
|Jack Wilson, director of marketing and business development forAxcera |
the worsening economic scenario means all bets are off in terms of
implementing any new technologies. Broadcasters already have spent
billions on converting to digital and now high-definition. Building out
their digital networks and adding mobile offerings is just an
additional expense in a difficult marketplace.
DTx systems can
run anywhere from $50,000 for one lower-power transmitter to $500,000
for 10 such transmitters or one high-power transmitter. And then
there's the cost of getting the signal to those isolated sites, which
requires installing a microwave link, running a fiber connection or
adding a satellite uplink.
"The technology is there through DTx
for a station to fill in holes in its coverage to replicate the analog
coverage with the digital signal even if they are transmitting on UHF.
But the question is: if most people are watching television on cable or
satellite, is it worth the money to do it?" asks one engineer.
economy is just an unknown," said Benco, who still expects many
broadcasters to go forward with both DTS and mobile systems as soon as
it becomes feasible both economically and technically.
broadcasters already have made a decision that mobile services will be
an important part of their future. I can't imagine there was ever a
time when the capital cost of a project wasn't very important, so of
course broadcasters would want to do these deployments in a way that's
purposeful and makes economic sense."