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An
exploration of terrestrial broadcast, by
Ken
Freed Part
1 of 2 Once
a television production is "in the can" (to borrow
a film term), the fun really begins. The selection
of appropriate distribution channels for video
programming depends on the content and format. A
great programme can fail just as miserably as a
lousy programme if distributed through the wrong
channels. Understanding the technologies used for
television content distribution can help determine
the best venue for any given educational programme
or series. TERRESTRIAL
BROADCASTING OF ETV PROGRAMMES Analog
Television Terrestrial
antenna broadcasters deliver programming at no cost
to everyone within range of their antenna. For
maximum reach, an antenna tower needs to be perched
atop the highest point in the region, a mountain, a
big hill, an office skyscraper. The range of the
signal also is determined by the power of the
station, how many watts or megawatts of power the
transmitter can generate. The signal radiates out
from the antenna in all directions. Broadcast
signal airwaves tend be fairly long, so distances
from crest to trough are measured in meters to
kilometers. Very high frequency (VHF) waves vibrate
at a slower rate than ultra high frequency (UHF).
The first broadcast
stations to launch operations 50 years ago used VHF
signal channels. These were designated in the
marketplace with low numbers, BBC1-2 and Channel 4
in the UK, for instance, or channels 1 through 9 in
the USA. The UK does not yet have UHF stations, but
UHF channels in the USA and typically have higher
call numbers like Channel 20, Channel 31, Channel
59. Every nation and region has its own unique
broadcast infrastructure. The mechanics of broadcast
TV transmission are universal, however. Using a
router and switcher system, a master control center
mixes together the individual programmes with the
assorted interstitial materials (commercials,
public service announcements, broadcaster
identification spots, programme promotions), and
then sends the full signal to the transmitter
located at the antenna tower. Methods of moving the
signal from the TV station to the transmitter
include bundled telephone lines, coaxial cable,
optical fiber, microwave, and satellite. A
transmitter contains a large tube, up to three feet
across and two feet high, that pulses out the
signal at the assigned frequency. The design and
manufacturing of both VHF and UHF television
transmitters embodies a major international
business, as does producing the other equipment
used in television operations. (See Chapter 8 for
key players.) Home viewers pull the long
waves from the air with a rooftop or set-top
antenna, which is attached by wires to the back of
the TV set. This equipment is produced by consumer
electronic companies. Global ventures like Philips,
Sony, Panasonic, General Electric (Thomson), and
others produce both consumer electronics and
professional equipment, allowing them to play on
both sides of the street. Educational TV producers
have to deliver their programming to broadcasters
in a form that accounts for the technical
requirements of both the broadcasters and the
receivers. While this is common sense, too many ETV
ventures have fallen flat from lack of compliance
with technical standards. A TV station with low-end
or poorly maintained equipment might degrade the
quality of a programme's picture and sound when the
programme is broadcast, but the most advanced
station cannot improve the quality of an inferior
production. Distributing educational
TV programmes by terrestrial antenna broadcasting
has the advantage of making the learning content
available at no charge to everyone within range of
the TV station . Educational broadcasters in the
USA like to say that free TV is the most democratic
way to educate the public for responsible
citizenship. This concept still applies in the UK
although television owners must pay an annual
license fee to BBC in order to receive the "free"
programming. From a business viewpoint, the
question is, who pays for these free broadcasts?
Commercial advertising has become the answer for
most broadcasters, but most educational TV is on
public broadcast stations, which in some nations
are wholly subsidized by the government and in
others. In the USA, viewer membership dues fund up
to 90 percent of PBS station costs and programming
acquisition. Digital
Television Now
a new challenge faces broadcasters and those
producing ETV content for the broadcasters &emdash;
called digital terrestrial television (DTT) in
Europe and simply digital television (DTV) in the
Untied States. From end to end, full
deployment of digital television requires the
replacement of almost every piece of equipment
within a broadcast operation's facility and within
a viewer's home. For equipment manufacturers,
digital TV represents an explosive business
opportunity coupled with an incentive for technical
innovation to pass the competition. For ETV content
producers, digital TV represents an opportunity to
imagine and create richer and more effective
educational programmes using the wide-screen format
of motion pictures. And what do consumer get out of
DTT? Not only do they get cleaner, brighter,
sharper pictures and sounds than ever was possible
with analog TV, they also gain access to a host of
interactive services (the Internet only hints at
the possibilities). Interactive broadcast ETV, of
course, depends on broadcasters being willing to
make use of set-top receiver boxes or else the next
generation of TV sets with built on modems for an
upstream channel. The deployment of digital
TV services will take place over the next
generation, with the major cities being the first
to receive digital service before the year 2000.
During the transition period while analog TV sets
are being replaced by digital TV sets, broadcasters
will have to simultaneously transmit both analog
and digital signals at different frequencies. The
duration for this expensive period of dual
operations will be influenced by the rate of
consumer acceptance, yet also by the rate of TV
operation's conversion, as determined by fiscal and
human resources. In the United States, for
example, there are about 1100 television stations.
Each will need to upgrade their transmitter
antennas for digital operations. An HDTV tower must
be higher than an analog NTSC antenna, which may
mean building a whole new tower complex. In the
entire nation, however, there currently are only
about eight crews with the technical knowledge and
skills needed to do the job right, the best crews
averaging about one month per tower. Working at top
speed, these crews will be lucky to upgrade 1100
stations within 10 years, appreciably longer than
the optimistic timetable fixed by the Federal
Communications Commission. In the UK with only 207
television broadcast stations, the task of
upgrading all the antenna towers is not as
daunting, but add in the 3200 signal repeaters that
ensure coverage throughout England, Scotland,
Wales, Northern Ireland, and other British
holdings. since each repeater must be upgraded, the
enormity of the national undertaking becomes
apparent. And stations wanting to launch DTT
services cannot just up and do it. They must go
through a rigorous licenses process from either the
BBC or the ITC (Independent Television Commission),
both charged with standards compliance. Governments generally are
in command of the rollout of digital TV services.
The allocation of electromagnetic spectrum is
controlled by national governments on the
philosophical premise that the spectrum is a
natural resource that belong to the people as a
natural right. Broadcasters are granted licenses to
use assigned frequencies in the spectrum are viewed
by their governments as being given a sacred trust.
giving broadcasters. Political realities affect
technological visions. If seeking niche
television business opportunities, whether in
educational or commercial broadcasting, notice how
a demand for qualified digital upgrade crews will
grow and hold steady for at least a decade. The
people paid to do the upgrades will make good
money, but what of those paying them to do the
work? Since upgrading a
broadcast station from analog to digital can
surpass £2 million or $3 million without much
effort, how is this expense justified for TV
operations earning appreciably less in annual
revenues? The investment is worthwhile only if the
upgrade can produce new revenue streams through
interactive digital services. For producers of
digital wide-screen programmes, their facility
upgrade expenses start at about £500,000,
which is not small change, but much easier to
recover though national and international sales of
even one quality educational product. CABLE
DISTRIBUTION OF ETV PROGRAMMES Cable
operations in the UK and Ireland are regulated by
the Programmes and Cable Division of ITC, which
Licenses cable and satellite programme services
along with monitoring their compliance with the
Programme Code. The division also works to support
high quality and diversity in national and regional
services. Cable is a relatively new
phenomenon in the United Kingdom, and penetration
hovers slightly above 20 percent. In contrast,
cable penetration in the United States recently
passed 65 percent of the 100 million households
being served by about 9,000 cable systems, most of
them being owned by a multiple system operator
(MSO) like Comcast, Time-Warner, Charter, and
others. Since so little of the UK has been wired
for cable, construction crews can start fresh and
lay a hybrid line of fiber and coaxial cable for TV
and phone services. For instance, as of September
30, 1997, new systems built by Comcast UK passed
more than 1,147,000 homes (72% of the homes in
their franchise areas), serving 285,000 cable
subscribers, 335,000 residential telephony
subscribers and 10,500 business telephony
subscribers. Cable penetration in the UK is
expected to increase year by year, yet the lower
numbers give UK cable operators an economic
advantage in that their new systems can be designed
and built for digital from day one. American cable operations
are not so fortunate. They must rebuild existing
plant. After the lengthy process, years earlier, of
obtaining rights-of-way to dig up the streets and
fields, to cut trenches around or through home
garden, cable crews now must go back and dig up all
of these old lines and replace them with hybrid
fiber coax (HFC) lines. In some systems, the HFC
lines are being bundled with twisted pairs of
copper telephone wires, the architecture created by
USWest for their of broadband cable TV trial in
Omaha, Nebraska. Revenues from cable
subscriptions and advertising are helping to fund
the costly upgrade to digital, but the cable
operators are counting on new revenue streams from
digital services to recover their costs and turn a
profit. Interactive education is one of the
services seen as central in the cable industry's
growth strategy . Producers of educational content,
therefore, are smart to understand the concerns of
cable operators and make sure they deliver content
in whatever video recording format a cable system
prefers (another opportunity for standards
conversion). On the technology side,
beyond the upgrade to wide-screen HDTV pictures,
improvements in the cable infrastructure can
support such interactive services as
video-on-demand and home shopping, often deemed the
twin cash cows pulling the digital wagon.
Delivering these services requires a high-capacity
digital server with a large memory buffer and
high-speed ports for incoming and outgoing traffic.
Because video is so bandwidth hungry, already using
6 megahertz for a single analog channel, the
digital video file servers at the heart of
multichannel on-demand and transaction services
must be able handle as much volume in an hour as
Internet file servers handle in a day or a
week. Digital
Compression The
magical word to solve the bandwidth problems is
compression. When TCI chairman John Malone was
misquoted in the early Nineties and all the hype
began about "500 channels," he was talking about
digital video compression. Crunching the size of
the digital datastream allows more content to be
packed into less space. At a 10:1 compression
ratio, a 50 channel cable system can have 500
channels. Video compression is
achieved, in part, by dropping redundant
information from the data stream describing each
frame of video (at 30 frames per second). In a wide
shot of a lone figure in the distance walking down
a country road, why keep sending over and over
again the data packets controlling the pixels that
make up the unchanging mountains and trees and sky?
Instead, only refresh the data packets for those
pixels that do change from frame to frame, these
few pixels near the center of the screen depicting
the walking figure. Video with more movement cannot
be compressed as much as video with little motion
because more pixels change from frame to frame in
action scenes. This is a simplification,
admittedly, because identifying data for every
pixel in every frame needs to be sent for each
frame just to keep the pixel grid in order. But now
you visualize the essence of digital compression.
You also can benefit from knowing that various
algorithms are used to predict motion from frame to
frame, so still more bits of data can be compressed
out of the transmission. Also, know that some
compression methods delete data in the process,
degrading the picture quality. The trick is finding
the right balance between compression ratio and
image resolution. The world standard for
video compression is MPEG-2, developed by the
Motion Picture Experts Group. Compression under
their previous MPEG-1 yielded too much data loss,
so they developed a second, more sophisticated
compression method. MPEG-2 actually is a set of
compression tools that sample the different levels
and profiles of video's luminance and chrominance,
brightness and colour. MPEG-2 encoders and decoders
are produced by almost every major TV equipment
manufacturer, including such European giants as
Philips and Thomson. Within the TV industry,
there's a popular paraphrase of George Orwell that
goes, "All MPEG is created equal, but some MPEG is
more equal than others." MPEG-2 at Main Level, Main
Profile is most commonly used for transmitting
video over cable, satellite and microwave systems,
whether the receiver is another television center
of a viewer's TV at home. Unfortunately, MPEG-2 at
MP/ML must be decompressed before it can be edited,
and signal degradation always occurs upon
recompression. So, Professional or Studio Profile
MPEG-2 has emerged for in-house signal processing.
Studio MPEG's higher sampling rate and structure
allow editing on-the-fly, such as inserting a
station ID into the lead-in for a programme, or
perhaps dubbing in another language or inserting
translated text at the bottom. Educational television
content producers, like other video producers, are
learning to plan for compression during production.
Awareness of the compression method expected to be
used may influence shot composition and scene
lighting. Also, more and more cable systems are
asking producers to deliver their programming
content already compressed, perhaps bounced of a
satellite to the cable headend. Cable
Advantages In
addition to the digital compression, the cable
industry is investing tremendous resources in the
deployment of the cable modem, which will support
high speed data services. The standard
configuration will be one cable line coming into
the home or office or classroom which then enters a
splitter with one line going to the TV and another
line going to a cable modem attached to the
computer. As the TV and PC converge, the cable
modem may become obsolete, but that's more than
decade away. Meanwhile, cable services are counting
on the fees for cable modem rentals and data access
services to help pay for their rollout of
video-on-demand and interactive transaction
services like home shopping and remote banking. The
moneys from these services will subsidize cable's
growing educational activities. The primary technical
advantage of cable services over broadcast,
satellite or microwave services is the cable
itself. Only a cable inherently supports
symmetrical two-way communication, as much content
going upstream as coming downstream. This is not an
issue now, when the only upstream traffic is short
bursts of data commands on what to send downstream.
But as video telephony services begin (making
today's teleconferencing look crude in comparison),
cable companies may be in the best position to
compete head to head with the telephone companies
for telecommunications customers. In response, many
of the telephone companies (such as USWest and Bell
Atlantic in the USA, British Telecom in the UK,
France Telecom and Deutche Telecom on the
continent) have prepared to offer digital video
services over their own copper or fiber telephone
lines. One day, the now stark divisions between
different types communication companies may blur
into nothingness when all network operators offer
video, data and voice services. Until then,
recognizing the distinctions is important to any
savvy investor. Education is one area
where the distinctions become apparent.. The cable
industry, at least in the United States, is
investing hundreds of millions of dollars into
educational cable services targeting both the TV
and PC platforms. In part, the industry is
attempting to win friends and influence people in
communities where they have lost favor due to
arrogant customer service attitudes (a product of
monopoly franchises with local governments). But
this thinking is subsumed by the leading voices
within the cable industry who share a genuine
commitment to education, such as William Samuels at
ACTV, such as Bernie Luskin while at Jones (he's
now at Fielding Graduate Institute), such as Carol
Vernon at Cable in the Classroom, and the list is
growing. Along with public broadcasters,
cablecasters are the educators' best friend in the
television business. (c)
1998-2005
by
Ken
Freed.
Based on the book, Financial
Opportunities in Educational
Television, by Judah Ken Freed. . New
in the CASTING
THE NET OVER GLOBAL
LEARNING An
comprehensive overview of critical advances in k-12
and higher education along with corporate training
and lifelong learning.
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