DIGITAL GOES THE AERIAL ROUTE

It’s all systems go: ordinary, ground based aerial television in SA is going digital. The national treasury has agreed, in principle, to provide state owned broadcast signal distributor Sentech with the money to upgrade SA to digital terrestrial television (DTT).

"Until now we’ve been maintaining a liability," says Sentech executive Johan Raath. Some components in Sentech’s current, analogue TV broadcast network date back to the early 1970s. Simply finding spare parts to maintain it has become difficult, he says. "SA is facing the very real possibility of a television black-out."

Sentech estimates that the move to digital TV will cost about R600m, but Raath is adamant the benefits will outweigh the costs. The R600m estimate excludes the cost of the digital set-top decoder boxes that consumers will have to buy. These boxes are required to display digital signals on TV sets, most of which are only capable of receiving analogue signals. The set-top boxes cost about R500 each, a price tag that could prove to be prohibitive for many of SA’s estimated 7m TV households.

Government has not decided whether it will subsidise the devices. It must also decide whether to provide incentives to electronics companies to establish set-top box manufacturing facilities in SA.

For broadcasters, though, DTT is a no-brainer: the operating costs are much lower than for analogue broadcasting, not least because digital transmitters use significantly less electricity. Spare parts are also cheaper and more readily available.

The biggest benefit of DTT, though, is its "spectral efficiency" – digitally broadcast TV channels use less radio frequency spectrum. Once SA has moved to DTT, the airwaves will be able to support up to eight times as many standard-definition television channels using the same frequency that is currently needed to broadcast just one channel.

DTT could also pave the way for the introduction of new regional television stations. Already, the SABC has plans to launch two new regional TV stations – SABC 4 and SABC 5 – which will broadcast exclusively in indigenous African languages. But broadcasting regulator Icasa could give the go-ahead for many more such regional ventures, says Raath. "You could have educational or Aids information channels, for example."

The national upgrade to DTT is expected to take three years. Implementation will begin later this year, Raath says. Sentech’s 10 largest transmitters – which are also the oldest and cover 70% of the population – will be upgraded first.

There will then be a period of "dual illumination", where both digital and analogue networks coexist alongside one another. Government must decide how long this will last. "Dual illumination is expensive and unwieldy," says Raath. The UK recently reduced its period of dual illumination from 15 years to 10 years.

Further down the line, DTT will allow for the introduction of terrestrial high-definition television (HDTV), where the broadcaster transmits a wide-screen picture (16:9 aspect ratio) of about twice the quality of a standard-definition transmission. Whether SA gets an HDTV channel will have to be a policy decision, as many standard-definition channels could be launched in the same frequency needed to broadcast one HDTV channel.

Whatever is decided, the SABC is already investing in HDTV broadcasting technology ahead of the 2010 soccer World Cup . It has bought an HDTV outdoor broadcasting facility from Sony. The Federation of International Football Associations requires the host broadcaster to provide HDTV signals, even if the host country has not yet begun terrestrial HDTV broadcasts.

The HDTV project forms part of a huge technology upgrade at the SABC, led by technology MD Sharoda Rapeti. The national treasury last year promised the state broadcaster R700m in funding over the next six years. It will use the money to build new networks, replace its ageing analogue infrastructure, upgrade its back-office systems and install new post-production and TV facilities.

Even if SA doesn’t get a terrestrial HDTV channel, there is a chance that MultiChoice will oblige with a high-definition channel on its DStv bouquet in time for the World Cup, says CEO Nolo Letele.

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DIGITAL GOES THE AERIAL ROUTE