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Commentary: DRM Offers Digitization Key

The open all-band digital standard offers solution to help local stations digitize

Ruxandra Obreja is Digital Radio Mondiale Consortium chairman. Contact her via email at: [email protected]

LONDON —Digital Radio Mondiale could be the obvious alternative to the call for delaying the digital switchover coming from a group of smaller commercial stations in the United Kingdom, the most successful digital radio market in the world to date.

This debate has surfaced as the country’s culture and communications minister, Ed Vaizey, is due to make an important statement at an event in London in December. Expected initially to be an announcement of the digital switchover date for the U.K., the pronouncement, according to the Head of Digital Radio UK, might be much weaker. “I expect the minister, said Ford Ennals, in a recent BBC interview, “to say it’s the right policy but that the industry and the consumers are not ready yet.”

This “difference of opinion on the pace of change” may have been precipitated by the strong opposition to an enforced digital radio switchover by the group of 80 smaller commercial stations representing about 6 million listeners.

DAB, a Eureka 147 open standard, devised by and favoring major radio players was introduced in the U.K. 14 years ago. Of the 101 to 117 million radio sets in the country about 15 to 19 percent are digital. The stations opposing a switchover announcement think that their group, about 100 smaller commercial stations, would be severely disadvantaged due to an absence of transmission capacity or unaffordable transition costs.

These smaller players fear they would be relegated to an analog second tier of broadcasting. And even if they were to go digital, they worry about the high costs of transition with loss of coverage (due to the multiplex nature of DAB) and consequently the loss of audiences and advertising revenue.

In order to offer a solution to these stations, which have been voicing their concern for some time, a hastily put together test, endorsed by the U.K. regulator Ofcom, was published in the summer. It details a low-cost localized transmission solution, probably best suited for demonstrations and events rather than as a long-term viable solution for smaller stations.

The small-scale DAB test should be followed by further investigation but even if such a further study were to be conducted, the issues of cost, coverage and frequency availability in band III would probably be insurmountable barriers.

The “group of 80” dismiss the small-scale DAB solution and argue that a “one-size fits all” approach risks leaving listeners behind and jeopardizes the future of smaller local stations. They ask the government not to hurry, to let listeners and broadcasters set the pace of change, especially as the vacated AM and FM frequencies are mainly suited for broadcasting and there is no plan for their future deployment.

The DRM Consortium offers an immediate solution that could help the local stations digitize, give a new lease of life to AM stations, keep the VHF and AM bands gainfully employed, provide an alternative pathway that would make digitization in the U.K. and elsewhere a reasonable solution. It is called DRM, the only, open all-band digital global audio broadcasting standard.

In a critique of the Ofcom “small-scale DAB study,” the Consortium addresses indirectly the main concerns of the group of 80 on coverage, costs and spectrum.

In the clear report of the small-scale DAB study the author acknowledges that “DAB is currently an unsuitable replacement technology” for local FM stations. One reason might be the issue of spectrum availability in Band III and its efficient use. A DAB or DAB+ channel is always 1.5 MHz wide and in less populated areas a multiplex might contain as little as one program: pure spectrum waste.

A DRM+ channel with a similar performance is only 100 kHz wide (half as wide as an FM channel.) The efficiency is even clearer when compared with DAB.

As a DAB multiplex can carry up to 16 programs, where the full multiplex is not fully utilized it becomes very inefficient. This means that using DRM+ instead would require about 10% of the DAB radiated power.

It is widely accepted therefore, that, when replacing FM transmissions on a one-for-one basis, a DRM+ transmission needs much less spectrum and energy than FM in order to provide the same high audio quality.

The spectrum needed for each program stream is about one quarter of that required for an FM sound broadcasting channel. These advantages have been confirmed by DRM+ test transmissions carried out in Edinburgh by the BBC and the DRM Consortium and also in other European countries such as Italy, Slovakia, France, Norway and Germany.

It is clear from all the tests that DRM+ can be configured in different ways to offer greater flexibility than FM or DAB broadcasting.

As stressed in the paper sent to Ofcom by the DRM Consortium, the most attractive advantage of the DRM system for switchover purposes is that transmissions are maintained on the current model of a single transmitter per service aerial.

Thus, listeners can be assured that their favorite programming, whether national, regional, local or community based will continue to be available. Moreover, the switchover can be phased in over a period of time according to individual decisions on a per transmitter and area basis, if necessary making use of the simultaneous dual transmission possibilities offered by DRM.

The Consortium supports the announcement of a switchover date. It sees it as absolutely necessary in order to galvanize the broadcasters and the industry, while creating a realistic expectation for the listeners that they would be better served and have more choice. But the digital solution chosen has to satisfy all stakeholders.

There are already DRM/DAB/FM chips (including HD, too) and the premise of multi-standard receivers is now real.

Digital radio needs to combine compatible standards according to national needs in order to present broadcasters and listeners with a workable and desirable “digital radio.” Maybe the time has finally come to have a fresher, more holistic, non-partisan and pragmatic assessment of how best to use one or several standards to achieve digitization and change.