Digital radio is currently undergoing separate trials in Sydney and Melbourne, and digital radio receivers that allow you to tune in freely are now available to the public. Two individual outfits have established reference sites for technical testing and market research, and to demonstrate the core and expanded capabilities of digital radio.
The Sydney metro trial is being con---ducted by DRBA - Digital Radio Broad-casting Australia (www.digitalradioaustralia.com.au). This con-sortium was formed by Commercial Radio Australia and stations taking part in the simulcasting trial. These include WS-FM, Nova 969, 2GB, 2CH, 2UE, 2DAYFM, 2KY, 2SM and a DRBA test station, in addition to two stations each from SBS and ABC (Classic FM and ABC DiG radio, in the case of the latter). ABC DiG radio is also available as an Internet stream (www.abc.net.au/radio/digital).
After months of interference testing, the Sydney trial started on 17 December 2003 and is transmitting on Channel 9A on the VHF band.
However, those with digital radios need only to auto-scan or tune in to ensemble (multiplex) the 9A, 9B and 9C channels. An ensemble contains not only groups of stations with audio, but also other program-associated data as discussed later in this article. Each station has about 256Kbps of bandwidth to manage: generally, 192Kbps is used for actual audio, and the rest for data that must be related to the core content in order to meet current government legislation. Talkback station 2GB, for instance, isn't allowed to create a music channel, but could theoretically split the signal into two channels to cover two football games simultaneously.
DRBA is also planning a Melbourne trial, but the city has been Broadcast Australia's (www.broadcastaustralia.com.au) testing ground since November 2003. Featured are the afore-mentioned SBS and ABC stations, plus ABC news radio, Sport 97 (3UZ), World Audio Radio 2, and community radio station 3RRR. Future community radio stations include 3MBS, 3RPH, 3PBS and 3ZZZ. Melbourne digital radio owners tune to ensemble 9C.
First-generation digital audio broadcast (DAB) receivers (or digital radios) were criticised for lack of features and cost, but they did provide access to the near CD-quality, noise-free audio associated with digital radio, and could easily auto-scan and switch between stations, removing the need for fiddling with tuning dials. Devices now available and supported in Australia offer more improvements, usually including at least two or three lines of scrolling dynamic text for information related to a broadcast. This is known as Dynamic Label Segments (DLS), and can include what's on now and next, sports and racing results, the latest news or weather details, Web site information, phone numbers and more.
Coming up next
Future versions are expected to allow interactivity and something that has been termed 'vision radio' - colour displays for artist or album cover images, and even low bit rate MPEG-4 video. Basic time-shift recording and temporary data storage is also anticipated, so you could click on a 'tell me more' button to see and hear more about an advertisement or artist. Then there are convergence devices combining MP3 functionality or even digital radio in mobile phones. Depending on the outcome of regional trials, this could be only seven to eight years away.
Highlighting the anticipated demand for these digital devices, Harvey Norman launched a digital radio display centre in its Auburn, Sydney store in May, purely to showcase some of the first personal and in-car receivers. The retailer has agreed with the industry not to sell the receivers themselves because digital radio is still in its testing stages and the final standard that Australia will adopt is not yet confirmed. However, digital radio receivers are now available for purchase (with the same caveat) from vendors such as PURE Digital (www.pure-digital.com) and Blaupunkt (www.blaupunkt.com.au), and distributors including Grundig Australia (www.grundig.net.au) and Canohm (www.canohm.com.au).
Many in the DAB industry feel that the Eureka 147 platform used for Australian trials eventually will be given the green light by the Australian Government. This standard is already used in the UK and is currently being trialled by Singapore, China, Malaysia and Korea. It's therefore probable that Australia's less expensive receivers will be manufactured in such countries. The US and Japan are implementing their own customised standards - as they have done with digital TV.
We tested the Sydney trial that's currently transmitting in MPEG-1 Layer 2, mostly at 192KHz in stereo or mono. The quality improvement was noticeable, although a garble-like distortion occurs when you begin to lose signal.
Remember that you need a hardware digital radio or DAB PCI-tuner card for your PC in order to pick up digital radio. Digital TV-tuner (DVB-T) PCI-cards and TV set-top boxes pick up limited digital radio: SBS and ABC services, and various Parliament audio streams. Also, don't confuse commercial digital radio with Foxtel Digital's 30 Air brand digital streams or Internet radio streams available to programs such as Winamp (on this month's cover disc). If you're waiting the trials out, however, such alternatives may be worth accessing.