Why DAB; what is it?
From the user's perspective, the reasons for opting for DAB now are because it sounds so good and is so convenient. The sound isn't better than you get from a good FM hi-fi tuner connected to a decent set-top aerial but on a portable that uses a small aerial, it's far better than the stations you'd normally receive, not just on LW and MW but on FM, too.
From the government and broadcasters viewpoints, DAB is also a good thing since each station takes up less bandwidth than its analogue counterpart, allowing better use to be made of what is, afterall, a limited range of available radio frequencies - the more so since broadcasters now cram in more stations in each multiplex than was originally intended.
Unfortunately, that means that the quality has been reduced from that of the original spec defined in the Eureka 147 Digital Audio Broadcasting system. And that's why a good FM tuner will always beat a good DAB tuner if both are fed good signals.
In terms of convenience, there were two features that we appreciated most when using the Dualit, our favourite being the way that you can jump directly from channel to channel with each small turn of the tuner knob, rather than having to move up or down a frequency range until you hit the next channel - as happens with analogue radio, though not those with auto-tune, but these will often jump past weak stations. We also liked having available the information that can be carried along with the radio signal and displayed on the radio's LCD panel.
We're not so keen, though, on the fact that the Dualit radio's display - as with all the (few) DAB radios we've seen to date - doesn't let you see all or even most of this information on a single screen. Instead, with the Dualit, you have to cycle through seven screens of information, each of which stays in place until you move to another. Not all stations make best use of DAB's information-carrying capability but when they do it's very neat.
The BBC does a good job, so we'll use one of its stations, Five Live, to illustrate the point. All screens show the station name but on the first, this is accompanied by a ticker-tape readout describing the current programme. Next up, the LCD will show a description of the station type. In the case of Five Live, that's News - others include Sport and Pop Music (you get the idea). After that, the display shows the multiplex type (BBC National DAB, in this case) and the fourth screen carries the time and date (in UK format).
The fifth shows the channel number and frequency (12B/225.64MB for Five Live) and the sixth displays the data rate - 80kbps in this case - and whether the station is mono, as Five Live is, or stereo as seems to be the case with all music stations. And stereo, of course, requires double the bandwidth of an equivalent-quality mono broadcast. The last screen shows a read-out of signal errors, numbered from 0 to 99. Zero to 20 is good, 21-40 is borderline and 40-99 means move the radio to another location in the house or, if that doesn't help, move home.
Numerous DAB products are available in the UK, ranging from personal radios, through table-top models - such as the Dualit (and many less expensive offerings) - up to tuners sold with, or for use alongside, hi-fi systems.
Note - July 1, 2006, 3:30
This page requires further editing. References to Digital Radio Mondiale and its possibly-competitive relationship with DAB have temporarily been removed but will be restored when some errors of fact have been corrected.