It's Digital Audio Broadcasting. Just like with television, there is a digital version of radio.
The theory of it is that the sounds quality is better - with digital it is pretty much on or off rather than crackling and such like.
The reality doesn't seem to quite match up to this. I've found that the sound quality is good, but only when you get a good signal. Apparently this is because the transmitters wont be able to go up to full power until analogue television is discontinued.
If you do go for DAB beetroot I'd recommend an outside aerial (many tv masts come with this option so you may already have the ability). A good choice would be a radio such as the Evoke Pure - this allows you to listen via DAB, FM and the internet as well so gives you a lot more content (BBC podcasts and listen again for example). I bought one for my mother last year and she loves it, and when the DAD signal is bad she listens to the internet version. She also likes the fact that you can add all of your channel presets via a web interface.
Hi Beetroot, I'm in the Grange Road area and have a really good DAB signal without an outside aerial. I actually have two DAB radios, both Pure Evoke models but one designed to be portable. The one which isn't portable I have near a window and find I don't even need to extend the in-built aerial. The one which is portable moves between the bathroom and kitchen - neither room has a window and I find I do need to extend the in-built aerial. However, this was also half the price of the non-portable model so that may explain things! I am a big fan of DAB - lots of channel choices (in this part of the world, anyway) and at the touch of a button: BRILLIANT. I'm getting one for my car next.
I live on City Walk (Morocco street/Long Lane) and don't get a great DAB signal. I'm using the indoor aerial that came with my radio and it really does depend on where I place it plus some other unknown factors - weather, furniture, what other electrical devices are switched on...?
On a good day I get most ofthe DAB stations listed on my radio. On an average day, the majority of them sound 'bubbly' like they are being listened to underwater. On a bad day I get around a quarter of the stations. The BBC ones are consistently the strongest signals. On abd days, I switch to FM.