Steve Ahern explains Digital Radio
Steve Ahern explains Digital Radio
At some recent conferences I have been asked to explain the success of digital radio in Australia. I am currently writing a chapter on it for the 3rd edition of my book, Making Radio, which will be out next year, but until you read that, here is a summary of what digital radio is all about, and how it has been introduced in Australia, taken from an article I wrote and some recent conference presentations.
It has been a long time coming, but Digital Radio is finally here in Australia. I first heard about digital radio when I worked at the ABC twenty years ago. It was supposedly just a few years away then. Just a few months ago, August 6 2009, digital radio was finally launched at a series of industry wide outside broadcasts around the country (see photos). Has the wait been worth it?
Definitely yes.
In the intervening years since digital radio was first invented, the technology has been improved, and Australia is one of the first countries in the world to reap the benefits of more efficient delivery of the digital transmission system using DAB+.
In those intervening years though, competing technology has also been developed and it is possible to stream audio over the internet and via WiFi, so even though radio has improved, it now has even more competitors to content with, all using the digital platform.
Let’s take a step back and understand how digital radio works.
Digital radio works in a similar way as streaming or downloading audio on the internet. A carrier (your internet connection) delivers bits and bytes to your computer that are encoded in a certain way, perhaps as mp3 files. When those bits and bytes arrive at your computer they are decoded and reassembled in the right form. Some of those encoded digital streams make audio play out of your computer, others bring you pictures or word documents, or whatever you have downloaded.
Digital radio uses the same principle of digital encoding, but instead of being delivered to you through broadband from your internet service provider, it is carried by radio waves.
The ‘encoding’ for streaming audio, based on MPEG layer 2 algorithms, is more sophisticated than mp3 encoding and can deliver better quality audio. Because many more bits and bytes can be carried, digital radio is much more spectrum efficient than the old analog form of radio. And because computer processor based digital radios can correct errors better than analog radios can, the signal is more robust and clearer in most cases. Digital radio quality is light years better than AM, and better than FM quality, while using much less bandwidth.
How many bits per second a station chooses to use determines the quality of its signal. The improved form of digital radio used in Australia, called DAB Plus (DAB+), can deliver twice as many stations as the original form, DAB, used in the UK, Europe and elsewhere. Many countries are now examining the possibility of upgrading to the DAB+ standard and are looking at Australia to prove that the new improved system works. So far they are concluding that it works very well.
Most stations in Australia are getting good FM quality signals at a data rate of 48 kilobits per second, one third of the bit rate used to deliver similar quality in the older system.
Every licenced station is allowed a total of 128 kilobits on the That means stations can do more with the spare capacity they have after streaming their main audio channel.
Let’s do the maths. 128 kilobits, minus 48 kilobits, leaves about 80 kilobits to play with. You can decide to put up a second channel with this extra capacity, or you can transmit text, such as name of artist and song title, or you can transmit still pictures, similar to a powerpoint slide show. Or you can mix and match bit rates and do a bit of everything.
Austereo is doing just that with Radar Radio, a new music channel playing unsigned bands. DMG has two channels up, a smooth jazz style station called Koffee and a dance music station called NovaNation. ABC Radio has launched three new music channels, Dig, Dig Jazz and Dig Country. Because there is still more bit rate capacity, even after launching new audio channels, companies are also able to put up simple text and slide shows to enhance the consumer experience.
Digital radio also uses shared transmission facilities, making it unnecessary for each station to own and operate its own transmission tower and delivering more cost effective, less power hungry, ‘greener’ transmission than analog.
The missing link so far in this explanation is the consumer.
You need a new radio to listen to DAB+. Your old analog radio will not pick it up.
The big question in the lead up to the Australian launch of digital radio was… will people buy new radios, which cost anywhere from $100 to $1000, depending on the sophistication of the unit you purchase?
A fair question and one which industry people were rightly sceptical about, especially since it took over five years to convince British consumers in any large numbers to buy new sets.
The good news is, in just a couple of months since full DAB+ switch on, retailers are reporting sold out stocks of all models of radio and are clamouring for suppliers to sell them more.
So far the news is good.
In a population of about 22 million people there are about 8 radios per household. Aussies love radio.
No one is expecting them to throw out their old radios, but the signs so far are that consumers are likely to buy at least one digital radio some time in the near future, then replace their old radios as they break year by year after that.
Which radio will they buy?
That will depend on their needs.
If I want a portable device I may buy a phone with a digital radio in it, or an mp3 player such as the iRiver, which is digital radio equipped and has a screen display.
If I want a car radio I may buy a Pure model that fits to my car in a similar way as a Navman and plays out through the car’s stereo system. It will give me screen updates of where the traffic jams are as I drive around, even when a song is playing.
For the bedroom, kitchen or office there are table models such as the Pure, Revo and Roberts models which have quality speakers and a variety of screen display modes.
For the HiFi enthusiast there are cheap models with digital audio outputs to deliver great quality to yor HiFi system, up to top end models that integrate with your 5.1 surround sound system. These models also receive internet radio through WiFi and can access songs stores on your home computer network too.
The last question is why?
Why go digital?
Why try to improve on Marconi’s technology, which is now over 100 years old?
The answer is all about the future. The future is digital.
You carry around a digital mobile phone, your mp3 player and computer are digital, so is your tv, your car control system and anything to do with the internet.
If radio were to remain analog it would be left out of all the new digital devices which are around now and are yet to be developed in the future.
More than that, the old analog spectrum is being compromised by fluorescent lights, garage door openers, can wireless door locks, WiFi internet and metal buildings. It is almost impossible to listen to AM radio in large city buildings these days and interference is only getting worse as time goes by.
There are other competing digital radio technologies, such as DRM and IBOC, and those too seek the same goals as the system Australia has chosen, DAB+. The comparative differences between these competing technical systems will have to be left for another, much longer article, because the discussion of the comparative merits of each system is very detailed and contentious.
Like digital tv and digital everything, digital radio is Australia’s investment in the future. We are innovating and leading the world radio industry into the future.
So far, so good. We watch and wait to see what the future will bring.
I have recently also written various articles abot digital radio on www.radioinfo.com.au. Search the news pages there for the most recent information on this new technology as it develops in Australia.