The Big Question: Is the analogue/digital switchover destined to lead to chaos?

Why are we asking this now?

An influential parliamentary committee yesterday warned that there could be a major public backlash against the Government if it persists with plans to switch Britain's radio broadcasts exclusively to digital radio. The House of Lords Communications Committee also publicly expressed doubts that ministers can realistically carry through their plan to switch off the FM broadcasts – through which most of the population listen to the radio – by 2015. More than 90 per cent of the population listens to the radio – on average for 22 hours a week. Two-thirds of them listen on FM wavelengths. Government plans would mean that 100 million radio sets would have to be thrown away.

What is digital radio?

Digital radio converts sounds into computerised pieces of information and then compresses them before they are sent out from radio transmitters. Radio sets then pick up the signal and decode it, converting it back into sound. Because digital signals are compressed they take up far less space than the analogue FM/AM technology. So more stations can be broadcast using the same airwaves.

Digital broadcasts began in the UK in 1990. Britain now has the world's biggest digital radio network, with 250 commercial and 34 BBC radio stations broadcasting from 103 transmitters.

Will the change definitely come?

That's the plan as outlined in the Digital Economy Bill in the last Queen's Speech. To achieve it, the Government is pushing manufacturers to offer DAB radios for under £20 and asking the car industry to make all car radios digital by 2015.

But they have said that the "digital upgrade", as they call it, cannot happen until at least 50 per cent of all radio listening is being done on DAB (Digital Audio Broadcasting) the particular digital system Britain has chosen. It is not clear whether it will match the £800m fund of public money set aside for the digital switchover on television.

What was wrong with the old system?

The FM airwaves are full and there is no room for new stations. FM is also susceptible to interference, while digital is resistant, and accessing stations on digital is easier. But it is also susceptible to breaking up where the signal is not good. So it can be clearer than FM but more intermittent. Some areas with good FM signal – 99 per cent of the country – have a poor DAB one.

Why aren't DAB signals in the UK of the highest quality?

The reason for that is that authorities decided to maximise the number of stations, rather than improving quality. The MP2 compression format used by the BBC makes the sound quality on DAB inferior to FM because more stations are being squeezed on to the bandwave than were originally planned. So you get quantity rather than quality, and that's not what a lot of people want. Many listeners are buying the new radio sets but only using them to receive their old FM favourites. One survey showed that 94 per cent of listeners are satisfied with the radio they currently listen to.

On quality, Radio 3 listeners have objected to the drop in sound quality and the BBC have been forced to increase the bit-rate of the transmission of Radio 3 from 160 kbit/s to 192 kbit/s. There are two other problems. DAB radios use more mains or battery power than FM radios. And they have a two-second time delay, so time signals are not accurate.

So are people buying DAB?

Slowly. They came on to the market in 1997 as car radios costing £800. Hi-fi tuners costing up to £2,000 came two years later. It wasn't till 2002 that the first DAB was sold below £100. Currently they cost at least £40. Today 21 per cent of radio listening is digital – half on DAB and half through the internet. Only 28 per cent of radios sold last year were digital. The rest were bought by people who presumably did not realise their new purchases will officially be obsolete in just five years.

But they have not exactly been encouraged by the BBC's recent plan to junk two of its digital-only stations – 6 Music and the Asian Network – and the cost-cutting decision last year by Channel 4 to abandon plans for an ambitious digital radio service to rival Radio 4.

What about car radios?

Some 20 per cent of all radio listening is done in cars. But only one per cent of vehicles can receive digital stations. The automotive industry has dragged its feet, partly because it is not clear which digital technology would eventually win out, and partly because only the UK has been keen. The result is that at least 20 million older cars will need to have converters fitted, at the expense of the owners, if the FM signal is turned off in 2015.

Why can't we have both?

We could. Analogue and digital transmissions can co-exist without interfering with one another. Many people want the two to co-exist so DAB becomes an additional platform rather than a replacement one. We could certainly have a much longer transition than a 2015 switch-off suggests. But the government wants to auction off the FM airwaves off for other uses by telecommunications industries who see new mobile phone, Wi-Fi and other money-making potential.

Will digital last?

Not necessarily. Some countries want to introduce DAB+ which offers better sound quality than the DAB standard used in the UK. DAB+ could make DAB obsolete. If DAB+ came in many DAB radios would be unable to receive it, though some could be upgraded. Critics fear that DAB could then go the way of the Betamax Video Cassette or Quadraphonic sound.

Or DAB technology could be leapfrogged by wireless routers using the internet. The quality of the digital radio signal received through television sets with cable connections is higher than that through DAB radios – which is why Which? magazine recently warned consumers that they might not get the same performance from a DAB radio as they heard in shops which had them cabled up. Almost half of digital listeners already listen through the internet. Of the other half, 41 per cent listen through their television.

Market leaders like Bose have feared for some time that DAB could have a short lifespan, which is why they are still refusing to build it into their revolutionary Wave radio, offering DAB only as a plug-in. They are making Wi-Fi soundlinks, too.

What will happen to the old radios?

Between 50 million and 100 million portable, bedside, clock or hi-fi analogue radios – all perfectly functioning pieces of equipment – will need to be binned if the compulsory switchover goes ahead in five years. The environmental impact would be significant, and the public outrage considerable. Which is why so many people are arguing that the case for the radio switchover has not been made.

Should our FM radios be switched off in five years?

Yes

*Our cash-strapped government will be able to sell off FM airwaves to the telecoms industry.

*Digital offers a far greater choice with nearly 300 stations broadcasting in Britain.

*The amount of DAB coverage and the quality of signal should be better by then.

No

*The sound quality on FM is superior than the compression formats used with digital.

*What is the point in making roughly 100 million perfectly good, working radios obsolete?

*DAB radios currently use more mains or battery power than existing radios.