Making the switch to digital TV

By Spencer Kelly Click presenter

The town of Whitehaven in Cumbria has become the first place in the UK to switch off the analogue transmitter delivering BBC Two.

But the channel is a waste of space - and it takes a brave man to say that at BBC Television Centre - but it is, and so are all the other channels.

Whitehaven is leading the UK's digital TV switchover

TV pictures have been broadcast as analogue radio waves for decades, and they take up a lot of room in the radio spectrum.

Newer digital television is a much better broadcast system which is why every country will eventually switch off its analogue transmitters and switch over to digital.

Digital TV promises a much richer viewing experience. Cleaner pictures with no interference or ghosting, programme listings, football from whichever angle you choose, interactive services, gambling and many more channels efficiently packed into the space occupied by just a few analogue ones.

The first countries to switch off all their analogue transmitter masts have been Luxembourg, the Netherlands, Finland and Andorra.

In the UK all analogue transmissions will have ceased by 2012 - if you want to watch TV after that, you will need a digital TV receiver.

There are several ways to get digital TV depending on how much you want to spend and how far into next-generation TV you want to get.

DIGITAL TERRESTRIAL

Here in the UK, the most common way is to receive our TV via a terrestrial signal, broadcast from masts around the country and received through rooftop or set-top aerials.

It is these transmissions that are being switched off in the coming years.

Digital terrestrial TV reaches your TV set via an aerial

Now there is a good chance that you will already be able to receive the replacement digital terrestrial signal through your existing aerial.

All you will need to buy is a digital receiver - a Freeview box, or a new digital TV set with a digital receiver built in.

About 73% of the UK is already covered by the digital terrestrial signal, and that will grow to 99% by 2012.

Richard Lindsay-Davies is director general of the Digital TV group - an independent organisation which is facilitating the digital switchover in the UK. He said: "One of the key parts of digital switchover is that you not only have to switchover your main TV you have to switchover you second, third, forth TVs and your video recorders as well.

"Terrestrial makes it slightly easier to do that because you can take one signal in through an aerial and easily transmit it throughout your whole home and you may be able to pick it up on a set top or television top portable aerial as well.

"That's not to say that you can't retransmit from the other platforms but it is slightly more complex and may end up costing you more."

You can even get digital terrestrial receivers for your PC. Just plug it in, and away you go.

Freeview may be the most accessible, but it also gives the most limited service.

It shares the radio spectrum with many other services - radio, wi-fi, taxi cab and therefore the bandwidth available is limited, and so is the number of channels it can carry.

That said, in the UK we have about 94 TV and radio stations available which is still considerably more than on analogue.

DIGITAL SATELLITE

For those who want a wider choice, there is the extra-terrestrial option. Out in space hundreds of satellites beam TV to countries around the world.

To get digital satellite TV, along with your digital receiver, you will need a satellite dish.

"The capacity available on digital satellite is much greater than that available on terrestrial for various technical and physical reasons," said Mr Lindsay-Davies.

"This means that there are hundreds rather than tens of channels available on satellite.

"Those channels not only come off the one satellite that's pointed at the UK, but it's possible that other services broadcast throughout Europe could also be picked up on the satellite dish."

In order to enjoy satellite, you will either need to pay a Sky monthly subscription or a one-off fee for a Freesat setup, either from Sky or from the BBC when its service launches next year.

DIGITAL CABLE

Our next digital platform takes us from high above the earth to deep under it. If you can get cable to your house you are opening up a direct link to and from your service provider, down which you can get all kinds of lovely stuff.

Wire, or even better, fibre optic cable is much better at transmitting data than air. And the experts we have spoken to agree that the amount of data - the bandwidth - you can get down a good quality digital cable should be higher than any other digital TV platform.

Around 84% of households in the UK currently access digital services

In theory, this means the most channels, and the most extra services.

Also, the direct line back to your service provider should allow full on interactive services like games and shopping too, along with video on-demand - programmes streamed from your provider to your receiver when you want.

Yes, cable sounds great, assuming you can get it in the first place.

I say should, because in some countries, including the UK - that is not the case.

Roy Brooker is the principal scientist at Intertek, which tests equipment including digital TV kit for Which? magazine and other consumer testing organisations.

"Cable in the UK started rather shakily when a very large number of companies were given licences for different areas and over time this has come down to just one provider, Virgin," he said.

"But the legacy is that cable in the UK is mainly restricted to built-up areas. On the other hand the cable networks are going digital and are able to provide much better interactive services so it's possible in the future that we will see more interactivity from cable but at the moment it doesn't seem to be providing strong competition."

Virgin Media say that although they'll continue to extend their fibre network to new urban areas, they have no plans to extend it to rural areas.

It does however plan to makes its service available over an internet connection.

IPTV

Even if you cannot get dedicated cable to your home, it is already possible to get video on demand and live TV over your broadband connection - if it is fast enough. It is called IPTV. In the UK, the two IPTV services are BT Vision and Tiscali TV.

It is worth noting that although IPTV stands for Internet Protocol TV, that does not make it web-TV.

Mr Richard Lindsay-Davies insisted the two are very different.

"With web-TV you're not guaranteed a quality of service, you may get a little 6" by 6" picture in the centre of your screen where as IPTV is a guaranteed quality of service," he said.

"It appears just as if it's coming through terrestrial, normal cable or satellite, but it does have all the options of good interactive TV, video on-demand, and exciting new services that they can bring by having a one-to-one link between the consumer's home and the broadcaster."

QUANTITY VS QUALITY

So what about this claim that digital TV gives us better pictures than analogue?

No interference, no ghosting - great. But is there anything they are not telling us?

The truth is that digital TV picture quality is variable. How much detail there is in a picture depends on several factors, including how much is going on in the shot and how much bandwidth a particular channel has paid for - too much action and too little bandwidth and the whole thing could turn into a blocky mess.

"The problem with fast moving pictures, particularly football matches, where the camera panned, the picture went blocky," said Mr Brooker. "Also if the camera stayed stationary on the grass it was beautifully clear, but if it panned the grass became a snooker table.

"This is a side effect of the digital compression. The only way you can overcome it is by broadcasting fewer channels within the frequency band. It's a balance between quantity and quality.

"You have the choice with digital television - a large number of channels at no better quality than analogue, even more at lower quality than analogue, or a few channels at better quality."

Of course high definition TV is on its way, promising higher quality pictures, and less detail loss. But the question remains - will the broadcasters make sure they buy enough bandwidth to give us the full quality we have been promised?