Digital TV

From DIYWiki
Revision as of 21:24, 2 January 2011 by NT (Talk | contribs)
Jump to: navigation, search

000932pv satdish.jpg

Contents

Introduction

TV in the UK is going digital. By the end of 2012 everyone (who wants to watch TV!) will need to have moved to one of the various digital TV platforms, as the existing analogue terrestrial TV transmitters are switched off. This article outlines some of the ways you can receive digital TV

When Do I Need to Go Digital?

Digital TV is the organization with responsibility for informing and advising the public about the digital switchover. They have a web page that gives the switchover date(s) for viewers in each television region

Ways to receive Digital TV

Integrated Digital TV

Many new TVs now incorporate a digital Freeview tuner (a so called Integrated Digital TVs or IDTV). These receive digital from an existing house TV aerial, if the quality of the signal's good enough. If you are buying a new TV it is worth checking that the tuner is indeed digital if you want it to work without the need for any extra equipment.

Set top box

A set top box (STB) is a generic term for any external box that decodes a digital TV service (from a conventional TV aerial, a satellite dish, or a digital cable service) and allows it to be displayed on your TV. The box is typically connected to the TV by either a SCART lead or a HDMI lead (and on rare occasions by a co-ax). Most of the Standard Definition (SD) converter boxes have a SCART output, and High Definition (HD) ones will typically also have a HDMI connection.

Personal Video Recorder

Personal Video Recorders or PVRs are more sophisticated set top boxes that are also able to record programmes. Programmes are usually recorded onto an internal hard drive these days - with a typical entry level recorder containing 160GB of hard drive space (or about 80 hours of recording capacity). Unlike video tapes or DVDs, a PVR can usually perform a number of playback tricks that were not previously possible, such as watching a recording from the start before it has actually finished recording - so called "chase play", pausing and rewinding a live broadcast etc.

The better boxes have twin tuners to allow recording of a different program to the one being watched or recording two different programs at once. The most sophisticated boxes offer advanced features like USB or Ethernet interfaces to allow connection to a computer or network.

The Internet

Another digital TV source is the internet. This can be accessed by computer and a growing number of games consoles and other media devices.

What's available:

  • BBC iPlayer: plays a selection of the most popular programs on demand, up to 7 days after airing. Plus it allows you to catch up on previous episodes of a series during the duration of the series being shown.
  • ITV, Channel 4, and 5 also have a similar service.
  • Various video viewing sites, eg youtube, google, allow viewing of user created video footage (and large swathes of unlicensed commercial content that has been illegally uploaded!)
  • P2P file sharing sites allow the (typically illegal) download of TV and movie content from around the world.
  • Masses of instructional videos on numerous sites, covering pretty much any subject you can think of.

Some of the main channel sites also allow "live" viewing of at least some of the content. (note that UK residents will require a TV license if using computer equipment to view or record live TV in this way)

To watch much TV over the internet on your computer will takes a lot of data, so a low download limit ISP account won't do.

Digital TV Performance

Performance of broadcast digital TVs in poor signal conditions is different to that of analogue. Where an analogue TV will suffer a progressively degrading picture (becoming ever more "snowy"), a digital picture will remain "perfect" until close to the minimum signal level, and then will begin to experience serious errors and glitches followed by complete loss of picture shortly afterwards. This is known as the digital "cliff effect".

This is most noticeable with the freeview DTV service, where an existing aerial installation is reused. A signal that may have resulted in a slightly grainy (but watchable if you are not too fussy) analogue picture, may not provide an acceptable DTV service.

Note that if your analogue reception is good, you'll usually be ok with digital, but if its less than great, then possibly not. (There are exceptions to this). The best advice is to try it and see before spending money changing your aerial. Simple Freeview boxes can be either bought very cheaply, or borrowed from a friend / neighbour etc.

Performance of Internet based services can vary greatly - from very poor to "ok" for real time streamed services, and poor to excellent for downlaoded services. Most online TV is only viable with a broadband connection offering at least 256kbps or better download speeds.

There is an instant performance test on Teletext/Ceefax page 284 that will often give a yes or no on whether your existing aerial setup is sufficient for digital TV. However the test doesn't take all the issues into account, and isn't always correct.

Consumer Test Reports

The government has commissioned Ricability, an independent consumer research organisation to provide consumer test reports on a range of Digital TV products, including aerials, set top boxes, DTV recorders and integrated TVs. Their results can be found here.

Content providers

Freeview

With freeview STBs or IDTVs, you buy the box/tv, but there are no ongoing costs, no contract, no subscription. You just plug it in to an aerial and watch.

Freeview and other DTV details

Freesat

A free satellite service offering a range of channels including some High Definition (HD) ones (assuming you have the right equipment). You will need to purchase the relevant Freesat STB or Freesat PVR, and possibly pay for a dish to be installed, however there is no ongoing charge.

Freesat details

Sky

Offer various pay per month and pay per view channels and programs. They also offer HD content on some channels (at extra cost)

Sky Details

Freesat from Sky

Not to be confused with Freesat described above!

You can purchase a complete Freesat from Sky installation package for a fixed price. This can be an attractive way of getting the hardware required (dish and STB) and the installation carried out as a bundled deal with no ongoing costs. You can also purchase a "Freesat from Sky" decoder card on its own for use in and existing Sky STB. Friends and relatives who have upgraded from ordinary Sky to Sky+ (i.e. a Sky twin tuner PVR), may have a "spare" ordinary Sky box you could borrow.

In addition to the Freesat from Sky option, you can also use any Sky STB without any decoder card in it. This will let you see all the Free to Air channels, but not handful of additional the Free to View ones you get with a decoder card.

Note if you initially subscribe to a Sky paid for service, and then stop, your existing decoder card should enable you to continue to watch all the Freesat from Sky content, including the free to view channels.

Freesat from Sky Details

About Free to View and Free to Air

Satellite services such as sky's typically include some channels that can be viewed on any suitable satellite receiver with no need for a subscription, or any form of decoder card. These are known as Free to Air services.

However there are also what are known as Free to View services. These require no subscription, but are encrypted and hence can't be viewed without a decoder card.

For details of which channels are included in which packages, along with which are free to air and free to view, see this list on wikipedia

Virgin

Pay per month and pay per view cable service, choice of packages with different channels included, and differing prices. Some customers can get cable TV at no extra cost if they also have other services from Virgin.

Pay per view content is also on all packages. This is PIN protected to prevent misuse, but the PIN code is crackable by very determined kids. The PIN can be changed any time.

Virgin Cable Details

Other

Another option (probably more for the TV enthusiasts, or people in search of specialist/foreign language programming), is to purchase generic digital satellite equipment. If having done this, you align the dish on the 28.2E˚ Eurobird Satellite Cluster (the one that carries the Sky and Freesat programming) you will in essence have something similar to Freesat as described above (although without the Freesat electronic program guide which makes finding out what is on far simpler). However there are other satellites that you can also "see" from the UK that are intended to provide programming to mainland Europe.

See Also

Personal tools