tv transmission

Satellite and Terrestrial Television Transmission

Insightful Comparison Between Satellite And Terrestrial Transmission Of Television

Digital Satellite TV

The majority of digital satellite broadcasting uses a standard called DVB-S (Digital Video Broadcasting – Satellite).  It became a commercial reality in the UK in 1998 when BSkyB launched its “Sky Digital” service, renting space on an Astra satellite.  At this point receiving equipment was expensive, so viewers signed up for a subscription with BSkyB, and were loaned the necessary receiving equipment.  Most of the services were encrypted, so that only paying customers could watch them. 

digital satellite tv

Since then, many other broadcasters have started broadcasting using the same standards using satellites over the UK, including the BBC.  Many of the services are not encrypted (including many audio-only services), so they can be received without any subscription.  The price of receiving equipment has reduced so that a decoder and dish can be purchased new for around £200.

There are around 78 free audio channels available to UK listeners with their dishes pointed at the Sky Digital satellites.  Listeners with Sky Digital-specific receivers can see details of the current programme on each station.  No matter where you are in the UK, you will receive the same set of services, including these in non-English languages and intended for particular localities.

Most digital satellite receivers don’t have displays, so even if you use your Hi-Fi to play the sound, you need your television on to see what station you’re on.

Digital Terrestrial TV

Digital Terrestrial TV in the UK uses a standard called DVB-T (Digital Video Broadcasting – Terrestrial).  It was launched in the UK in 1998 by a consortium called On Digital, using space between the existing analogue TV channels.  In DVB, a set of channels is broadcast as one signal called a multiplex.  On Digital operated three of these multiplexes, the BBC operated one, and another consortium called SDN operated a fifth.  In a similar way to Sky, many of the channels were encrypted, so viewers were invited to subscribe and borrow a decoder.  On Digital was later renamed “ITV Digital”, and finally went out of business in 2002.  The problem seemed to be that they were supplying too few channels at too great a cost.  There were also reception and piracy issues.

terrestrial tv antenna

A new consortium called “Freeview” was awarded the licences given up by ITV Digital, and began broadcasting a set of free channels.  The BBC and SDN continued to operate their multiplexes.  All three operators added audio-only services to their line-up so that in most places around 21 stations are available.  Since Freeview’s launch, some much cheaper receivers have become available.  High Street shops are now selling them for as little as £60.

It’s not usually possible to receive these services without connecting your receiver to a TV aerial on the roof .  Through this limitation, it’s obviously impossible to receive them on the move.

The same audio services are available across the UK, except for 6 of the BBC’s regional services.  Whilst it’s technically possible, no other local or regional stations broadcast on Freeview.

As with digital satellite TV, receivers don’t have displays, so even if you use your Hi-Fi to play the sound, you need your television on to see what station you’re on.

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