Digital satellite television signals are radio waves, which are also used to broadcast other types of signals.

The shift to an on-demand world must be completed by 2012, when the final analogue television signals are switched off, he said.

That's because the airwaves needed to broadcast television signals belong to everybody, not just you.

As a matter of broadcast engineering practice, 4:3 analogue television signals will always pose the most problems with broadcast safe compliance.

A transponder received and transmitted voice and television signals and scientific data.