Basic understanding of the Switchover
At the minute TV transmitters (e.g. Belmont, Emely Moore, Sheffield) all transmit an analogue (terrestrial) signal plus a digital signal also known as Freeview to your TV through your aerial.
When the digital switchover takes place in your area it will mean your analogue/terrestrial signal (e.g. Channels BBC1, BBC2, ITV, C4 & C5) will be switched off. In order for you to still receive these channels and continue to watch your TV you will need a TV with built in Freeview or a Freeview Set Top Box. You may require an aerial upgrade but this is dependant on the condition of your existing aerial and the area that you live in (due to different area signal strengths).
Areas that cannot receive Freeview through their TV aerial due to living in a very poor signal area may purchase Freesat. Freesat is similar to Freeview except you receive signal through a satellite dish and you will require a TV with built in Freesat or a Freesat Set Top Box.
I hope this has helped with the basic understanding of the switchover but if you do have any further questions then please call me.