You probably have an analogue LNB (the electronic bit on the arm of the dish) so that will have to be changed. On the house I bought the LNB didn't work so I had a "digital ready" one fitted at about 70 quid including call-out charge, LNB and aligning (a simple enough job but not without the right test gear).
Then there is the receiver.
I got a second-hand analogue set but after a year I notice channels are going blank (assume digital) and radio stations are disappearing.
Mind you I found R4 was always noisy compared to my super all-band radios.
Still until Eurosport stop screening the motorbike (& sidecar) races I will stick with analogue because when it rains or snows (enough) the signal degrades until all you see is "snow" but with digital there is a threshold and you loose everything, long before you get fed up of a poor signal!
"No signal" has "no quality"!
spot the electronic engineer!