My signal to my digital tv is not nice. do i need a new ariel?

We have a digital box in a room at the back of the house and reception is fine but is hardly nice in our room at the front. someone has told me that the signal is "converted" to digital so a new ariel will not make a difference. however, someone else has said that there are special digital ariels available.plz could you offer me some advice?
Answer
Look for digital boosters, to connect to the existing system. or get sky, which never fails.