It difficult tell based on the information that you have supplied. The box isn't a DV3, that is the logo of Digital Video Broadcasting (the last character is a stylised upper case B) and to don't say when this fault occurs.
However assuming that it is a simple Freeview Receiver and the problem occurs when you are trying to watch a digital TV channel, it almost certainly your aerial causing it.
Check the connections and alignment.
T, August 2009
