no picture with RF conection

[harrypickle]

i've just bought a SAGEM freeview set top box, when it is switched on for the fist time you get the welcome screen, the problem is i only get the welcome screen with the scart lead conected but i just want to use the RF conections, i've tried tuning the TV but no picture and its not a reception problem because you get the welcome screen before you even start to tune in the digital channels, so is there a reason why i can't see anything with just the RF conected.

[Krispy Kritter]

I don't know which box you are specifically using, however, the couple that I looked up only list scart or s-video output.