 Digital signals do not have 'grade b' signal areas, and are either 'in perfectly' or 'not in at all'.Further, since most stations have elected to use UHF rather than older VHF channel allocations, their actual broadcast range is far less than previously.Viewers in major metropolitan areas will likely not notice problems; however, rural TV users have generally had most and in some events all of the stations they previously received with acceptable but not 'perfect' signals fall over the digital cliff (as the loss of signal has been described).