Early reports indicate that SDV does not save as much bandwidth as hoped. To simplify things a bit, think about the demographics in your area -- there are probably high income neighborhoods and lower income neighborhoods (rich people don't build big houses in trailer parks). Thus, hoseholds with HDTV tend to be grouped togther in the same neighborhoods. Moreover, people with HDTVs tend to watch a heck of a lot more hdtv than sd analog. If only HDTV stations are put on sdv, chances are that the people in these high income neighborhoods are watching a good number of the HD channels at the same time. To get the bandwidth savings, the entire lineup needs to be placed on sdv. This means an all digital lineup. However, going all digital, in and of itself, makes room for 150-200 or so HD stations without the use of sdv. So, it really makes little sense to use sdv at this point without going all digital. Nevertheless, one particular company is going full steam ahead, while most others seem to be adopting a wait and see approach.