Actually, that problem is due to be resolved in the near future. The primary reason DTV has such a pathetic signal strength right now is the rule of levels the FCC follows. In other words, when switching spectrums, a transmitting station is given a license for the lowest allowable signal strength in that category. In the case of DTV, (or TV in general), the current strength is 20,000 watts.

Once it's proven that the newly assigned frequency does not create problems with the local wireless communications networks, most especially emergency channels, or other services and equipment in the area, then the station is allowed to raise it's power to the next tier, which is 50,000 watts. Once they complete the trail time at that power, they're allowed to go back up to 100,000 watts, assuming they already had that as their maximum power. If they had a higher output, which is unlikely, they'll stay at 100,000 until they pass testing at that tier, which of course then means the cycle repeats itself again.

It was said that most stations of 50,000 watts or higher would be allowed to move up to 50,000 watts very soon, so you should start seeing some of the harder to get stations suddenly become easier to get.