Every TV signal is "analog" in the sense that its signal strength continuously varies with changes in atmospheric conditions, interference, multipath, etc. The difference between analog and digital signals is in how they are modulated, not in how they propogate. So two signals of essentially the same strength, approximately the same channel number (i.e., close in frequency) and coming from the same source, one digital and the other analog, should both be received by your antenna and distributed to your attached equipment about equally. The difference then is in how they are processed. A weak analog signal will be snowy or show other signs of interferrence whereas a weak digital signal will suffer from excessive bit error rate which is what causes the pixelations and dropouts. It's much more difficult to diagnose the signal path difficulties with a digital signal since you can't watch for improvement in the picture with changes in the antenna, etc. With digital it's all or nothing. Someone skilled in the art and with the equipment could attach a spectrum analyzer to your antenna to determine the strength of the primary signal and anything interferring with it, but that is beyond what most of us can muster. Sorry I don't have answers better than that.
That said, many if not most digital signals are being placed on the higher frequency channels (UHF) that require higher power for equal propagation distance as their VHF analog predecessors. Also, as others have said, UHF signals tend to be more directional than VHF, and also can't follow the earth's curvature so their effective range is proportionately lower.