What is considered Good DVB -T signal

[sundancer]

Providing you have a good SNR (signal to noise ratio) and a low BER reading (Bit Error Rate) you should get a good solid picture.

Boosting the power of a weak signal using a mast head amp can help but only if its a clean signal. If is a noisy signal with loads of interference all you're going to be doing is taking a weak crap signal and making it strong crap signal. The old polishing a turd analogy. It doesn't matter how much you polish a turd, its still a turd.

Also make sure the aerial is set at the right polarity, as you wouldn't believe the amount of jobs i've gone to where the issue has been that the aerial has been moved to see a different transmitter and it hasn't been rotated 90 degrees.

General rule of thumb is that most main transmitters are horizontal polarity and smaller lower powered repeaters are vertical.