OK I have just added another split to the feed from our UHF aerial and I am now getting more pixilation on DVB-T recording. I was getting it occasionally before mainly when recording more then one thing. However now it is quite a bit worse. The single feed is split into 4. 2 to HVR 3000 cards, 1 to HVR 2200 (which then splits it again internally). I have now added a further feed for the TV which has a DVB-T turner.

What is the correct way to increase the signal? Larger aerial on the roof or a amplifier?

Edit I am located in Wainui. Existing aerial is old and I think 20 elements if I am counting correctly?