digital DVB TV reception is not so good why and how can I fix it?

[Glinterceptor]

I get great reception on the old analog but miss out on the digital DVB some stations are perfect on this new format but I miss out on other stations why? The people next door are fine with there reception... but then again they have a newer aerial. I'm looking at getting up and adjusting the antenna as a cheap option by doing this I'm trying to eliminate the possible courses and saving money to start with. If this fails what next as far as eliminating possible courses?