I bought a small flat digital free view tv' i cannot get all the stations on.?

I bought it for the kitchen, please dont ask me to connect it to the main aerial, or similar' [kitchen some distance away].i bought a booster it works' just about? but some of the stations are weak to pick up..please advise me. thank you.
Answer
Signal strength varies between the channels as an example the itv channels on my freeview tv have full signal all the time, bbc channels (the ones you pay for with your licence) sometimes 50% sometimes nothing, tmf etc vary between 25% & nothing-depending in what the weather is like-if its nice like the last few days then they work, if its raining then nothing, not as if i live in the sticks-live in birmingham