I have a LG tv with freeview inbuilt. I'm using an outdoor UHF aerial.

My reception has been fine for the past year. Since about two weeks ago, began to have bad reception for Tv1, 2, 3, and Four. a lot of times no signal for those channels. 

Starting from this week, I have very good reception for those channels in the day time. But everyday after 6pm, the reception become bad and even no signal. what could be the reason for this? could the day light be a factor?

There are some trees around which we can't trim because it's neighbour's trees. and we are near the power line too. could these be the factors?

All other channels signals are very strong. Only problems for Tv1, 2, 3 and Four. how come?