got a new sony bravia model kdl40d3500 - having some problems, please help!?

Not too sure if the new sony bravia kdl40d3500 full hd tv i have just purchased has a fault or whether the problem comes from the fact that my feed is off a communal digital (freeview) aerial. the tv signal says the strength of this aerial signal is high but the picture is, well hard to describe, sometimes a bit blurry and inferior looking to my old trintron 28".is there any way to enhance the picture quality? also, cant find anywhere in the instructions how to choose the input feed - tv appears to be set at 1080p at all times.hdmi feed from my sony hdd dvd recorder hxd970 was actually better than direct aerial feed initially but now this picture breaks up and "stutters".have checked all leads/cables and retuned tv and hdd recorder.dont want to look a fool by calling out a sony engineer, incase it is just me!any help, really appreciated. thanks,alex
Answer
Try with the freeview aerial plugged directly into the tv. i bought a hdd freeview box and it was a mess to start with as the picture was breaking up on some channels from both sources. changing the supplied aerial patch lead improved things considerably. it might be that reception is bad today but, if it is not as good as before, i will buy an aerial amplifier with two outputs.