Frames missing

I previously had a Sony DTV receiver and everything seemed great. I
recently (upgraded) to the locals package which required I change my
dish and receiver. DTV offered the free dish and receiver for
upgrading. I had it installed (Phililps) and it now seems as though
some channels are missing video frames. The pictures seems to have a
jerky motion. Not pixelization but a faint jerky motion which I did
not have with my previous receiver. Is this from compression or is it
the new receiver causing this? Any ideas greatly appreciated!