This may be far afield, but I have a
C Band dish that recieves analog interference every 4 -7 seconds. It recieves interference from an old radar station when it is use. I understand weather radar can do the same thing. The explanation I got was that the radar interferes with the IF freqency in the reciever. When I use the same dish and LNBs for my Free DVB, it will pixilate. I know that direct TV is only a KU band not C band, but maybe you have some interference problems, local radio station ect. I never got rid of it, but
grounding everything helped. For What Its worth, Bruce