Sorry read post and saw you used ferrite chokes already. The ground to the exhaust pipe of the roof may not be helping. Have you tried using at least 1 if not more 5/8" 8-10ft ground rods? Also the A99 is one antenna known for its tvi/RFI bleed over. Mine did it to my neighbors computer speakers and Stereo as well. The ferrite chokes cleared this issue up. But I had to use multiple ones on the computer speakers. Also may want to try adding a coax rf choke at feed point of the antenna. May help, may not. Last question if this hasn't been asked, which direction is the dish pointed in relation to your antenna? I know my local just had dish tv installed and the dish is pointed toward his antenna, he runs a big stick, pretty much same as the A99, and he gets some rf back into the tv now. The dish is mounted within 10ft of his mast and is pointed up in the direction his antenna is mounted. I will say this, after changing antennas from an A99 to a sirio tornado, I have since not had any issues with the neighbors, took my rf chokes off the stereo and no issues, the computer speakers still get a very, very slight hum at times they say, but nothing like before. They could here my conversations before. I also have since added 12 large ferrite chokes at the feed point of my antenna and also a matching 1:1 balun. All is well now. No issues with anyone!! Hope you get it resolved.