Today I identified a small but vexing problem I’ve had with TV reception. My TV is a typical digital HD model, now several years old. I run three inputs into it:\n\nAn antenna cable, roughly 50-75 feet long, connects the TV to a UHF antenna in the attic. The cable is RG-6 with the usual F connectors. Guessing by its thickness, the cable is quad shielded RG-6Q, but I’m not certain about that.\n\n\nAn HDMI cable runs from the AVR to the TV. It delivers video from a Blu-Ray disc player.\n\n\nA Google Chromecast dongle also connects to an HDMI receptacle on the TV. It is fed DC power by a USB cable coming from an AC outlet. This dongle consists of a flat disc body dangling from a 4” long HDMI cable. The DC power line plugs directly into the dongle body. It's HDMI receptacle on the back of the TV is right next to several other HDMI receptacles, and the threaded post for the antenna cable.\n\nSoon after I added the Chromecast dongle, I started having minor occasional interference problems. I would see brief pixilation on the screen and hear rapid on\/off interruptions of the audio. This was usually short lived, and occurred only if I watch broadcast TV via the antenna. Sometimes it didn’t happen at all, and other times broadcast TV was unwatchable.\n\nAt first, I thought I had damaged the F connector on the antenna cable when I installed the dongle. I changed it several times, without eliminating the problem. So I knew that one day I would have to crawl into the attic and trouble shoot this problem. What could be wrong other than the antenna or the cable? Lots of procrastination followed. It always seemed too cold or too hot to go up to the attic. Other times, I was just too lazy. After all, it was only commercial TV – I don’t have cable TV – and I watch more and more video through streaming sources.\n\nToday, the summer heat was gone, and I decided it was time to pull-down the ladder and climb into that unfinished attic. I found an old rabbit ears-type antenna and planned to attach it to antenna cable in the attic. That way, I could see if the problem was in the antenna or the cable. But before doing that, I thought it might be smart to attach those old rabbit ears directly to the TV, just to see how well it worked. That dongle was in the way, so I took it out before attaching the rabbit ears. That eliminated the interference! I replaced the attic antenna cable, but left the dongle off. I watched TV for a good hour just to see if that intermittent problem returned – it didn’t!\n\nThat identifies the problem. It was EMI from the DC-powered dongle, which is close by the antenna connection. How can I fix it and still use the dongle? I’ve got two ideas.\n\nShield the F connector at the back of the TV with aluminum foil. Also, wrap the dongle in aluminum foil.\n\n\nGet a short HDMI extension cable, 1 to 3 feet long, and put it between the dongle and the TV. Tie the dongle down so it can't get close to the antenna cable. That way the dongle and it’s USB power cable is farther away from the F connector.\n\n\nDo all of the above.\n\nDoes anyone have other ideas how I might fix this? @TLS Guy or @BMXTRIX or any one?