LED Lights and TV Interference
Several months ago I started replacing some of the incandescent and compact fluorescent lights (CFL) lights in my house with LED lights. The LED lights are still relatively expensive, but the price is starting to come down. In addition there are now some more choices in the color (soft white, cool white, daylight, warm white) of the LED lights. The LED lights do use less power and are supposed to have a longer lifetime. Note that when the CFL lights came out, they also claimed to have a longer lifetime than incandescent lights – however I have had several CFL lights fail. I also like that the LED lights come to full power instantly vs. the warm-up delay with the CFL lights. I purchased several different brands for testing and have been relatively satisfied. So all is good — sort of….
I live about half way between the New York City and Philadelphia TV transmitters, so with a high-gain TV antenna in my attic I am able to receive over the air high definition digital TV signals from both markets. Some times when the seasons and temperatures change I have to tweak the alignment of the antenna and re-tighten the antenna cable connections. I was really looking forward to the season premier of Downton Abby, but the signal from WHYY in Philadelphia was getting scrambled. Trying to realign the antenna didn’t help. I did notice that the interference was only happening on stations that broadcast in the lower (what used to be VHF) frequencies. I about gave up, and figured that I would have to wait until the NJ PBS stations rebroadcast Downton Abby two weeks later. I turned the lights in my office off, and was going to go bed and read a book. Normally, I turn the TV off first (before the room lights) but didn’t this time. As soon as I turned the lights off the reception for WHYY was crystal clear. Turn the lights back on, and the interference reappears. What is going on????
I did a search on Google, and found several references to LED lights causing radio and TV interference. Apparently, some of the cheaper LED lights do not have sufficient shielding for the electronics converting the AC voltage to DC needed to power the LEDs. Bottom line, make sure that the LED lights you purchase are rated for low radio frequency interference. Some do have FCC markings, this one didn’t have any identifying information. I wonder if it is even UL tested/approved???? None of the other LED lights that I have been testing cause radio or TV interference.