I'm a lighting manufacturer and have started to hear complaints about outdoor LED lights interfering with garage door openers (GDO's). It's a known problem that many electronic circuits can interfere with these RF transmitters/receivers. After talking with Chamberland, a major mfg. of GDO's, they tell me that RFI can come from other RF devices that transmit at certain frequencies; and it can come from devices that somehow transfer interference over electrical wiring. GDO's typically transmit at 315 MHz. LED engineers tell me that a properly designed LED circuit will limit or filter unintended RFI. They also say that they wouldn't be surprised if many of the cheap China exports fail to control RFI. A few questions: 1. Would it be possible that a 12V AC LED circuit could somehow transfer interfering frequencies through it's lead wire, through a torroidal transformer, through the house wiring to the garage door receiver? 2. If that's possible, what could an electrician put in place to block this transmission? 3. Regarding the interfering frequencies, Chamberland tells me that other devices that transmit at the same frequency (315 MHz) can definitely interfere, but other frequencies may also interfere. Can someone explain how this is possible? 4. I understand that RF emissions can be measured with certain equipment. Does the same equipment also measure the sort of frequencies that travel over wires? Are the two types of transmission (air and wires) basically the same? Thanks for your help.