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LED RF Interference

Discussion in 'Landscape Lighting' started by jshimmin, Nov 13, 2010.

  1. jshimmin

    jshimmin LawnSite Member
    Messages: 99

    I have knowledge now of two cases where MR-16 replacement LED's have rendered garage door openers inoperative.
    Both cases were installs that had halogen systems retrofit with drop in MR-16 replacements. One was cured by going back to a halogen in one particular fixture, the other was several.
    Different MR-16 LED's did not change the interference.

    Has anyone else seen this?
  2. steveparrott

    steveparrott LawnSite Bronze Member
    Messages: 1,276

    RF interference form LED's is a real issue. A google search brings up numerous references to LED interference of VHF radio frequencies in the marine industry. (Quite likely that garage door openners operate at similar frequencies.)

    This may also become an issue for some of the VHF-operated remote control units.

    Can anyone add to this knowledge?
  3. jshimmin

    jshimmin LawnSite Member
    Messages: 99

    Garage door openers run between 300-400 MHz depending on the age. Due to my back ground, I have a spectrum analyzer that I can actually look at the spectrum with. I can definitely see noise all over the spectrum when close to a fixture. Seems like some manufacturers are noisier than others.
  4. steveparrott

    steveparrott LawnSite Bronze Member
    Messages: 1,276

    An addendum to this issue.

    Today, I had another call from a homeowner. She believed that our transformer was interfering with her garage door opener. I asked if she had any LED lights in her system. She replied, "Yes, I have one mounted above my garage door."

    Prompted by the complaint, I talked with our LED engineers. They educated me further on the issue. Low voltage LED's, due to their circuitry that converts AC current to DC, are especially likely to emit a broad range of frequencies that generate electromagnetic interference (EMI).

    They went on to explain that responsible LED manufacturers are well aware of this likelihood and will use high-quality components and filtering to reduce the EMI. This is an area ruled by the FCC who require that unintended EMI be reduced enough to ensure no interference with devices likely to be affected.

    The engineers went on to assure me that our LED's would not emit this troublesome EMI. They were not surpised that some LED replacement lamps out of Asia lacked the quality components to prevent the problem.

    As designers and installers moving towards LED's, I suggest we be alert to this EMI issue and come to recognize which manufacturers utilize best practices in the design of their electronics.
  5. Classic Lighting

    Classic Lighting LawnSite Senior Member
    Messages: 512

    With such a broad spectrum of LED suppliers, how do we know who utilizes EMI filters?
  6. worx

    worx LawnSite Senior Member
    Messages: 252

    Maybe James has some insight on this. Perhaps they are working to resolve this issue.

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