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Thread: LED headlight desensing FM radio

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    Premium Member Kevaclone's Avatar
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    Default LED headlight desensing FM radio

    I have LED headlights fitted to 3 of my cars as well as LED spotlights on my lanmdcruiser
    The issue I am having is that they appear to desense the FM radios or overload them with out of band interference so I lose signal. and high beam is worse. The Landcruiser with the spots is the worst of all with no radio signal at all

    Not sure how to fix this. Fit a filter to the antenna cable? and what type?
    Or I have seen some people say a ferrite ring to the power cable for the lights but no one actually saying that this works

    Anyone have any ideas?
    Thanks
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    If you find a solution Id like to know My Getz has LED headlights and does the same thing .I have yet to find a fix. As for the ferrite in the + line I tried that and no luck .my next trick is going to try a capacitor (suppressor) on the + and other to - ground and see if that filters the interference . Just trying to work out a good value .

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    Are we talking about broadcast reception, or comms radios?

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    Unfortunately it's likely the quality of the LEDs.

    I used to run Chinese aftermarket LEDs on my truck that were from EBay. Noisiest darn things I've ever used. My comms radios would have 9db added to the noise floor and my broadcast radio would pick up noticeable static.

    I recently got some new LEDs with Cree diodes in them and they're better, but still somewhat noisy. About half as noisy and about twice as bright. Two 2x2 lights I got from Rural King.

    I got some really nice LEDs for my motorcycle. Rigid Industries 20211s. They're super bright and super quiet.

    From what I've seen with this progression, it leads me to believe that it's the quality of the light that makes the difference. You could try putting some ferrites on your feedline but I doubt they will block that much interference.

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    It may be the buck boost, constant current, driver radiating too much EMI, so shielding that is the only way to decrease it. The same thing happens with caravan internal lighting stuffing up your TV reception, unless you use 12V only lights.

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    Does this problem still exist with the engine not running?
    I stand unequivicably behind everything I say , I just dont ever remember saying it !!

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    Quote Originally Posted by gordon_s1942 View Post
    Does this problem still exist with the engine not running?
    Yes. It's not engine related.
    If you can't run with the DOGS, Stay on the Porch

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    Quote Originally Posted by bob_m_54 View Post
    It may be the buck boost, constant current, driver radiating too much EMI, so shielding that is the only way to decrease it. The same thing happens with caravan internal lighting stuffing up your TV reception, unless you use 12V only lights.
    Yeah ok. Not much can be done with the all in one types then. My Subaru has separate driver boxes inline so I may be able to wrap those.
    If you can't run with the DOGS, Stay on the Porch

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    Quote Originally Posted by mtv View Post
    Are we talking about broadcast reception, or comms radios?
    Haven't had an answer to my question, but I agree, it's often noise generated from the drivers.

    Ferrite toroids with as many turns of power cable, or clamp-on type if you can't make windings, both on the power cables at the lamps and as close to the radio as possible, may help.

    The same with antenna cables.

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    Quote Originally Posted by mtv View Post
    Haven't had an answer to my question, but I agree, it's often noise generated from the drivers.

    Ferrite toroids with as many turns of power cable, or clamp-on type if you can't make windings, both on the power cables at the lamps and as close to the radio as possible, may help.

    The same with antenna cables.
    Sorry Mines with Normal FM Radio stations ,

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    Shades of the early days of CB radio (27Mhz) and interference on AM from the Car's electrical system.
    After market AM car radios also suffered from this interference from the Coil, Distributor and Generator.
    Later when Alternators replaced the Generator, they too could be 'noisy'.
    I remember adding suppressors on the Spark leads, capacitors on the Distributor and Coil and running a separate power supply from the Battery to the radio and hanging whatever filtering was available on it too.
    Some of the 'noise' was in the leads which seemed to be easier to reduce or eliminate but if was 'Broadcast', a major problem for the average user to deal with.

    If there is some sort of circuitry used on these lights, could it be 'shielded' by wrapping foil around it and 'earthing ' to the Car's body? Thats if theres any metal there.
    You may need to ensure adequate ventilation gets around the circuits or it might blow it.
    Last edited by gordon_s1942; 28-03-18 at 01:00 PM.
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    Quote Originally Posted by gordon_s1942 View Post
    Shades of the early days of CB radio (27Mhz) and interference on AM from the Car's electrical system.
    After market AM car radios also suffered from this interference from the Coil, Distributor and Generator.
    Later when Alternators replaced the Generator, they too could be 'noisy'.
    I remember adding suppressors on the Spark leads, capacitors on the Distributor and Coil and running a separate power supply from the Battery to the radio and hanging whatever filtering was available on it too.
    Some of the 'noise' was in the leads which seemed to be easier to reduce or eliminate but if was 'Broadcast', a major problem for the average user to deal with.

    If there is some sort of circuitry used on these lights, could it be 'shielded' by wrapping foil around it and 'earthing ' to the Car's body? Thats if theres any metal there.
    You may need to ensure adequate ventilation gets around the circuits or it might blow it.
    Shielding most of my lights would be impossible because they have large heatsinks with fans for cooling. Some do have separate driver box(one set I have) which could be shielded
    If you can't run with the DOGS, Stay on the Porch

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