LED Lights Interferes with DAB signal

Discussion in 'Music Streamers' started by anthonylawrence, Sep 26, 2010.

  1. anthonylawrence

    anthonylawrence
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    I have a DAB radio that works well but as soon as I turn on my kitchen lights, there is no sound. It comes back as soon as I turn the lights back on. I have 12 LED 12 ceiling lights powered by 6 transformers. Originally I had 12 50w halogen lights but changed these to LEDs to save on power costs. I did not change the transformers. I suspect that it is the transformers causing signal interruption. Are there transformers out there that dont have this effect on DABs? I have an external digital aerial and signal amplifier (which does not appear to make any difference). Any assistance from clever guys that know how to solve this would be most appreciated.
     
  2. Chris Muriel

    Chris Muriel
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    You need to try some detective work to ascertain whether the inteference is being radiated (transmitted through the air) or conducted through the mains.
    Is it possible to run the DAB radio off batteries ? (eliminates the mains).
    If mains borne, it may be possible to filter it: surge protector with sufficient RF filtering or mains conditioner - like Belkin one on which there is a thread in the Home Cinema Bargains section or Tacima (mentioned in Interconnects and Cables section from time to time).
     
  3. PennyWalker

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    Did you find a way to solve this problem?

    We are in the process of having a new kitchen fitted, with LED lights, and we have found exactly this problem!

    Thanks

    Penny
     
  4. Chris Muriel

    Chris Muriel
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    The original poster only ever made that single post:(
    I hate it when that happens - folks should tell us if and how fixed (or not).
    I would love to play with my spectrum analyser, along with some surge protectors,. ferrites and some makeshift screening (cooking foil) in this sort of set up to see what's happening .
     
  5. PennyWalker

    PennyWalker
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    Hi Chris,

    I don't have your level of curiosity or persistence (mea culpa), I just want to be able to listen to the radio with the lights on!

    So it seems this is a problem without a simple solution as yet?

    Penny
     
  6. Grumpsimus

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    Unfortunately, this is not a simple problem, so there is no single simple solution.

    The radio is picking interference from the LED lights/transformers and the interference could be via the mains or the air. There are lots of different models of LEDs and transformers, which are likely to have different levels of interference and new models are appearing all the time.

    I suspect the problem is likely to be worse in kitchens, because there are more lights/transformers and the radio is often nearer too them.

    Solving this, like all interference problems, involves a lot of patient detective work, it is almost never easy.

    Any obvious solutions are likely to expensive an probably unacceptable. You could replace the LED lights or pipe in the radio from another room i.e. Sonus (good but expensive).
     
  7. PennyWalker

    PennyWalker
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    Thanks very much for this explanation, Grumpsimus.

    As LEDs and digital radio are both likely to become much more common in the UK, for different reasons, I guess a lot of people will come across the same problem.

    For now, we are just not turning on the bigger ceiling LEDs. The smaller ones under the cabinets don't cause the same problem. Not sure how well this will suit us as the days get shorter...

    Cheers

    Penny
     
  8. Grumpsimus

    Grumpsimus
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    You certainly right in thinking the problem is getting worse. At present few people use LED lighting on a large scale, mainly because high power LEDs are still quite expensive.

    One area where the problem has been seen is small boats, which often have a low voltage electrical system and run off batteries when the engine isn't running. LEDs are good for lighting as they offer a much lower load on the batteries. However, because the cabins are very compact the LEDs often interfere with the radio equipment, the only solution is to turn the lights off.

    The problem is probably getting worse for another reason. In order to prolong the life of the LED, they need to be run off a constant current source, which is provided by a switched mode electronic power supply. The frequencies used in these power supplies is getting higher, producing interference in the range 30 - 300Mhz. DAB in the UK is roughly in the 210-230 Mhz band. Easy to see why the problem happens.

    These circuits should of course be suppressed, but the quality and effectiveness of the suppression is very variable. Some LEDs are much better than others and some people have no problems using radios etc near to them. Unfortunately, I am not aware of any easy way to tell which are the better LEDs, other than to test them and find the ones that do not cause problems. This is rather an expensive option!
     
  9. supraTTman

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    Pennywalker - I'm curious to know what type of LED's you are using? Are they MR16 fitting? What is the make of the LED? Also, what transformers are you using if any? I have 8 off 61-LED SES (E14) lamps quite close to my DAB and have not noticed any oddities.
     
  10. antonyob

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    Ive also had this problem. Is a surge protector likely to make a difference. i thought they were just for protecting electronic equipment from power surges?
     
  11. Grumpsimus

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    It is highly unlikely that a surge protector would make any difference. You are dealing with RF frequencies which could transmitted via the mains or through the air to the aerial. If the interference is transmitted only via the main, a properly designed mains filter would help.
     
  12. Rodders53

    Rodders53
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    An important factor is the aerial. Although DAB will often work with an internal / room aerial one outside will always out-perform it. If the DAB radio signal is strong (close to a transmitter) the interference may not be an issue even with a room aerial.

    In a room with sources of interference (fluorescent lights, led lights with transformers) it can be conducted via the mains wiring {but the devices should have suppression built in and may be faulty}. If the radio will work on batteries and doesn't suffer then it is mains borne and the interfering devices need suppression adding.

    Moving the radio aerial away from the interference source can help if it is 'radiated' interference.

    Surge protectors don't usually incorporate much in the way of RF filtering circuits; if you have one it won't harm trying it but don't buy one especially.
     
  13. antonyob

    antonyob
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    that could be the solution rodders. i got this reply from my kitchen company who installed the lights, it may fix it, ill post if it does:

    I have spoken to the lighting company and they are going to send replacement drivers for the lights. There are 2, one for each set of 3 lights. Once they have been changed (you will need your electrician to do this) please send the old ones back to me at the showroom. The lighting company have had one other instance of this and it was due to a faulty part in the driver, an 8 watt, not a 15 watt like yours. They need to test your faulty ones to see what is wrong with them as it may be a batch issue.

    I am hoping this will solve your problem with the digital radio.

    Mod Edit: font tags removed
     
    Last edited by a moderator: Sep 6, 2011
  14. antonyob

    antonyob
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    ive had the transformers changed and to no great suprise from me they havent made an ounce of differnce.

    there is no solution as far as i can see and the kitchen company are basically saying its tough.

    not great, hopefully someone like Belkin can come up with something that helps otherwise its a costy external aerial which seeems like the proverbial sledgehammer to crack a nut!
     
  15. supraTTman

    supraTTman
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    This is a challenge as I have a fair amount of rf (radio frequency) experience.

    You haven't said what lights you have, how many you have fitted or how many transformers there are.

    You have eliminated the transformers - so the only other source of interference is the LED lamps - I assume these are 12V MR16's.

    You need to verify this by experimentation.

    Experiment No.1

    Remove ALL LED lights and fit just ONE really low wattage halogen lamp that is within the limits of the transformer feeding it. Does this fix it?
    Let me know the outcome then we can 'nudge' forwards.
     
  16. Grumpsimus

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    I do not think that the transformers have been eliminated as a cause of the interference, only that changing the transformers has made no difference. Both sets of transformers could and probably are causing the RF interference.

    It is highly unikely that the LED lamps are causing interference as these are low voltage DC devices.

    An interesting experiment would be for the OP to see how far he has to move the radio from the kitchen before it stops. It will give a very rough indication of the level of the interference.
     
  17. supraTTman

    supraTTman
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    OK fair point, but Experiment No.1 will verify this - or otherwise.
     
  18. antonyob

    antonyob
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    apologies for the late reply, ive been away. im still waiting for a replacement led fromt he kitchen company and that should tell me the model and make but apparantly it is one that their is no bulb at all so if it goes you have to replace the whole thing! more details to follow....

    If you do solve this you will will be the first person inthe entire world to do so!!
     
  19. supraTTman

    supraTTman
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    Did you try the halogen lamp - Experiment No.1?
     
  20. robwil684

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    Hello all, I have very recently replaced my kitchen halogen downlighters for LED ones to use less power. before i replaced them, our DAB radio worked fine in the kitchen. Now, when the lights are on it cant find a signal at all. As soon as i turn the lights on, the signal goes. It also happens if i turn the lights on in our en suite bathroom on the second floor! radio is in the kitcen so this is nowhere near to the bathroom at the top of the house. I would say that this rules out the transformers and the proximity issue. So, i am thinking it must be some RF interference through the mains when the lights are on. I will try batteries to determine if it is or not and re post later.
     
  21. supraTTman

    supraTTman
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    I assume you have bought 12V MR16's for the kitchen. What make are they?
    Are the en-suite lights the same make?
    If the interference is carried through the mains wiring then you could try clamp-on ferrites as close tothe transformers as possible.
     
  22. robwil684

    robwil684
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    The lights are MR16 halogen replacements and yes they are the same in the bathroom too. i dont know the actual make but they were purchased from a website called wholesale led lights .co.uk. what are clamp on ferrites?
     
  23. supraTTman

    supraTTman
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    OK this narrows things down a bit. Are you using the same transformers for the LED lights as you had originally powering the hooligan - sorry - halogen lights?

    With this 'new-wave' of energy-efficient lighting, there are only 2 sources of rf interference upsetting your DAB reception. Either the LED lamps are generating rf interference, or the transformers are. You need to use the process of elimination to home in on the problem. Like using batteries as you quite correctly suggested.

    At the end of the day, whether it's the LED bulbs or the transformers causing the problems, it is almost certain that these devices are 'using' the cables attached to radiate the interference - i.e. the wires are acting as aerials.

    Clamp-on ferrites, positioned close to the source of the emissions can supppress the amount of trash that is radiated by the cables. Maplin do a good range of clamp-on/clip-on ferrites. HEM3018 seems to be your best bet as DAB is at 220 MHz - check this link
     
    Last edited: Nov 6, 2011
  24. robwil684

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    Thanks for the quick reply. All we did was replace the actual bulbs so have the same transformers as before. There's no place for batteries in the radio as its mains powered only so we cant check that. I will look at maplins as you suggested. It's amazing that companies can sell these things knowing full well they will cause these problems.:mad:
     
  25. supraTTman

    supraTTman
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    If you are using 'old-tech' transformers these may not be suitable for your nice eco-friendldy LED lights and you may see some early failures of the LED's. I've 'knackered' a few MR16's using the the old white box transformers. Buy a switched mode power supply that can handle any load.
     
    Last edited: Nov 6, 2011
  26. formbypc

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    OP, or others affected; which radio stations do you listen to?

    If these stations are still on FM, why not try an FM radio in the same place?
     
  27. larkone

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    I did some research on this and came across a lot of boat people complaining that after they had fitted LED lights in their boats they had problems with their comms radios. It would seem that it is the cheaper Chinese made LEDs that cause the biggest issue. It is because of the use of cheap switching power supplies that don't suppress EMI properly.

    Interesting article here
    Radio interference from LED lighting | EMC and Regulatory Compliance
     
  28. supraTTman

    supraTTman
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    This is quite surprising. I've completely re-fitted out my boat with 20 odd MR16's from Lustrumlight of various flavours (21/60 LED warm white, cool white) and seen no problems with rf interference with marine VHF/FM/DAB and have no doubt that these are of Far Eastern origin.

    I can understand 240V GU10 LED's interfering because LED's need 2.5V DC and so some serious drop in voltage/current is needed by way of an efficient convertor (electronic transformer). Boats are 12V DC and MR16 LED lamps simply wire 3 LED's in series with a 100-200 ohm resistor as with RGB LED flexible strips. Nothing here to generate rf 'trash'.

    In short, I can't see why MR16's are causing so many DAB reception problems in homes other than the obvious reason - the 'transformers' are entirely responsible. Some process of elimination is needed to solve these recurring problems as I have suggested all along.
     
  29. larkone

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  30. Paul W

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    i also have just been through all these aledged fixes to which none of them worked, except the last one. i have 9 LED lights in the kitchen that ran on 3 electronic trannys perfectly but pee'd the radio and DTV off when they were switched on. only on one TV channel and all DAB stations were affected. it seems only the larger groups of lamps do this (6 or more ) to which i fitted one 12v 10A switchmode DC power supply and hey presto no more problems. in saying that the 6 in the main bedroom dont affect either the TV or radio.... go figure :smashin:
     

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