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Your view: do LED light bulbs interfere with radios?

Multi-coloured leds

When we looked into the unusual issue of LED light bulbs interfering with DAB radios, we found that the stories were true. So we asked you to share your experiences so we could see how many of you were affected.

We sent a number of cheap, 12V LED bulbs to our lab for testing. And we found that when a digital radio was placed within a few metres of the switched-on bulbs, the signal went fuzzy. Within a few centimetres, the signal cut out altogether.

We asked you if you’d had similar experiences, and 2Dears was one of many who told us they had:

‘In November, we replaced 9 lights in the kitchen with 4.3w MR16 warm white LEDs for use “with an existing Lv transformer”. The DAB radio in the adjoining dining room stopped working immediately the lights were turned on’

We also heard from commenters like George who were having trouble with their FM radios:

‘Our FM kitchen radio gets a hiss over the speech (to the extent that BBC R4, our usual channel, is almost unusable) when the LED spots are on.’

John Dalton has a similar issue:

‘I tried to be green and bought some 12v MR11 LED spots for our kitchen downlighters. Switched them on and Radio 4 went to white noise on the portable VHF FM radio on the kitchen table.’

Shining a light on the problem

David Lewis had a big problem with LED bulbs, but he managed to find a solution:

‘I purchased Ikea lights (6 x 12v halogen bulbs) per 8m run of wires, plus transformer. With the lights on there was no interference of radio reception. I replaced the halogens with 5watt LEDs and replaced the transformer with the appropriate driver.

‘From then on – disaster. Switch one set of lights on and the station would be interrupted by a series of loud plops. Switch two sets of lights on and the tuner would cut out completely. Today, I replaced the indoor aerial with an external five element Triax DAB aerial. Problem solved. Superb reception with any number of LEDs on.’

A number of you experienced problems with electronics other than radios, like Keith:

‘I have two TCP 6W LED GU10 bulbs. The problem I have is when they are switched on and you stand near them, I have a high pitched whistle in my digital hearing aids.’

Tonyp isn’t too hopeful for a resolution, but we liked his metaphor so much, we’ve given him Comment of the Week!

‘There is little scope to make radio receivers less sensitive to this type of interference. The problem is that the lights are radiating energy at the frequency being received. Removing the interfering signal is rather like trying to remove the milk from a white coffee – possible but difficult and rather expensive.’

Looking on the bright side

But we’re pleased to report that a number of commenters, like Graham Pickworth, have had no problems:

‘I have six Aurora brand LED GU10 6watt 3000k non-dimmable light bulbs in my kitchen, purchased from Amazon. There is also a Bose VHF radio within 64 inches of the nearest bulb and I get no interference at all. I also have a Roberts DAB radio which I held up to within about 2 or 3 inches of one of the bulbs. Once again radio reception was perfectly clear.’

Finally, Wavechange had an interesting idea to help shoppers find the right bulbs:

‘LED lamps are expensive and the only way to be sure that interference will not be a problem is to test them in your own home. Perhaps ”bring a bulb” parties could be a new social event to help householders find out which LED lamps to buy.’

Comments

I just installed John Lewis Lynx LED strips under upper kitchen cabinets. Not a trace of interference with Pure DAB radio unless I held it within about 200mm (8″) of the controller.

gary says:
20 July 2013

i installed 6 led recess can and led drivers and now they interfere with the radio how do i fix problem

Neil Ackerley says:
20 July 2013

Gary,

Firstly have a look at http://www.ukqrm.org.uk/ and also the associated Yahoo Group. There are lots of ideas there and you can add your weight to the need to keep off the market LED systems which cause such havoc.

It is likely but not certain that the problem you have is caused by the drivers and not the lights themselves. Contact the supplier for alternative drivers.

Neil

Peter Wells says:
28 August 2013

We recently changed the 12 gu10 halogen lights in the kitchen for mains LEDs. The result is that our DAB radio is blocked on Radio 4. It still works on other stations! The lights are on two switched circuits. The radio is only blocked when the lights nearest the radio are switched on. When the further away lights are on Radio 4 works, but is slightly fuzzy, indicating a limited range to the interference.
It is possible that all led lights cause the interference, but when it is confined to a very narrow frequency band, it is only noticeable when trying to tune to specific stations.

Kuldeep says:
12 September 2013

I just had a Manrose shower fan fitted which has a built in LED light. All my DAB radios stop working when the light goes on.

I also had some Collingwood lighting Halers H2 Pro LED downlights fitted and these cause no interference at all.

Our own problem seems specific to the 12v MR16 LEDs (Crompton) in the bathroom which wipe out the bathroom Pure Classic DAB radio. In the kitchen though, another PURE radio is completely normal – untouched either by undercupboard LEDs (Howden kitchens) or ceiling fitted GU10s from Crompton.

We changed over to LEDs in the bathroom keeping the existing transformer for the halogens they replaced. What are the chances of improvement by replacing the transformer??

I have two wall lights in my living room and we used these with incandescent 60 watt reflector bulbs for reading as the 20 watt fluorescent ceiling lights were too dim and in the wrong place. I was not satisfied with the light distribution from the reflector bulbs and felt it might be worth the expense of fitting LED bulbs. I looked for the 10 watt Verbatim that was a Which best buy on Amazon and was directed to a 9.5 watt Verbatim that looked identical and was significantly cheaper. So I’m now very happy to have a much better even light to read by that is costing me less to run (and at an age of 79 should see me out). The brightness is much more like a 75 watt lamp than the 60 watts claimed.
I was so impressed that I bought 4 more identical lamps and two 6 watt LEDs to replace the spot lights in my kitchen. These are super and have reduced consumption from 320 watts to 50 watts. so I’m doing my bit for the environment.
I’ve just been reading about the electrical interference to DAB radios that some people are experiencing so I’ve tested these bulbs by holding my DAB radio aerial against the nearest lamp and am pleased to say that there is no deterioration in the sound quality from these Verbatim lamps.
However, on telling my son how pleased I am he warned me that the 30 year life expectancy may not apply when the lamp holder has no ventilation to let the small amount of heat generated by the electronics built into the lamp escape. One of his lamps (unknown make) had died in less than a year. I touched my lamps after being switched on for more than an hour and, while an incandescent 60 watt would probably have caused a serious burn if touched, the LED was uncomfortably warm considering its rating of only 9.5 watts.
I’d be interested to know if other users’ lamps have died from overheating.

I hope I am wrong but I think your son is right. Running certain components used in electronic circuitry at a high temperature can drastically decrease its life expectancy. Overheating of the LED chips is detrimental too, although that may just reduce life output – the reason is somewhere in one of the convos on lighting.

The most dramatic example of LED failure that I have seen was in lights set into the pavement in a city centre. Each lamp had about eight high intensity LEDs. Out of a dozen lamps, one was fully functional and another had just one of the LEDs flickering dimly. The others had one or two failed LEDs. My guess is that overheating of these enclosed lamps could be the reason for their premature failure.

I found the following on Voltimum’s website – just an extract:
“There are strict limits set on EMC for lighting products and most reputable suppliers test their products for compliance. The Lighting Industry Association (LIA) is aware of a number of reports of LEDs allegedly interfering with digital radio broadcasts and is in touch with both the BBC, which monitors this on behalf of the Government, and the EMCIA to establish just how bad the problem is.

………the LIA is conducting market surveillance on 2,000 LED retrofit lamps in its lab in Telford……”

I hadn’t come across EMCIA before – it is a UK Industry Association to look at EMC issues with its members – http://www.emcia.org. Delving into their site produced a link to what I thought was a very interesting document http://www.emcia.org/documents/members/LED%20Investigation.pdf. It shows what a mess there is, I think, and the disarray in taking resposibility for getting to grips with it.
Are Which? liaising with LIA and BBC on this problem? It seems to me that with the interest shown in LED interference this should be an active topic for Which? to follow up with other experts.

Neil Ackerley says:
7 January 2014

In May I reported that I had substantial problems from SAXBY LIGHTING LED downlighters. At the time I reported that OFCOM said that the lights conform to emc regulations. The lights were tested by accredited emc testing houses and the light systems proved to be 40 dB worse than the relevant emc regulation.(EN55015). OFCOM accepted that this is the case. 40 dB is 10,000 (ten thousand) times the permitted radiation. The problem proved to be the power supply which came with the lights. SAXBY sent a different set of power supplies also called drivers and the problem is resolved. The original drivers were labelled CE which implies they are conformant to the emc regulations but clearly they are not by a very large margin. It is hoped that Trading Standards and OFCOM are still pursuing this matter as they said they would and ensure that the drivers are removed from the market and recalled as necessary.

At least this article proves my point made in a previous post that got such a frosty response. At last the real experts are catching up, “scientifically proving the obvious”. Thanks.
Reposted: –
Surely it is not the LED lights that are the problem, it is the power units that drive them. All switched mode power units generate a whole load of EMI if not properly suppressed. …

Posted 14 May 2013 at 6:23 pm
0 – 1

Perhaps its not only RFI that may be a problem. An American site I subscribe to has been posting some interesting articles dealing with heat problems with LED’s. I imagine what applies in physics applies over here also though I am not a lighting guru. The comments of the respondees are worth reading also.

http://edn.com/electronics-blogs/led-insights/4423570/That-60W-equivalent-LED–What-you-don-t-know–and-what-no-one-will-tell-you-?

“Back to our story: Turns out that the consumer’s assumption is not valid: that the LED bulb is just another upgrade like the CFL. As noted, folks assumed that anywhere you had the 40W or 60W incandescent, you could screw in the CFL. This is not at all the case for a 40 or 60 watt-equivalent.
Within an LED bulb the internal generation and distribution of heat is such that it “desperately” needs access to cool surrounding air. The fact that it has that metallic housing is irrelevant in restricted air.
That 60 watt Wal-Mart bulb, when operating base down in open air and not even using a shade, has its internal LED case at 85°C, the absolute upper end of what is considered “safe” for full life expectancy. The same deal is true for competitive bulbs. Put a shade around it… and it’s a little warmer. Put it into any kind of base-up socket and it gets a lot hotter and all life expectancy numbers are off the table. Put it into any kind of porch or post light fixture, and it can fry, with its internal power supply components at the cliff edge of failure. Put the lamp in a ceiling-mounted fully enclosed fixture and set the timer for when failure will occur.”

If electronic components are overheated they will fail prematurely. Some CFLs come with a warning about using them in enclosed or semi-enclosed fixtures. I have seen three CFLs fail after little use in a single fixture and I have warned the owner that the same will happen again unless they switch to a fixture with ventilation. With LED lamps, there is the additional problem of overheating the semiconductor chip that generates the light as well as the control electronics.

We really have to get away from trying to produce a lot of light from something the same size as an incandescent bulbs, so that the electronic components remain cool and reliable. The issue will probably be forced by the difficulty of producing an LED equivalent of the humble 100 watt incandescent bulb.

Bernie Wright says:
20 January 2014

Regarding radio interference, one factor that does not seem to be being mentioned on this site is that with mains LED lighting, lamps with many LEDs (say 15 or more) invariably do not contain switching power supplies, so do not cause the sort of interference being discussed – but the 1-5 LED element lamps do, and they are the problematic ones, so if interference is a major concern, just go for the multi-LED lamps.

Big Col says:
26 January 2014

GU10 LED spots interfere with DAB radio and DVB-T/T2 television.
I bought 4 excellent LED spots (from eBay) as replacements for my Halogen vesions and subsequently discovered that they ruin reception completely. Just 1 on is enough to scramble the signal/output, while 4 remove it altogether.
These are the ones with 4 clusters of LEDs inside the lens which provide the light, NOT the chessboard effect ones. The have tiny little transformers inside the body, which are the source of the interference.
I cut strips from a thrown away aluminium can and placed them around the transformers. This did improve matters but only slightly. So I conclude – as have others – that the interference is transmitted back to the mains supply; thus allowing for the whole electrical wiring circuit to transmit interference.
So I will have to wait for someone to come up with individual transformers that work properly…

Tim Mackenzie says:
3 March 2014

Cheap mains-voltage powered LED bulbs may cause more interference compared to properly designed ones, but where a low voltage system is installed, the transformers can be the weak link from an interference perspective. Most modern transformers for low voltage lighting are of the “switch mode” power converter type whereby the mains power is rectified to DC, then “chopped” through an inductive winding to give the converted power output. The chopping frequency is normally around 40kHz with a pulse width varying at the required output frequency (50 / 60 Hz). The result of this modulated chopping is a series of radiated harmonics every 40kHz (40, 80, 120 etc). What this amounts to, is that the power converter is potentially a very effective RF noise generator. A badly (or cheaply) designed power converter will completely obliterate the AM band (500 to 1700kHz) even when operated within its specification. The electrical noise from the power converters is worsened by using LED bulbs on an improperly designed unit because the chopping circuit is forced to use too narrow a pulse width to maintain the output waveform. Having analysed the output from a number of popular power converters, it is clear to me that they are probably the greater source of RFI in such lighting solutions. However the interaction of the non-linearity of LED lights and their considerably smaller power usage, (which causes the power converter to be operated outside of its rated specification), exacerbates the problem of an already electrically noisy device.

{cross posted from /led-bulb-radio-interference-dab-test}

Justin Needham says:
24 July 2014

I also believe this to be the case. I spent many years in electronics industry working on mobile radio phone circuitry, and have correspondingly spent a lot of time in radio anechoic chambers, measuring and subsequently needing to deal with EMC emissions.

Nowadays I have traded down and am a practicing Electrician, expounding the virtues of good quality LED lighting.

I would say that on balance the respondents here have more issues with those LED’s which rely on A.N Other 12V transformer (of uncontrolled performance, often old stock intended for Halogens). So your comment Tim makes sense.

Those industries which test LED bulbs for emissions will, for a GU10 have a complete “system” within which the manufacturers (for any reputable CE marked brand) will have had to adhere to limits. (Now whether these limits are satisfactory to prevent interference to DAB is a moot point, but the main issue is that the system is at least “contained”, and to the extent that these things are, repeatable, and under control).

Those lamps reliant on an external transformer of unknown origin are only half a “system”. The manufacturers and test houses may well test those 12V lamps and they may well pass, but they will be tested doubtless when driven by a well regulated and well suppressed, probably well screened laboratory 12V power source. The idea would be that any emissions seen and measured would ONLY be off the lamp.

When the lamp is combined with an uncontrolled source, it’s the combination, as pointed out by Tim, which emits RFI and frequently the transformer (which has a number of physically large emitting elements, many of which could be convenient fractions of the relevant wavelengths to radiate nicely, and probably poorly designed for EMC with cheapo single-layer boards, poor layout, no earth planes etc…which would emit much of the noise from the system.

So indeed, it is quite likely that many of the bulbs that readers here have problems with might themselves PASS the relevant emissions specs. (probably many wouldn’t also..). But the point is made that generally speaking we should be safer with GU10 230V parts, not because they are 230V, (because all LED’s are driven by switch mode supplies), but because the bulb and it’s build-in power converter is one controlled element which can be tested and sold as clean.

I have had a customer recently where I made a swap in a price-sensitive application of under cabinet lamps for 12V LED’s where the drivers were uncontrolled and outside the “system”. The light quality is very good, but DAB radio interference is the result. Now I need to see how bad it is and will be scratching my head about whether I can add any suppression. This is all unpaid time for me. Lesson learnt for me is not to recommend such 12V lamps. – This may mean loosing customers who can’t afford integrated 230V solutions.

Alan says:
26 May 2014

A pub has re opened near me, 150 yards away.
After refurbishment it has been covered with LED lamps, front and inside.

When they switch the things on, which is lunchtime and then in the evening, my DAB goes haywire.
Also the radio in my car is interfered with as I drive past, this is how I guessed where the problem was.

I took a little portable radio with me and walked past ( when I saw it was LED) even yards away I cannot hear staions on my radio just a buzz.
No Radio 4 on longwave, no Radio 5, FM or DAB

How can this rubbishe be on the market.
If mobile phones are a health hazard then surley these must be too!!!

They should be banned.

Has anyone had any interference inside the house from external LED lighting please?

I’ve just noticed the post by Alan on 26 May 2014 that appears to answer my question. Thank you Alan.

We installed 9 down lighters in our kitchen using low voltage GU bulbs and transformer etc fitted by a qualified sparks and when we switched on the DAB radio, the signal, normally 95 to 100% dropped to 7 or 8% according to the radio’s own screen and transmission was lost We tried another battery- only set and this was the same,

Is there a filter available anywhere to counter this effect

OL

Sandra says:
9 October 2014

I recently bought led bulbs to replace the ones in my 6 kitchen downlights( trying to save energy and cost plus to create a better light) …firstly bought the ice white ones, put them in, very bright, but thought would get used to it. Then tried radio (not dab) got real bad interference when lights on. Same when plugged radio into other sockets in the room and even in the next room and also in an outside plug near the kitchen door. I then decided to buy replacement led bulbs in a warm white, hoping radio might work, no such luck. Now I am deciding whether to preservere with the lights but no radio or to revert to non led, at more expense!

Any suggestions please?

Justin Needham says:
9 October 2014

Sandra. From what you say, I’m guessing that you previously had 12V Halogen (The type with two smooth thin pins) MR16 style.

These are a case in point and the subject of many posts above. It’s not necessaily the bulbs to blame but the drivers (which you had already).

Bottom line is you’d need to replace the fittings with 230V type, either GU10 type with new “cans” in the ceiling, or ideally integrated ones in which the bulbs cannot be changed. Electrician required I am afraid. I could give you a quote but I;m unlikely to be close to you:)

And look out for 2700K “extra warm” white if you liked the old halogens.

Rgds

Sandra says:
9 October 2014

Thank you for this information. I am a widow, and not really clued up on electrical issues! I did wonder if it was going to mean replacing the fittings. Thought it was a good idea to try and save money, seems it’s going to cost me ….speculate to accumulate I guess! I am sure I can find a sparky nearby, but maybe I will need to sit down before I get a shock! Lol!

Sandra says:
9 October 2014

Thank you for this information. I am a widow, and not really clued up on electrical issues! I did wonder if it was going to mean replacing the fittings. Thought it was a good idea to try and save money, seems it’s going to cost me ….speculate to accumulate I guess! I am sure I can find a sparky nearby, but maybe I will need to sit down before I get a shock! Lol!

My son has just rung, he said they are GU10!

Justin Needham says:
9 October 2014

Hi Sandra,

Well in that case it proves we are all learning with these. – A quality mainstream manufacturer (as opposed to cheapo Ebay specials) would have “CE” marked these sort of GU10 bulbs and thus testing would have taken place in a calibrated anechoic chamber for radio emissions.

– Now that’s not to say having done so they would not interfere with your radio at all, (they will always emit something), but it would mean they met an industry standard level of radio emissions which at least does have a level of sorts..

So I’m wrong on that one. I’d be interested to know the brand of the GU10 bulbs you are having trouble with.

Rgds

Steve, g0xak says:
10 October 2014

My neighbour has installed led down lighters in their kitchen, the equipment is made in china. Now at night I have S9 of noise right through the HF bands up into VHF. This has practically ruined my hobby as I am unable to use my radio equipment at night when their lighting is on. They have acknowledged my problem, together we are trying to find an alternative led lighting solution.

Teknosquidgy says:
27 October 2014

Hi all, well been scratching my head for a couple of days now and this thread has verified my initial suspicions, this time in a car! I have a DAB radio installed in my vehicle and it’s been fine. About a week ago I fitted daytime running lights (LED’s and made in China) They are brilliant and do the job 100% but as soon as they are on the DAB signal is gone! Put them off and we have DAB signal again. I found this very odd with car radio specialists telling me they have never heard of an issue like this…well, seems I now know the answer! I am going to try some additional suppression across the powered antenna as well as across the LED unit wiring and see if I can improve it at all. A very interesting case and a problem highlighted! Thanks to everyone’s contributions!

Mike Thomas says:
24 November 2014

A very simple fix is to insert ferrite cores in the low voltage feed to the :LEDs

Justin Needham says:
24 November 2014

But..

A) Something of a variable quantity, being that there’s a vast array of possible ferrite types, permeability, size etc. Ferrite beads at the best of times are more of an art than a science.

B) Most people affected won’t even know what a “ferrite core” is, and it’s unlikely they’s have the ability to get one onto the low voltage feed.

C) Probably no space to fit one anyhow. Take under cabinet G4 puck lamps for example, nice little LED alternatives, no chance of fitting a bead anywhere!

C) And that also assumes the noise is coming off the lamp, and it may well (more likely IMO) be off the driver.

I would not discount the suggestion of using some form of ferrite on the lead, as Mike has suggested. The lead could be acting as an aerial, transmitting the interfering signal. The ferrite need not be in the lampholder.

In the previous Conversation one or two people had no success with ferrites. Perhaps using screened cables between the lamps and power supply would help, though that would require a little more expertise.

neil ackerley says:
24 November 2014

All this talk of ferrites misses the point. The biggest culprit is the led drivers converting mains to a low voltagr. It is quite possible to design and manufacture them so that they don’t cause interfence. However what comes onto the market are drivers which don’t conform to the emc directives and in some cases certain components have been left out of the drivers. The original designs were probably fine but not the production models.

You could consider reporting your problem, Neil: http://consumers.ofcom.org.uk/tell-us/tv-and-radio/tv-or-radio-interference-or-reception-problems/

When I was a young man I was living in a semi-detached house with an old couple next door. I explained that their TV was causing interference with my FM radio, but all I got was helpful comments such as their TV was working fine. My problem was confirmed and my neighbours got a visit. It turned out that their TV was rented and the company gave them a new TV, so there was no unpleasant incident.

Obviously we need to get non-compliant drivers and lamps off the market and reporting serious examples to Ofcom should raise awareness of the problem. I don’t see a quick way of getting substandard junk off the market.

A reputable manufacturer points out that despite testing for compliance with EMC standards (e.g. CISPR15) the installation will be different from standard test conditions and EMI can result, coupled through the wiring or radiated from lamps/ luminaires for example. Their recommendations are to use a transformer/driver with good EMI suppression (so a reputable make), minimise cable lengths, use shielded cable (Belden), and add EMI filter/choke at input/output of transformer – e.g. EMC ferrites.

I agree with Malcolm about the exact nature of an installation being important when considering interference. There are various good practices in helping to avoid creating interference.

I believe that it is reasonable to expect an owner to use the recommended driver and ensuring that installation is according to the manual before filing a complaint, especially since both lamps and drivers can be a source of interference.

wc “I believe that it is reasonable to expect an owner to use the recommended driver and ensuring that installation is according to the manual before filing a complaint, especially since both lamps and drivers can be a source of interference.”

I would agree but for the fact that they are being sold without the information that isnecessary to the public. Anotherwords the supply chain and media and government are all extolling the virtues with out highlighting that there are pitfalls. Which? itself is guilty of not mentioning radio interference as downside.

In my case it was even worse. The instruction leaflet which came with the lights indicated that the drivers were constant current but also indicated that 1 2 3 or 4 clusters of LEDs could be attached to each driver. The set up by the electrician (who possibly didn’t understand what constant current means) wired them with two sets of LEDs on one driver and four on another. Close inspection of the specification of the LEDs and drivers showed that the correct current would be supplied only when 3 clusters of LEDs were attached to a driver. You can see that the set of four LEDs would be under-driven and therefore dim whereas the set of two LED clusters would be considerably over-driven therefore being bright but more significantly would have a much reduced lifetime.

It gets worse. The emc testing house tried only one LED cluster on a driver (the instructions indicated that this was allowable). What they found was that the LEDs were very bright and pulsed in such a way could trigger an epileptic fit for those prone to such.

The replacement drivers were constant voltage devices which might seem to solve the problem but bear in mind that these LED clusters are intended for kitchen down-lighting and therefore are likely to be above heat sources. The effect of that is that the LEDs typically take more current if they are heated. Guess what? With constant voltage drivers they will draw more current thus reducing their life.

So the real answer is to have the correct number of LED clusters on emc conformant constant current drivers.

An LED chip is a constant current device, so a decent constant current driver should operate the LEDs at their correct current and appropriate light output up to the driver’s maximum connected load. Light output is dependent upon the current through the LED. You probably had rubbish drivers?