The energy-saving LED bulb that switched off the radio

by , Senior Home Researcher Energy & Home 17 March 2013
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We get sent some weird and wonderful tales of products going wrong, but one story piqued our interest so much that we just had to send it to the lab to test it out. Can you help us shed more light on the mystery?

An LED bulb lighting up the darkness

Last year we received this intriguing message:

‘I recently changed six halogen down-lighters to more energy efficient LED bulbs. Unfortunately when the lights were switched on, the DAB signal on my radio was wiped out!’

To try and figure out this conundrum, we sent a batch of cheap, generic 12V LED bulbs to our lab and found that when a digital radio was placed within a few metres of the switched-on bulbs the signal went fuzzy. When the radio was placed within a few centimetres of the LED bulbs, it cut out all together.

The plot thickens

LEDs are ultra energy efficient light bulbs that can last up to twenty years and have been hailed as the future of home lighting.

It seems our members are not the only ones who have had this problem. There are other accounts of LED bulbs affecting radios, with AVForums also collecting stories. Nick Tooley shared his experience:

‘I had the same problems with LED bulbs wiping out DAB reception and tried several types of bulbs, but to no avail.’

And it seems that the issue may not just be limited to digital radios – TVs may also be affected. After fitting LED down-lighters in his kitchen, Jackord noticed the following problem:

‘While the lights are much better, we then by accident noticed that the digital TV would not work (I was complaining that we had no reception at all, did not make any sense, began to think that there had been some sort of catastrophic disaster which stopped the TV stations from broadcasting…lol) then someone turned off the ceiling lights in the kitchen and, hey presto, on came the TV.’

Shedding light on cheap bulbs

So what bulbs are affected? We tested three 12V generic LED bulbs and we also compared them to branded 240V GU10 LEDs and some halogens. We found only a very minor interference with our radio signal. So at this stage, the issue seems to be limited to cheap knock-offs rather than branded goods.

We’ve only done preliminary tests on this problem, so can’t make any concrete conclusions on why this is happening or how widespread this bizarre problem is.

That’s where you come in. We need your help – have you had this problem? If so, please enlighten us in the comments below, including what model bulb you were using and where you bought it.

606 comments

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wavechange

The June issue of the Which? magazine covers more LED bulbs than previous reviews, but I cannot see any mention of the problems of radio interference or premature failure.

Sometimes I wonder why we bother posting on these Conversations. :-)

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Phill taylor

Well I’ve just fitted lovely looking led bulbs to my down lights, even changed the transformers. Doing all this to a bit of smooth fm on my equally lovely DAB radio. Then I switch on the lights to test them and boom no radio, I instantly thought I’d wired the wrong but as everything else was on a soon realised that it was the signal. So I guess no radio during the hours of darkness…. Is there anything that can be done about this?

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SteveSi

Does the radio stop if all the bulbs are removed but the transformer is switched on?

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wavechange

Which? has still not tested 12V LED bulbs – the type that seem to cause most problems with radio interference. The report in the June 2015 covers only mains voltage lamps with a GU10 base.

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Diana P

We have this problem too – no radio during the hours of darkness. Kitchen lights even affect the radio in the bedroom. We use LEDlite code LED MR16 12V AC/DC. We are considering removing these expensive lights and going back to halogen ones.

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wavechange

Do contact your retailer and ask for a refund.

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Diana P

I have e-mailed LEDlite and asked for their comments on this.

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webbswonderful

Same problem; 6 LED lights in the bathroom. Digital radio in bedroom loses signal as soon as the bathroom lights are turned on. Gone back to halogen.

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busa

Have a lamp in a bedroom which has a 3watt led bulb, I was on my I pad and the light went off, I thought it may have been a black out, and put on the main light which worked fine,then the lamp came back on? Thinking it may be a problem with the lamp I wriggled the wires shook the lamp the lamp worked fine, it was then I noticed my wifi was down as well. Wifi and lamp at this point both work well. Is it possible that the wifi interfered with the chip in the led bulb?

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Tim Black

I replaced a number of downlighters (GU10 fitting) from halogen to LED (Phillips bulbs) last year.

Overally I am very happy (particularly as I had two prior halogen bulbs physically blow) but rather when the 4 downlighters in the bathroom are switrched on we lose all HD TV reception to our YouView box, non HD channels are fine.

I am going to try a few tests, one bulb at a time to see if its one particular bulb, or a cumulative issue. Furthermore I have a set of GE bulbs to trial too.

Its odd however as there are a number of other rooms in the house with the same bulbs and these have no effect when switched on.

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wavechange

The interference must be serious to affect a TV in another room, Tim. Is your YouView box fed from the router via the mains (power line networking)?

I would be interested in how your tests go. It’s well worth checking the bulbs individually to see if the problem is caused by a rogue lamp or, as you say, dependent on the number in use. Likewise, it makes sense to try the GE bulbs one at a time, so that you can return some of them unused if there is a problem.

I can understand why cheap unbranded lamps could cause problems but quite a few people have reported problems with well known brands of lamps.

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Diana C

I have just replaced 4 MR16 halogen bulbs in the kitchen with 4 MR16 5 watt (£6.49) LED bulbs. I am now getting interference with the DAB battery radio in the kitchen and analogue battery radio in the bathroom but not the analogue mains operated radio in the bedroom.

A few weeks ago I fitted a more expensive (£17) GU10 LED bulb in the kitchen and had no problem with the radios.

The cheaper bulbs say they are dimmer compatible but the expensive one is not. Is that relevant?

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wavechange

Diana – If you plough through the comments in this discussion you will see that there is more of a problem with 12V LEDs like your MR16 style than with mains voltage types such as the GU10 variety.

Interference falls off quickly with the distance between the source and the receiver, so there is less likely to be a problem with a radio in another room.

Your DAB and analogue (probably FM) radio are rather different, so you cannot really compare them, though it would be interesting to see what happens if you swap them over.

I suggest you should ask for a refund on your lamps that cause problems. If you decide to try a different brand, buy one to see if that causes interference before spending a lot of money.

Best of luck.

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Florida Panhandle

I’ve researched my problem with Wikipedia and the antennapoint webpage, a USA .com to find digital television transmitters (DTVs) nearest to your location, I “cut the cable” and use an outdoor omni-directional round antenna. Looks like what you might see on an RV. Fairly good reception.
I also use the made in China 20w outdoor LED IP65 110v-220v floods found on the online sites. TV reception problem has been intermittent with the light on near the antenna and mostly with only one channel. Placement at 1 meter or at 3 meters away from antenna is the same. But only one channel goes “Digital Signal Strength is Low” black HDTV screen. I do not have a reception meter in the HDTV or Any other receiver test equipment. So just trying things as I go.
I have problem with US band III VHF RF Channel 9 about Video carrier 187.25 (frequencies in MHz). Something like European Band III allocation E7 188-195 MHz, Irish E 182-190 MHz. My channel 9 is 2.3 kW power and about 33 Km away.
I’m thinking about experimental shielding with aluminum foil. See what I can do with the tinfoil hat
theory. Today its raining so no playing with electricity, Like to see what you guys think.

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Gerry

Not quite sure exactly what you propose to screen, but I doubt that aluminium foil will be successful: it might get a bit dark if you do it properly. Electrical filtering would probably be a better option.

You RV style omni-directional aerial doesn’t sound very efficient. I assume you’re trying to receive WPGX? You might even be getting interference from WALA (Mobile AL) on the same RF channel. Depending on the directions of the stations you wish to receive, a multi-element directional aerial may be better, ideally with a rotator. In practice, because digital TV doesn’t suffer from ghosting, you may get away with directing it towards a distant / weaker group of stations, and receiving stronger / local stations off beam. For example, in Davenport FL I can receive the Tampa stations (around 50 miles) with a loft (attic) aerial and get the Orlando stations (38 miles) on the back of the aerial.

Basically, if you start with a poor aerial system you’re more likely to suffer from loss of reception and / or interference. Of course, if you make the floodlight PIR activated, the LED interference shouldn’t be bothersome: you won’t be watching TV when you enter and leave your property !

Sometimes the info on Antennapoint can be out of date. TVFool (very detailed), Transition dot FCC dot Gov (good maps) and AntennaWeb (nearby stations only) may be better.

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Joe

Whilst watching TV with attached Bose speakers, I noticed that The remote to the speakers was not responding. I changed the battery without result. Tried moving closer to the tv without success. In the end, I gave up. In the morning , I tried it again and discovered that there was nothing wrong with it! I then put on the light in the room (energy saving 6 bulbs in a ceiling lamp) to do something else …and lo and behold the remote stopped working….switched off the lights …and it was fine. There is no doubt that the energy saving bulbs interfere with the transmission of remote control signals…very strange!!!!!!!!!!!!!!

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Hamgolfer

Slightly off-message but relevant to the radio interference topic, I purchased a 20W LED PIR security light, mains operated, to replace a less economical halogen type. Although it worked well it produced high levels of broadband radio frequency interference (RFI) on my amateur radio receiver, rendering short wave reception hopeless.

Investigation showed that the LEDs themselves were completely clean. The problem was due to a switched-mode power module within the lamp housing. This converts the mains AC voltage to 12V DC to drive the LEDs. I tried filtering all leads to/from the power module with good quality inductors and capacitors to no avail. Metallic screening also proved useless. Removing the power module and feeding 12V direct to the LEDs from an external transformer-based power unit proved a complete cure.

I then purchased a 12V input PIR LED security light and this proved satisfactory in all respects. Slightly less convenient to use an external power supply but no RFI at all.

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Martin G7MRV

I have LED MR16 bulbs which wipe out DAB reception. I tested one on its own powered by a lab grade variable PSU in my workshop and monitored its emissions using an Anritsu spectrum analyser.

The bulb was, generally, RFI clean, EXCEPT at almost exactly the UK DAB band! There was a huge noise level emitted between 200-230MHz.

Its simply a case that there is insufficient RFI filtering built into the bulbs, in order to save a few pennies at manufacture

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