The energy-saving LED bulb that switched off the radio
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?
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.
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David Farnell
I purchased a small DAB Roberts Ecolological 1 radio to use in our bathroom, it is not yet installed in there, but sits in our kitchen area, about 3 metres away from the bathroom LED light transformer. Every time the bathroom lights are turned on, the radio mutes or plays snippets of sound accomapanied by a sort of squelch. I installed 5 x 4W LED lights powered from a eSmart Germany Universal Transformator Leistung: 0 – 20W 1,67A DC12V AC90~250V IP67 dust- and water proof transformer unit.
I thought that the cause of the problem was more likely due to the 12V transformer unit in the ceiling, although I recently purchased an ARCH AC-DC Converter 20W unit and fitted it with a mains plug. When this is turned on right next to the radio, nothing happens, although it has no outward load.
I read with interest some of your reader comments about desk and bedside lamps causing problems. I have a computer keyboard 240V LED light that does nothing, neither does a 12V LED running off a non rectified voltage transformer in the base.
Two other Roberts radios are affected by the lights in the bathroom in a similar way.
Robin Caine
Following my earlier posts I have now carried out some tests. I have an older DAB Radio adapter which tunes automatically to the 225MHz multiplex. I cut a tuned dipole, at least as good as an internal antenna, for this frequency and measured the DAB signal strength on a spectrum analyser, which gave a voltage of about 30 microvolts at the antenna terminals. When I switched on the LED lamps (12 volt MR16 replacements) in the ceiling above, the interefering signal was rather greater at that frequency, and consisted of pulses of noise sweeping across the DAB band and far out each side.
On connecting the receiver, it operated very well (free of errors and ‘garbling’) without the lights. Switching on the lights killed any reception at all, regardless of moving or swivelling anntennas.
I repeat that running the (MR16) LEDs from a Gelcel made little difference – it’s not the 240/12 Volt inverter/transformer (although the radiated noise does come from the 12V wiring).
There is no doubt that:
12V MR16 LED downlighters are incompatible with DAB, even when they meet EC standards.
The Mains powered GU10 type of the same wattage range are practically clean.
DAB is designed to work well on internal antennas and are meant to be a big improvemnet on VHF FM.
The powers that be, ie OFCOM, must resolve this issue by requiring higher field strengths for DAB, tightening the radiated emissions standards for switched devices. Given the obvious need to save energy, I suggest that urgent action is needed.
Robin
wavechange
Thanks for the update, Robin. Where did you hear that DAB is intended for use with an internal antenna? My experience is that neither DAB or FM signal strength is adequate in many places, and often one will work where the other is inadequate.
Obviously there is scope to increase transmitter power but that could result in a different form of interference, caused by the radio signal.
Fred
We had a bad thunder storm here earlier this week and noticed that our NOAH weather alert radio did not give any warning. The radio is located on a wide window sill in the kitchen area and gets very good reception. Later that evening another bad thunder storm arrived again with no response from the weather radio which we have mainly for tornado warnings.
After checking the radio and making sure it was set properly I placed it back on the window sill and turned it on test and discovered it was all static. I then tried to tune on all the weather NOAH stations and they all were nothing but static. I was frustrated at this point. About that same moment my wife turned off the kitchen lights which are 65 watt incandescent flood lights in the ceiling. Except for one LED which I just installed a week ago or so. When the lights were turned off the static on the radio disappeared and the station was load and clear. As soon as the lights were turned on the static appeared and the station was cut off.
This could be a real problem if a tornado alert is not picked up.
The Bulb is by UTILITECH PRO a BR30 indoor flood 650 lumens 2700K uses 12.5 watts item no.
0338929 model # UHLBR3012W27K
Fred
Claire Davies
We have a very old music centre, but as soon as the ceiling lights were replaced in our kitchen, we now find we cannot use the radio at all. We are wandering around in stigian gloom while trying to cook. Should we cut ourselves, who can we blame>
I was horrified that the electrician, finding the fault at the time of installation, did not immediately take the d… things out.
David Farnell
More information about the lights we are using:
The bathroom have 5 x Aurora 4W 12V MR16 Super Bright LED Light Bulbs|Warm White, 3000k run from a 20V transformer-circuit. We also have 240V LEDs in the kitchen, and used to have those in the bathroom. They do not seem to cause a problem. I purchased the Aurora LEDs to fit in the bathroom of a property that I let out and the first 4 bulbs needed to be fitted the correct way (as real LED electronic ones do), so I had to mark each connector with a blob of red paint. This was not needed with the later batch of Aurora LEDs. Another point of interest by another person on these pages suggested that the wiring could be an issue? Wouldn’t an earth screen help the cables?
wavechange
I suggested screening on the previous page, since it is a fairly obvious solution. It would be interesting to know whether screening either the wires or power supply has an effect. Obviously it is vital that the earthing is done properly and cannot come in contact with the live/neutral conductors.
Malcolm R
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 paraphrase this from their literature, but it highlights that even with quality components problems can result – so even more problems likely with poor quality components. Worth buying mainstream equipment if you can find it.
wavechange
Most of the compact fluorescent lamps that I have seen have been branded with the name of a well known manufacturer or retailer. With LED lamps, there are numerous unfamiliar brands and Internet traders.
I am quite happy with my CFLs for the time being. If I do buy LED lamps I will go for known brands, purchased from an established retailer. Avoiding radio interference is one reason, but safety is rather more important to me. Thanks to Internet trading, a lot of dodgy electrical equipment is coming into the UK.
Tom
Having read your article in the April 2013 edition of Which? entitled ‘Are your LED lightbulbs affecting your radio?’ I thought I should let you know that I have experienced this problem since replacing the spot bulbs in my kitchen some months ago. I have not received any reception for sometime on my radio and I’m thinking now that it may be the bulbs that are causing the problem. I get a constant loud buzzing/crackling noise and whilst I’ve tried many functions that I thought would solved the problem – this has not worked.
The bulb brand is; Diall 12v/40w and with code; MR16 1267/ R12 W26.
I hope this information helps somewhat in any future/further investigation you may wish to conduct.