Interference from LED spots

This morning I had S9+10 dB noise and splatter on all bands up to 21 MHz, crazy! I once suspected our 40″ plasma TV but this morning it was off so that can’t be the cause. Deep down I already knew LED spots also cause QRN / EMI but I never really got to tesing out what particular type was causing interference and in what degree.

Well let me tell you, one specific type is causing SUBSTANTIAL interference. It’s the type that replaced the halogene spots in my hall, kitchen and bathroom. Have a listen for yourself:

It seems that the LED spots the replace 230VAC halogene bulbs (in my kitchen) are causing most interference. They are of the “power LED” type. The same type in my bathroom running on 12VDC is causing a little less but still substantial interference. The LED spots that have those tiny yellow SMD LED’s soldered on a small PCB do not seem to cause any interference at all. It was my guess that it’s the LED type, but some local elmers tell me it’s the circuit that reduces the Voltage. Could be, but the 3 power-LED types in my bathroom running on 12V are still causing a lot of QRN so I’m not sure what the root cause is.

Here’s the type of spot that is causing substantial interference:


The smaller LED spots that have yellow SMD LED’s do not cause any interference at all:


I bought all LED spots from a Chinese seller on eBay. They probably don’t have CE certification but I’m pretty sure the first LED spots I bought came from a dutch online webshop that specialises in LED lighting (but probably got a bulk load from China).

If you hear the RFI that’s in the sample, chances are that it’s coming from LED lighting either from your or your neighbours’ house. As the SMD type is similar in price and doesn’t seem to cause interference, you might want to offer your neighbours replacement spots. The tiny yellow LED look a bit silly when the light is off, but when it’s on it looks pretty cool.


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