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LED Light EMI causing RF Mic interference


9 posts in this topic

Posted

I have been reading recently in TV Technology some articles or letters from people who are experiencing EMI interference from the new LED light bulbs that are starting to appear at Home Depot and other Hardware stores and lightning supply stores. These bulbs they tested emitted enough radiation out of the Bulb and associated wiring to knock ATSC channel 10 off the air in the vicinity of several hundred feet.. Frequencies in the 400 to 600 Mhz range were found to be emitted from the switching power supply contained in these bulbs.

Has anyone noticed this interference reducing Wireless Mic sensitivity in production situations where we are seeing more and more LED fixtures showing up?

Larry Fisher. Have you done any testing with spectrum analyzer to see if this will be an increasing problem in the future with more and more of these "dimmable" LED lamps being used in buildings or on sets? I just noticed all the streetlights in my neighborhood have been replaced with LED based lamps. Will this add to the noise floor of the VHF spectrum?

Apparently Part 15 FCC approval is really not policed and is really granted without testing on the honor system.

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Posted

A TV station I do some work for recently installed a bunch of these. I haven't seen anything show up on my RF Explorer.

I'd be interested in knowing which brands cause the problem, maybe not all LED bulbs?

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Posted

I have a few LED bulbs in my house. I'll have to see if I can find any interference. I think I have bulbs from two different manufacturers.

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Posted

My house is filled with LED lights, several different varieties from several different manufacturers. I don't have an easy way to do any testing (I certainly have not seen anything happen to my wireless the few times I have done some testing throughout my house.

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Posted

A TV station I do some work for recently installed a bunch of these. I haven't seen anything show up on my RF Explorer.

I'd be interested in knowing which brands cause the problem, maybe not all LED bulbs?

The Letter and Response in this Weeks TV Technology didn't mention a Brand name it just mentioned it was an LED Bulb purchased at Home Depot. I think it depends on the brand or manufacturer. I have seen demos on You Tube with several brands of bulbs and some are RF quiet and some are very RF noisy and radiate a lot of energy. The No-Name Bulbs tend to be the worst. Not popular brands at least. Here is an article on EMI from LED lighting written about a year ago.

http://www.emcrules.com/2011/07/radio-interference-from-led-lighting.html

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Posted

I am working on a show where the gaffer is using professional LED lights that are a replacement for the Kino-Flow Source 400. I have had to wire the talent almost entirely and I have not experienced any RF problems at all.

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Posted

Its interesting that you brought this up Courtney cause I was doing an A2 job last week where the gaffer used all LED lighting (Don't remember the brand) for a 3 person sit down interview in a very small room. The mixer complained of RF issues even though he was 15' away from all 3 talent. We did our due diligence in testing the wires out before hand but didn't verify the RF after lighting had done their jobs. We both ASSumed there wouldn't be any issues. Afterwards we both chalked it up to being at Universal but still, in the same room at a range of 15'.

On the next gig with this gaffer I'll break out my RF Explorer and see if the lights he uses puts out any RF.

Gabe

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Posted

I think lights and other AC power control devices are exempted from part 15.

LEF

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Posted

I was on a n interview job at a Doctors office in NYC a week ago and had a terrible high pitched whining noise that seemed to come and go at random.

Checked all my equipment, tried wireless to talent and the usual culprits in the office, fridge and computers and still there.

Finally asked the DP to temporarily turn off the Litepanels LED

lights that were from a rental house and the minute thee second light went off , of course the key,the whining noise went away .

Had time to plug the power supply from the whining light into the other side fill and vice a versa and it turned out to be the AC power supply of the offending light causing the noise.

Had to re-record all the interview lines with the lights off as they did not have any spares and it was after hours and rental house was closed.

Now on gigs with Lightpanels I check for AC noise right away and if I am consulted before the job strongly suggest using battery packs with them or at least asking that the rental house provide spare AC adapters with the rental package.

Aside from the above, in small space interview spaces with battery packs they are great, almost no heat and no lighting cables on the ground.

Andrew

Sent from my iPad using Tapatalk HD

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