LED & EMI - Anyone else notice?

[airstreaker]

I have a new 2017 FC & in the course of getting it ready I was recording a video inside and found enormous amounts of electromagnetic interference (EMI) shown as multiple rows (horizontal) across the image. Initially I thought it must be the power coming in, so I grabbed a UPS and ran the camera off of that...no change. Then I thought it must be the air conditioner... Nope... Anyway, I kept narrowing it down and accidentally stumbled upon the cause... Our new shiny LED lighting was dimmed... As soon as I brought the lights up to 100%, the EMI went away immediately.

After some very light Googling, it seems that EMI is a big problem with cheap LEDs.

EMI is not healthy and this is concerning to me. I have my entire family, baby, etc. in our new home full time.

Anyone else notice this issue with their unit?

Thanks

[Caffeinated]

"EMI is not healthy"

Following, with popcorn.

Mike

[rmkrum]

As a Ham radio operator and long time generator of lots of EMI, I'm making some popcorn as well....😀


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[mixedpuppy]

Microwave popcorn?

[Sorry, couldn't help myself with that one.]

[alano]

Light dimmers, when dimmed, are notorious for generating EMI, but the field strength emitted from these devices is generally very weak. The emitted frequency range is generally wideband and interfered with your video device. However, it's most certainly the case that the electromagnet fields created by your cell phone are orders of magnitude larger than the generated EMI from your dimmer. Epidemiologist have been studying the effects of electromagnetic radiation for decades with scant proof that it's harmful.

[airstreaker]

Wow, I'm pretty shocked by the sarcastic and mean spirited tone of the replies. I guess the Airstream community is not what I thought. I'll definitely think twice before ever daring to post again

[HiJoeSilver]

The dimmer is probably a pulse width modulator. It's basically turning your lights on and off at a varying frequency which causes the dimming effect in the lights. For example if the dimmer is set to 50% it's turning the lights on and off quickly so they are off 50% of the time. This may not be the exact ratio but it'll help you get the idea. It does this at a frequency that is imperceptible to most people.
The frequency is not imperceptible to video recording equipment. When you record video it does so in horizontal lines from top to bottom at a certain frame rate, typically about 30 frames per second.
So when the lights are flickering and the camera is recording it causes a strobe effect as the image is capturing individual horizontal rows.
You may be familiar with this same effect when you see a tv screen being recorded and displayed on another screen.
If you use your camera to record your tv you will see this but it won't be so drastic because the frame rates will be close to each other but not necessarily in sync. So you typically see a horizontal band that slowly moves down the recording video.
The frequency difference between the lights flickering and video tame rate will be higher which causes more horizontal distortion lines.
When you put the lights back to 100% there was no longer any imperceptible flicker, the lights were on 100% of the time. Which is why the perceptible flicker on the video went away.

Hope this helps you rest easier.

I won't scare you with technical EMI stuff, but the biggest thing you have to worry about in your AS is the microwave, which you really don't need to worry about as long as the door is closed when it's running, and your cell phone. All electrical circuits cause electromagnetic fields which can cause EMI. Any in your AS won't be enough to harm you.

Now if you really want to worry stay away from the SPY-1 radars on a navy ship. If you toss a bag of popcorn up in front of it while it's on the popcorn will come down popped and burned. Let's not get into birds flying in front of it. We turn it off well before we get close to land to protect people, plus it really messed up everyone's tv signal.

Caffeinated wouldn't be happy with that popcorn!

[HiJoeSilver]

Originally Posted by airstreaker

Wow, I'm pretty shocked by the sarcastic and mean spirited tone of the replies. I guess the Airstream community is not what I thought. I'll definitely think twice before ever daring to post again

Please note that very few people reply in mean spirit on the forums. As for sarcasm, it abounds but is almost always meant in a humorous light.

Hope my previous post helps put you at ease. Pulse width modulating is about the only way to dim LEDs, so I'm pretty sure this is what is occurring. Other methods of dimming LEDs would be way to expensive and large to use in an AS.

[mixedpuppy]

airstreaker, sorry, really, I couldn't help myself.

Seriously though, considering all the materials and technology involved; the tiny amounts of emi from leds is an insignificant health factor [giving a benefit of doubt here] compared to all the rare earth elements, chemicals, adhesives, ruber, oils, gas, mining, paving roads etc etc. are all inflicted on the environment in order to get to the problem of owning and using an airstream and being able to post issues about it onto the internet.

I'm not trying to be mean but I can see how it would be taken that way, so a sincere apology. I do understand heath considerations, just look up my thread on water filters We all have our thing.

[2012FB]

As stated I would not worry about the health issue. When designing our single element LED to replace a 150W Halogen lamp the EMF portion of the design was significantly the most time consuming and expensive aspect as we have to meet the latest UL and ISO standards for a medical device. With that said we have not experienced any normal use issues with ours but have not tried recording inside with the LED lighting dimmed. I am sure there are better dimmers on the market just like there are better replacements for most of the other low end gear on the trailer. Rest easy and enjoy.


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[HiJoeSilver]

EMI= electro magnetic interference. This is what is produced when electromagnetic fields interfere with one another and affect devices in a undesired way.

Electromagnetic fields and electromagnetic radiation are what can cause health problems. In order to cause health problems those fields have to be very strong. In order to create those strong fields requires very high voltage and amperage.

You won't find anything remotely close to those required in your airstream to cause you and your family health issues.

[mefly2]

Same EMI in ours - from the dimmer. Don't let the attitude of some keep you away.
This forum is a great resource.

[AIRHEDS]

Just ignore the sarcastic and negative posters. It's that simple. I'm a newbie myself and posted a few threads that resulted in feedback/comments that didn't necessarily contribute to the answering of my question, but it doesn't stop me from posting more questions. Maybe one day, I'll be able to answer as many questions as I post. :-) For every clown, there are hundreds of outstanding folks on the board and if you put the time in, you'll learn a whole lot about your new Airstream and its maintenance! Congrats on your new toy and may your family make many, many great years of excellent memories. And welcome to the forum!

[crispyboy]

Not sure if it is related or not but last year I installed two non-dimming LED fixtures over the sink/counter top area. Now the radio output has all kinds of noise when the lights are turned on. Is there any kind of filter that can help this issue?

[GammaDog]

For what it's worth, I didn't take the early replies as sarcastic or mean spirited. I sensed people were not aware of the issue, were concerned themselves, had nothing to contribute and posted something (intended to be) light so they get daily emails and can follow the discussion. The popcorn note meant they would be watching to see how this movie ends.

But maybe that just my interpretation.

[The Ice Man]

Originally Posted by airstreaker

Wow, I'm pretty shocked by the sarcastic and mean spirited tone of the replies. I guess the Airstream community is not what I thought. I'll definitely think twice before ever daring to post again

I've read them all and can't find a one that is "mean spirited." Mildly sarcastic, I'll give you, maybe a little hyperbole, true. But not, in my view anything "mean spirited." Like beauty, however, it is in the eye of the beholder.... or maybe the thickness of the skin.

PS Welcome to the Forum.

[Caffeinated]

I have been trying for a while now to figure out what to say to Airstreaker, assuming he will even read it, without sounding like an ass or mean spirited and coming up blank.

I am sorry I hurt your feelings. This is a pretty good community and you can get lots of questions answered about your airstream. I'm not too sure there are many emi experts though. I'm certainly not one. I'm also not too worried about it. What I am worried about are my Good Year Marathons. Those can do some damage.

All the best.

Mike

[HiJoeSilver]

Hope OP comes back and reads my response so he can sleep a little better with the family!

[cazual6]

Originally Posted by airstreaker

Wow, I'm pretty shocked by the sarcastic and mean spirited tone of the replies. I guess the Airstream community is not what I thought. I'll definitely think twice before ever daring to post again

Don't be. Just ignore the ones who are full of it. They are good people here.

Consider a ground issue. I have had mine with no issues. I had my LED's changed because after a year, some burnt out and some turned yellowish (soft white vs daylight) I believe they were roughly $40 per bulb.

[Alumineer]

Originally Posted by crispyboy

Not sure if it is related or not but last year I installed two non-dimming LED fixtures over the sink/counter top area. Now the radio output has all kinds of noise when the lights are turned on. Is there any kind of filter that can help this issue?

This webpage illustrates some of the radio spectrum interference that can be caused by some poorly designed LED controllers. Your best bet would be to buy a different light if you can, and to look for FCC certification labeling on the packaging and the product.

To the original poster: The interference illustrated in that webpage is a proper example of EMI, but the typical power levels (-60 dBm) are in the nanowatt range and are similar to FM radio signals. A cellphone causes more than a million times more radiation in your immediate area. The horizontal banding you saw in your video is due to the LED being dimmed at a frequency too fast for your eye to see, but such that the scanning of the camera can capture it and create a 'beat' pattern. So it's an optical effect and not a radio frequency interference problem.