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Author Topic: Outdoor LED Lighting RFI  (Read 3234 times)
KL0S
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Posts: 143




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« on: November 03, 2017, 07:31:03 PM »

My neighbor recently installed four 80W outdoor LED light fixtures manufactured by "Bobcat Lighting" which are about 125' away from my SteppIR BigIR vertical and when on simply tear up the HF bands with at least a +10 signal. He has been very cooperative and helped confirm that they in fact are the culprit by switching off each circuit at his panel while I monitored for the noise. Fortunately he only uses the lights for a short time when he's out taking care of his farm animals.

Bobcat Lighting is a U.S. company and I contacted them and provided my experience. One of the managing partners told me that his engineers guaranteed that their units meet FCC EMI standards but offered to have the lights tested if my neighbor would remove and ship them to him. Of course my neighbor needs his lighting...I've offered to purchase four new lights and have them installed -- but I have to find the most RF quiet outdoor LED fixtures to do so.

Does anyone have any suggestions for a manufacturer who makes RF quiet units?

Thanks in advance!

73 - Dino KL0S
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ZENKI
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« Reply #1 on: November 04, 2017, 01:37:44 AM »

I would suggest you try a few of these.

https://www.ledvance.com

This company is owned by OSRAM.  I have tested their LED Floodlights upto 50 watts. Very bright and QRM free when installed in my neighbors  house to replace the Ebay LED floodlight jammers. In fact most of the so called name brand LED floodlights cause horrendous  QRM. Its not the LED lights but the power supply drivers that are cheap Chinese junk with fake EMC and Standards markings.

The LEDVANCE lights have been the lowest QRM  LED LIGHTS that I have come across when installed away from my station. When installed in my station i detected minor noise on 18mhz that could be easily killed with a ferrite choke.

I measured these lights using a LISN and they are clean. I can only vouch for the 20 and 50 watt units.
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N6PJB
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Posts: 61




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« Reply #2 on: November 04, 2017, 09:31:01 PM »

Stay away from Ledmo LED fixtures as they also produce too much EMI.
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NK7Z
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« Reply #3 on: November 05, 2017, 05:45:50 AM »

Remember, what was true yesterday, may not be true today...  Manufacturers tend to source parts and PC boards from various other folks all the time, and the sources change...  Changed sources can equal RFI on what was an otherwise RFI quiet device.  Buy what you think best, buy it with the ability to return it if it generates RFI, then test it.  That is your ONLY way to insure you get an RFI free device. 

BTW, The FCC specs say that a lighting device can't interfere with your licensed use of the radio.  See:

https://www.ecfr.gov/cgi-bin/text-idx?SID=833fffb55cebfced8d061b986f371e7f&mc=true&node=se47.1.15_15&rgn=div8

and

https://www.ecfr.gov/cgi-bin/text-idx?SID=833fffb55cebfced8d061b986f371e7f&mc=true&node=se47.1.15_115&rgn=div8

So in your next discussion with the company making the device, and if you feel the need, you now can point out that the device is not in compliance with part 15 when used, if it is harming your use of the spectrum.
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Thanks,
Dave
For reviews and setups see: http://www.nk7z.net
N1LO
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« Reply #4 on: November 06, 2017, 05:54:19 AM »

Hi Dino.
 It sure sounds like you got a brush off from the Bobcat company. Maybe you could just send one of the lights back for testing. Perhaps a short video using a baby monitor set at the shack and including a view of the LED light switching on with you holding the baby monitor receiver showing how the noise instantly comes up.

It might even be worth trying to place a field strength meter next to the LED fixture or wire and switching it on and seeing if you measure stray RF radiating off the AC line or device. Send a video of that to the manufacturer and there is no doubt.

So frustrating to see common consumer electronics destroy our Hobby.
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KL0S
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Posts: 143




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« Reply #5 on: November 23, 2017, 05:35:44 PM »

Continuing this saga...neighbor was nice enough to pull one of the fixtures down so I could do some testing on the bench and the spectrum analyzer with a H-field probe showed significant energy up to around 10MHz radiating back down the AC leads. Threw some snap on ferrites on the three power wires and reduced a lot of the energy above the ~2MHz peak. These plots and a short video of the noise going to the manufacturer tomorrow...the power supply PWM signal is most likely the culprit and the long AC runs to the fixtures are simply acting as long antennas. So we reinstalled the fixture with ferrites and added three to the other fixture. When the lights came on at first the noise was down from +10dB to almost zero...boy thought my problem was fixed. BUT as the lamps heated up the noise did as well, rising over about 10 minutes from S1 to almost S9 (before ferrites it was 10-15dB over S9). Hopefully that's another clue for their engineers to chew on; we'll see what they say. More to follow...

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AE5GT
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« Reply #6 on: November 24, 2017, 08:22:54 AM »

Continuing this saga...neighbor was nice enough to pull one of the fixtures down so I could do some testing on the bench and the spectrum analyzer with a H-field probe showed significant energy up to around 10MHz radiating back down the AC leads. Threw some snap on ferrites on the three power wires and reduced a lot of the energy above the ~2MHz peak. These plots and a short video of the noise going to the manufacturer tomorrow...the power supply PWM signal is most likely the culprit and the long AC runs to the fixtures are simply acting as long antennas. So we reinstalled the fixture with ferrites and added three to the other fixture. When the lights came on at first the noise was down from +10dB to almost zero...boy thought my problem was fixed. BUT as the lamps heated up the noise did as well, rising over about 10 minutes from S1 to almost S9 (before ferrites it was 10-15dB over S9). Hopefully that's another clue for their engineers to chew on; we'll see what they say. More to follow...



Its hard to get more than about 30db suppression with just adding ferrites. You might actually have a faulty light ? I would notify the ARRL They may wish to get one and verify the results . In the past they have shown some interest in at least exposing the problem .
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KL0S
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Posts: 143




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« Reply #7 on: November 24, 2017, 08:29:16 AM »

I have corresponded with Mike Gruber W1MG at the ARRL lab and may arrange to have one examined further. The snap-on's were simply a test to see if the energy could be reduced at least somewhat. As the test light I looked at on the bench did not exhibit the temperature issue I'm starting to thing that the 2nd lamp is in fact the culprit. Going to ask the company to send one hopefully known good replacement to swap with the suspected fixture. Thanks for the thoughts, working on my e-mail to the company right now. 73 - Dino KL0S
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ZENKI
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« Reply #8 on: November 24, 2017, 08:02:40 PM »

Let me tell you that ferrites are almost useless when you come across a LED light that has not been designed properly. I even tried proffesional EMC mains filters with 60 and 70 db  attenuation.

You have 2  paths for the interference. Radiated and conducted.  Every is just assuming that the interference is conducted down the mains cable and the ferrite is a magic bullet. Its not.  A lot of the time the switchmode DC converters are badly designed spark transmitters that jams the spectrum from daylight to 200 mhz in my experience and even the best ferrite in the world is not going to stop radiated emissions.

These LED lights need to comply both with radiated and conducted emissions. The ones you typically find on Ebay meets none of the radiated and conducted emission standards and are so powerful that you can call them radio frequency jammers the interference is so bad.

Even shielding and  ferrite will not stop these badly designed products and in the case of LED lights and floodlight you will learn this  the expensive way  by spending a lot of money on ferrite that achieves very little.


I have corresponded with Mike Gruber W1MG at the ARRL lab and may arrange to have one examined further. The snap-on's were simply a test to see if the energy could be reduced at least somewhat. As the test light I looked at on the bench did not exhibit the temperature issue I'm starting to thing that the 2nd lamp is in fact the culprit. Going to ask the company to send one hopefully known good replacement to swap with the suspected fixture. Thanks for the thoughts, working on my e-mail to the company right now. 73 - Dino KL0S
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N1LO
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« Reply #9 on: November 25, 2017, 06:02:11 PM »

Interesting saga Dino. Sounds like you have achieved good relations with the neighbor, and he is sympathetic. That's half the battle.

Is there any room to shoehorn some .01uf/1Kv disc ceramic shunt caps inside the fixture in addition to ferrites?

Good luck
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KL0S
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Posts: 143




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« Reply #10 on: November 25, 2017, 06:14:02 PM »

Hi Mark - didn't get a chance to disassemble the fixture as I wanted to get it back to my neighbor before dark! If the company responds positively I may get the opportunity to do a bit more experimentation when we swap them out. Yep, it's really nice that my neighbor is so cooperative...he's a good guy.
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WB4SPT
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« Reply #11 on: November 26, 2017, 11:34:42 AM »

I was able to fix an emissions issue with a led driver dc-dc step down switcher.  It was actually ONLY a pcb layout issue. Brought down rad emissions about 20 db.
What fixes one design doesnt always apply to another though. 
The high power led outdoor designs ive seen use off the shelf 12 or 24 v dc supplies. They SHOULD already be clean but many are not.     
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