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Author Topic: LED Lighting  (Read 23176 times)
DWEBB5
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Posts: 8




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« on: January 23, 2013, 04:34:26 PM »

We were discussing some of the new efficient lighting that are coming out, mostly the LEDs.

"But I wonder if they've solved, or cured the RFI problem. The more powerful ones I use, knock out FM radio and the Fire Department radios if they're anywhere near them:(
http://news.bbc.co.uk/2/hi/programme...ne/9782116.stm  "

" Some REAL numbers on them: http://www.kickstarter.com/projects/...u?ref=category
NanoLight - The world's most energy efficient lightbulb!
"Why use any old lightbulb when there’s the NanoLight! Using only 12 watts of electricity, the NanoLight generates over 1600 lumens, equivalent to a 100W incandescent lightbulb."  "

"   one... http://www.triplepundit.com/2011/01/...troducing-esl/
Higher power factor than LED's  "


Now the topic of RFI has entered the picture.  People are complaining that the LEDs are causing problems with  scanners, and local VHF radios.
Question:
Does anyone here use LED lighting IN the Ham shack?    Any trouble?  Feedback?    Ever hear of this before?   Thanks in advance all, David
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K1TWH
Member

Posts: 103




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« Reply #1 on: January 23, 2013, 05:40:19 PM »

___I've got a number of RFI free LED bulbs in my home, but I did send a few from eBay vendors to ARRL.  They were unbelievably noisy.  How so much noise could come from such a small object was amazing.   Quiet bulbs were from GLB (used to be @ Cyberguys) and Miracle Bulb.   The Miracle bulbs are stroboscopic like fluorescent bulbs, so 100% use of them cannot be recommended for families with members that are sensitive to flashing strobes. 
___I'd say buy from reputable vendors and return them if there is RFI.
73,  Tom WB1FPA
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K6AER
Member

Posts: 3518




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« Reply #2 on: January 25, 2013, 07:45:06 AM »

LED lights don’t emit any RFI. It is the power supply that is pulse modulating the LED that is generating the radio interference. A led light has a narrow window going from dark to full brilliance. By pulse modulation and varying the plus width the average brilliance can be efficiently varied. I an effort to provide the most efficient light the pulse shape is very square which generates lots of RFI due to its fast rise time.

Probably most of the RFI is being radiated in the house wiring. You might try some snap on RF beads where the wiring goes into the light socket.
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DWEBB5
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Posts: 8




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« Reply #3 on: January 25, 2013, 03:02:49 PM »

So if I used low voltage DC instead of a power supply, that would eliminate the RFI caused BY The power supply?

Still using AC and the LED light the other option is below.
Adding the choke AT the LED light would eliminate the noise in the rest of the house wiring. So any radios would be unaffected.
http://users.catchnet.com.au/~rjandusimports/tut_9a.html  <-- That's an RF bead Right?
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ZENKI
Member

Posts: 938




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« Reply #4 on: January 28, 2013, 11:40:56 PM »

The LED lights to watch out for are these. If you get one of these near your ham radio days are over from 1.7 to almost 150mhz. These are legal 10 to 50  watt broad spectrum jammers.

http://www.ebay.com/itm/10W-LED-Flood-Light-Floodlight-Lamp-Warm-White-Garden-Outdoor-Lamp-/121057218689?pt=LH_DefaultDomain_0&hash=item1c2f929081

They sold by various ebay sellers and as re branded  versions in stores. They have no EMC compliance whatsoever. This is a disaster for the broadcast and ham bands and they just flowing
into countries around the world from China.

Its astonishing that such a product can be legal to sell anywhere when it causes so much interference. The QRM will be 40 DB over S9 if you used one and something like 20db over S9 from
a neighbor. As usual the people paid to enforce the EMC laws just turn a blind eye to this crap from China, and users of the radio  spectrum who pay a license fee get ignored. A sad reflection on how are societies are allowed to
operate these days.  What I can never understand is that manufacturers who produce products like these in their own country would suffer the full consequences of the law and have to spend countless hours and dollars
meeting these EMC requirements. Then on the other hand importers and ebay sellers can flout all these laws to the disadvantage of legitimate manufacturers who meet the EMC standards.

These LED lights are worst than things like plasma TV's and on a band like 80 meters where signals are very strong you wont hear a thing.  If you were a facist regime or  a dictatorship like North Korea and you want to jam
as much of the HF spectrum on a budget you would install this type of LED light. If you see these around please report them to your radio society EMC committee, you will hear them!
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ZENKI
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Posts: 938




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« Reply #5 on: January 28, 2013, 11:53:01 PM »

There was story on Eham about LED lights from a shop jamming the Swedish Bus VHF radio network.

This is a real serious issue that most authorities are just ignoring.

The whole issue of radiated emissions from things like Plasma TV's, Solar Inverters, MMPT regulators/panels and LED lights need to be looked at and new standards developed.
The  EMC laws are just not keeping up.
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W8AAZ
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Posts: 346




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« Reply #6 on: January 30, 2013, 03:10:27 PM »

Great. I was gonna try some LED bulbs but don't want to front the big money and then have headaches.  I suppose that most people are happy as long as their wifi and cellphones are not messed with. Or if they are, probably no clue as to what is going on and blame the service or the equipment.  And I wonder what is the source of my constant S8 background noise on some bands, assuming if it is neighborhood home devices, I probably have no recourse, or with them putting digital whatsis into everything made now, could never hope to keep up with fixes anyway. 
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K0JEG
Member

Posts: 665




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« Reply #7 on: February 04, 2013, 06:07:10 AM »

Just passing along LED lighting that doesn't put out RFI out past a few inches.

Sylvania RGB LED strip lighting, picked up over the weekend at Costco. Comes in 4 2' lengths that interconnect, 12V, 2A wall wart and an IR remote box. I couldn't detect noise with my FT-817 (using stock antenna) until it was about 4-5 inches from the strip, and then only on 40 and 80 meters.
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AB4ZT
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Posts: 172




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« Reply #8 on: February 04, 2013, 04:15:03 PM »

We are steadily replacing all of our incandescents and CFLs with LEDs and have no issues whatsoever. 

73,

Richard, AB4ZT
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AA4HA
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Posts: 1450




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« Reply #9 on: February 05, 2013, 05:17:04 AM »

LED lights don’t emit any RFI. It is the power supply that is pulse modulating the LED that is generating the radio interference. A led light has a narrow window going from dark to full brilliance. By pulse modulation and varying the plus width the average brilliance can be efficiently varied. I an effort to provide the most efficient light the pulse shape is very square which generates lots of RFI due to its fast rise time.

I guess this needs to be restated and reinforced. "An LED does not emit any form of RFI". If you ran your house off of DC power you would have absolutely zero EMI/RFI from lighting.

Any problems you are having are caused by lousy designs in the power conversion circuitry to bring 120 VAC down to DC voltage levels or in some pulse modulation schemes to do things other than running an LED off of a pure DC voltage.

If you bought a box of LED's and current limiting resistors and wanted to string them together as LED lighting you would have one of the electrically quietest forms of illumination possible other than a heated filament bulb but many times more efficient.

Companies that design in el-cheapo power supplies and conversion schemes should "be beaten with sticks".

I wired my house when it was being built with a secondary DC power system with 12 volt, 2 amp circuits at a bunch of auxiliary outlet plates where I also can connect into shielded audio cable, Ethernet or multimode fiber (only used in two places right now but the capability is always there for more fiber, just add connectors to the existing glass). The DC lighting also has the advantage of being connected through breakers to a big set of batteries so during a power outage the only thing I notice is the beeping of UPS'es for things that still require mains power.
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
ZENKI
Member

Posts: 938




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« Reply #10 on: February 06, 2013, 03:19:33 AM »

A  very good point. 

The point is that  EMC laws that govern power supply products need urgent revision. There are numerous examples of switch mode  power supplies on just about every conceivable device causing  RFI problems. Even Applies Iphone charges are horrendous QRM producers across many ham bands. Now if a company like APPLE has lousy EMC advisors, what hope is their for these small companies who produce these LED products that causes massive  HF interference.


LED lights don’t emit any RFI. It is the power supply that is pulse modulating the LED that is generating the radio interference. A led light has a narrow window going from dark to full brilliance. By pulse modulation and varying the plus width the average brilliance can be efficiently varied. I an effort to provide the most efficient light the pulse shape is very square which generates lots of RFI due to its fast rise time.

I guess this needs to be restated and reinforced. "An LED does not emit any form of RFI". If you ran your house off of DC power you would have absolutely zero EMI/RFI from lighting.

Any problems you are having are caused by lousy designs in the power conversion circuitry to bring 120 VAC down to DC voltage levels or in some pulse modulation schemes to do things other than running an LED off of a pure DC voltage.

If you bought a box of LED's and current limiting resistors and wanted to string them together as LED lighting you would have one of the electrically quietest forms of illumination possible other than a heated filament bulb but many times more efficient.

Companies that design in el-cheapo power supplies and conversion schemes should "be beaten with sticks".

I wired my house when it was being built with a secondary DC power system with 12 volt, 2 amp circuits at a bunch of auxiliary outlet plates where I also can connect into shielded audio cable, Ethernet or multimode fiber (only used in two places right now but the capability is always there for more fiber, just add connectors to the existing glass). The DC lighting also has the advantage of being connected through breakers to a big set of batteries so during a power outage the only thing I notice is the beeping of UPS'es for things that still require mains power.
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K1DA
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Posts: 507




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« Reply #11 on: March 14, 2013, 09:33:06 AM »

Roybi battery powered tool chargers can be REAL annoying. 
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VE6PDB
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Posts: 5




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« Reply #12 on: February 21, 2014, 07:57:50 AM »

I was reading National Electrical Code for the DC voltage wiring for houses, so it is coming. I agree it would likely be much more quiet, though the code is allowing for the transformers to be in boxes (hopefully metal) instead of requiring them to be centralized.  I was wondering about the diodes demodulating AM signals and putting them onto the house wiring etc. and whether that would end up being a problem.

Ah well, I'll be taking my LED desk lamp home in the next week or so and will be trying to do more HF, so I may have more to report soon on my experiences!  Perhaps if someone were to design an inexpensive, but efficient, pulse modulated (dimmable by changing pulse width), but RF quiet by using a rounded wave instead of square wave (or good shielding over the square wave portion) and put it into the public domain....

I wonder if I should head down this road myself Smiley Run my 52A 12V power supply to one of those boxes that charges batteries and switches to them when the power goes off from the power supply and run not only my rigs, but a bunch of LED lighting off of that setup. Bypass the power supply if it's internal and run it straight off of the DC. I had an outside light that was LED and it worked quite well.
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AA4PB
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Posts: 12854




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« Reply #13 on: February 21, 2014, 09:11:56 AM »

DC power for homes?Huh I thought Edison lost that battle years ago. The problem with DC power is that you can't step up the voltage or efficiently step down the voltage without chopping up the voltage to make AC and that is what generates all the RFI coming from low cost switching supplies.
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KD0REQ
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Posts: 947




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« Reply #14 on: February 21, 2014, 11:13:36 AM »

you have LOTS of DC powered iThingies at home.  you are just not running long wires to them and seeing the resistive drop.

Edison's deal was this:  you run DC, you can't keep the voltage up more than 3 miles.  so you sell a tubload of generating plants into the system and make more profit.  which eats up a lot of real estate and you can't really build a grid of networked power stations to maintain reliability.

Tesla's AC design work had one big advantage: you can put AC through transformers, reduce the current flow over distance, and have less R loss.  so GE had to change strategies as Westinghouse ate the market.  although we had a DC power plant in downtown Fargo into the 60s that powered downtown shops and apartments.

Tesla also had some other funny ideas, like putting half-million-volt lines into homes and making the lights and motors run from static in the air.  that was his kit of parlor tricks that made him money in lectures after he sold his patents.  most seriously freakin' dangerous stuff, that, as those of us who got bit by a future PhD's 300,000 Tesla coil in his damp basement found out.  sometimes from a distance.
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