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Author Topic: LED Lighting  (Read 21946 times)
AA4PB
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Posts: 12769




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« Reply #15 on: February 21, 2014, 11:37:11 AM »

AC originally won out because of the line loss issue. However, today look at all the devices that use transformers to either step up or step down the voltage to what is needed by the device. Imagine if your home had only 120VDC coming in. All those devices would now require some type of switching circuit to get its internal voltage to the required value. Each one then becomes an RFI source.

I doubt that homes will be changing over to DC service anytime soon. It would cause more problems than it solves. Perhaps some day the "home of the future" might have a single DC power supply for all of the permanently wired LED bulbs.
 
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KE7AXC
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« Reply #16 on: February 21, 2014, 08:12:14 PM »

There is work on DC in the home driven by all the devices that operate off DC and devices like solar panels that generate DC power and wasteful DC-AC-DC conversions.

Here is a link to one IEEE web page http://smartgrid.ieee.org/questions-and-answers/902-ieee-smart-grid-experts-roundup-ac-vs-dc-power

It may not be that far off, at least for new homes, but hard to say what will happen with existing buildings.

Alan
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ZENKI
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Posts: 911




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« Reply #17 on: February 24, 2014, 01:13:00 AM »

The EMC standards only measures the equipment on the assumption that nothing is connected to the device. The reality is that all the wiring because part of the  device and radiates. There are some moves afoot  by the EMC rule makers to consider the potential of radiation when the devices are connected in the world and how much radiation and noise comes from the associated wiring. An example is a solar system with multiple EMC sources connected by arrays of wires which act as antennas.

LED lighting and  solar inverters are becoming a nuisance that will be as bad as BPL if these laws are not changed.

The real problem is the all the fraudulent  EMC test marks that  can be bought by any company especially those from Chinese test houses.
Another problem is that a lot of industrial equipment such a pallet power supplies dont  have to prove that they wont cause problems when installed.
Very few installers know how to fix these EMC problems or install filters to stop the noise. A good example is the Meanwell power supplies.
Even if you had access to a EMC lab    and you were a EMC expert,  solving the interference to the ham bands with off the shelf hardware filters is next to impossible.
Yet they still produce such crap that will never pass the EMC laws in any country. When these power supplies are imported the  manufacturer should prove and document the filters and techniques that is available and that should  be used to make the power supply legal.  The power supplies should be tested with the recommended  filters.

It is not certain that these new laws will be adopted because of intense lobbying by the crap importers. I wonder why they have the ear of the politicians when there are design techniques that can be used to mitigate these problems. The answer is simple, they are greedy bastards who will do anything and at the cost  to  anyone.
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KJ4KPV
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Posts: 20




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« Reply #18 on: March 01, 2014, 04:31:30 PM »

We installed LED bulbs not that long ago and I was getting major RFI.  I didn't figure it out until my wife turned off the lights in another room did the noise stopped. 

I'm also getting some RFI at intersections with traffic lights that have LEDs and also those colorful LED signs from businesses...  lots of noise, especially on 2m.  It's only when I approach or pass by them that I have issues.  Even certain cars that use LED tail lights have created noise.  Otherwise, no issues elsewhere. 

I know it's not the LED's themselves, but the components that power them are.  We'll continue to see them pop up everywhere and grow in popularity.  It will become more of an issue in the near future. 

Jesse KJ4KPV
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WX7G
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Posts: 5948




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« Reply #19 on: March 02, 2014, 07:11:45 AM »

In the US 120 VAC LED lamp manufacturers can chose to be ENERGY STAR partners. As such these products have power factor correction and meet FCC part 15 conducted and radiated emissions.

Here is a link to an article I wrote on LED EMI.

http://issuu.com/eeweb/docs/lighting_electronics_-_jade_sky?e=7607911/6469021
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VE3FMC
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« Reply #20 on: March 02, 2014, 08:08:14 AM »

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. 

I have been using LED strip lights in my shack for 2 years, no problems with noise. I power them off the same supplies I use for my radios. I have two 6 foot lengths under one shelf, a 4 foot length under another shelf and a 5 foot length mounted on the ceiling above the operating desk. I can switch them off and still have the radios on and there is no noise from the lights.

I recently purchased 10 of these LED bulbs and have one in a ceiling light in my shack and 4 in my family room in pot lights. 2 in the bedroom and one in the hall light fixture. No RFI from them.
http://www.ebay.com/itm/181305371837?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
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VK3DWZ
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Posts: 37




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« Reply #21 on: March 03, 2014, 03:24:59 PM »

I don't know if this belongs here, or not, but these "new" energy saving electric light bulbs can, because of the circuitry contained within,  cause massive amounts of R.F.I. on the Broadcast Band.  I'm not sure if the R.F.I. extends up to H.F.  Luckily, altho' energy-saving bulbs are now mandatory in Australia I've never had this problem at our QTH.

However, when a lot of these bulbs were given away free up in Sydney, many people could no longer receive the BCB unless they turned their lights off!  I can imagine they were manufactured in a certain Asian country renowned for turning out junk.  All ours are manufactured there and hardly have any life at all despite costing many Dollars each.
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WX7G
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Posts: 5948




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« Reply #22 on: March 04, 2014, 07:22:51 AM »

VK3DWZ, consumer electronics is having a similar impact on the U.S. AM broadcast band. This article in the N.Y. Times mentions the interference caused by consumer electronics.

   http://www.nytimes.com/2013/11/02/business/media/fcc-plans-sweeping-changes-to-bolster-am-radio.html?_r=0


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KF7CG
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Posts: 826




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« Reply #23 on: March 04, 2014, 10:00:27 AM »

On the DC power side of this, if one does a little searching on this they will find that there are multiple very high voltage transmission lines across the western U.S. These are use to reduce line loss and mitigate some of the insulation requirements. Remember it will take at least 1.4 times the voltage rating for AC as DC. Also with very long transmission lines the radiative and parasitic losses tend to grow.

The western DC transmission lines are technology from the late 1990s and early 20000s but they have never been widely publicized. So Edison was partially vindicated.

KF7CG
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G7MRV
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« Reply #24 on: March 13, 2014, 09:46:32 AM »

I have been meaning to deal with an RFI issue with my LED MR16 12v lamps for sometime, and have today started to do so. I will share my discoveries as they may be useful.

Let me point out to start with that my lamps are 20 LED, 12v DC MR16 types, fed with proper LED driver PSUs.

The RFI issue from my lamps is directly affecting reception of DAB radio at 220MHz. Monitoring on a spectrum analyser and with one of the lamps fed by clean pure DC (from a battery) showered a peak of RFI from 220 to 300MHz. Everywhere else looked clean.

These lamps contain a boost regulator, and it is this that is the cause of the RFI.

Putting a 100nF ceramic capacitor across the lamps terminals, as close as possible, drastically cut the observed level of RFI, and made reception of DAB possible within inches of the lamp.

Such a cap would be required across the terminals of each of these lamps in use. Because of the relatively long cable lengths in a domestic installation in relation to the wavelength of the RFI, ferrites close to the lamps are also likely to be needed to completely solve the problem.

I have refitted one 'modified' lamp in a circuit of three, and the level of RFI is definitely reduced. I still need to do the other two lamps and to add the ferrites.
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KC9YTJ
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Posts: 62




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« Reply #25 on: March 13, 2014, 09:57:49 AM »

I was able to cut S5 noise on 6 meters to S2 by the simple expedient of turning off the floodlight fixture above my shack desk.

Couldn't figure out where all the noise was suddenly coming from until I remembered I'd changed out the incandescent BR40 flood with an LED replacement we picked up at Costco the other week.  If you want to avoid these, they're FEIT Electric 100 Watt LED Replacement BR40 Floods, Costco item number 795262.  And yep, made in China.  Sigh.
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ZENKI
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Posts: 911




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« Reply #26 on: March 14, 2014, 04:05:00 PM »

The most horrendous LED lights that I have come  across are these LED floodlights. They becoming very popular in rural/country/farm areas. They horrific RF jammers.
Installing line filters chokes and trying everything I could not even reduce the interference by 3bd. They just nasty poorly designed equipment that  have fraudulent EMC marking. They will  take out most of the HF from 50khz to 50mhz.

http://www.ebay.com/itm/10W-20W-30W-50W-LED-Flood-light-Outdoor-Landscape-Lamp-/171051394078?pt=LH_DefaultDomain_0&var=&hash=item27d375241e
http://www.ebay.com/itm/10W-20W-50W-100W-LED-Flood-light-White-High-Power-Waterproof-Outdoor-lights-/251152523842?pt=LH_DefaultDomain_0&var=&hash=item3a79db6242

From 2 kilometers away one of these 50 watt LED floodlights raised the noise floor on 160meter from S1 to S5, that how powerful the jamming and noise is.
From 1 kilometer away in my mobile on 20 meters the noise was S9.

These lights are really a ham radio show stopper. They are illegal under the current EMC laws however they are still be sold online and  being imported by the large retail chains. The authorities dont care and are not interested in prosecuting the importers of this chinese crap. If a local company sold products like these they would be shut down. The chinese importers and their importers seem to have a lot of sway in  getting a blind eye turned towards their  criminal behavior
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