Light Bulb RF Noise

[WD8BIL]

Had a chance to run some scans on the new bulbs of the future. This sample I have is a sylvania 23 watter (blue trace). The red trace is a 100W GE normal light bulb.

The lower limit line is the FCC Part 15 Class B limit for conducted noise.

[WA1GFZ]

Holy crap that sucks
40 dB uv is about S9

[AF9J]

You know something, that makes sense.  My apartment building has mini flourescents (you know, the ones that are meant as replacements for incandescents in your lamps, etc,).  My noise level is at least 10 to 15 over 9! on 80 & 160, and even S6 to S7 on 20m!  That's awful!

Ellen - AF9J

[flintstone mop]

Oh My Gawd
I found an under the shelf flourescent wipe out 160M, from a next door neighbor 50 feet away! The lady was very cooperative even though I wiped out their TV when I was on 80M AM. A simple common mode filter on the VCR took care of that.
Fred

[WA1GFZ]

WOW Fred,
I was planning under shelf lights in new place guess I'll buy a low voltage LED system.
This is worse than BPL

[k4kyv]

Makes me glad that the nearest house from me is over 500 ft. away.

I tried a compact fluorescent in the shack and immediately yanked it out as soon as I heard the noise.

I think I'm still getting QRM from someone's touch lamp.  It's weak, but puts an annoying birdie right on top of the AM signals I hear near 1985, and another one falls right on 1885, plus additional ones about ever 50 kHz from BC band up past 3 mHz. I hope my 160m signal is making the thing go spastic whenever I transmit.

They have loads of made-in-China touch switches in stock at Lowe's and Home Cheapo.  Not a single one of the damn things has the required FCC Part 15 notice attached.

[W1RKW]

That's strange.  80% of the lights in my household have compact flourescents lights (CFL). With the exception of one CFL I have  no noise on my shack receivers.  The dimmer on the chandelier in the dining room on the other hand is the biggest offender.

[wb1aij]

Boy, the Hams in the days before electricity was invented were LUCKY. Imagine how quiet the bands were before lights,motors, VCRs, TVs, and all of those other noise generators. Must have been nice.

[Tom WA3KLR]

I have some of the CFLs here.  I did notice the RFI noise but only with the ones in the master bedroom where my Sony 2010 portable is.  Noise is not too bad considering the distance.  

I noticed that sometimes I can flick the light switch off and back on real quick and the noise goes away even though the bulb is running.

Below is a photo of the p.c.b. from the base of a CFL.  I tore the assembly apart after the bulb became intermittant.  I think that I stressed the bulb due to swapping it around to many sockets and turning the bulb in and out by the tube.  Don't do this! Grip the CFL by the plastic base.

The p.c.b. has these parts:
1 PTC thermistor
1 inductor
1 transformer
6 film caps.
6 diodes
1 resistor
1 toroid
2 power transistors
1 22uf/200V aluminum electrolytic cap.

[AF9J]

Hi Tom,

The ones in my building, are not your typical coiled up CFLs.  I don't even think the base is compatible with a normal lamp socket.  I think it's a plug in type CFL.  Basically, they're configured like a trombone slide.  I've seen transformers next to the ones in the basement laundromat, that are installed bare (without housings around them).  I just took a look at GE's website. The bulbs in the CFLs in my building, are of the T4 or T5 type.  They're up and down the hallways of the 1st floor, 2nd floor, and basement, and used in outdoor lights that are basically located below my antenna.  Ugh!!

73,
Ellen - AF9J 

[KB2WIG]

"The ones in my building, are not your typical coiled up CFLs"

Some of the bigger lectrical 'users' run 277 volt lighting sys......  check out the base of one of the units and look for the majick '277'           klc

[Bill, KD0HG]

Those CFL bulbs *without* a screw-in base, with just pins on the end use either an electronic ballast or a passive inductive ballast, either type is part of the lamp housing itself. We have about 30-40 of the 9-watt CFLs in our offices. Passive magnetic ballasts would be too large and impractible for use in the screw-base CFLs.

I once took a look at the neutral to ground (building frame) noise in my office...Those switcher power supplies in all of our computers put *volts* of RF hash on the AC mains. I've had to use electrostatically shielded transformers in some of the studios to provide a truly balanced and more noise-free AC power source that's not referenced to ground. The ground prong on those outlets is isolated, going directly to the steel building frame, not back to the load centers.

[W2JBL]

     i first encountered those bulbs while on a "black ops" mission operating from a hotel room. the initial plan called for an indoor antenna taped to the ceiling of the room. the 30 over noise was so bad i could barely hear the "subject" and had to risk compromising the mission by damaging the window to get it open ("saftey" window, won't open), ripping away the fixed screen and running a wire outside the building. the bulbs made wicked noise on 75 and 40. there was a big type acceptance flap over those bulbs back in the 90's by the way. we put those things in where i work and a few days later i noticed the noise floor on 46MHZ was up around -70DBM and couldn't hear squat...so we went back to real bulbs. now we have Gore and the treehuggers trying to ban incandescent bulbs (like VK land) here... maybe we can convince them the RF "radiation" from compact flourescents is going to cause brain cancer, like shoe phones!

[AB1GX]

My experience is that standard FLs are much, much worse noise generators than the CFLs.  The newest CFLs I tried don't seem all that bad.

[WD8BIL]

Keep in mind that was CONDUCTED noise placed on the AC power lines.

I may get some time tomorrow to run some scans on the radiated electric and magnetic fields at 3 meters. We're setting up a temperary shielded room for some visiting engineers from one of our companies other facilities. They (being west coasters) were wondering why I didn't have any "green" light bulbs in the EMC labs !!! Geeezzz.... I guess they know why now !!

[WA3VJB]

Very interesting research Buddly, please post more as you continue. When CFLs first emerged from the laboratory there was significant concern they would be noise generators on HF. Manufacturers initially seemed to take that into consideration to help win market acceptance and FCC approval (in whatever order).

Today I wonder if anyone has one of those older CFLs with low hours to do a comparison run to the newest stuff.  As a cost-cutting move, I thought the QC might be allowed to slip among factories in the third-world countries making these things. The retail price has already dropped in half, and one wonders if its from more than economy-of-scale as production ramps up.

Ideally, I'd like to see high output, color corrected LED technology replace CFLs. It's amazing how much light they're already squeezing out of them things.  I put a 3W single LED bulb in my 3-D MagLite, and except for the bluish cast, there's lots of lumens pouring out of there.

Boy, the Hams in the days before electricity was invented were LUCKY

Yeah, I usually shut the AC Mains circuit breaker off when I get on the air. It really quiets things down.

[AF9J]

I have some spare time, before I leave for work, so I took a look at the CFLs in the hallway, and the basement of my apartment building.  The ones in the hallway seem to have an integral base, with the ballast circuitry in the base. The ones in the basement (one of which was listed as a Norelco PL9), are a bit more exposed (they're not in lamp housings).  They seem to have a step-up transformer feeding into the CFL assembly.  I'm not sure if the hallway ones are the same (they're a bit smaller, but it's possible that there is a transformer hidden in the lamp housing). 

I've always had problems with these things, but they've gotten worse over the past 3 months or so.  This seems to coincide with the time that they replaced the incandescents in the outdoor lights, with CFLs.  One of them is of the "lantern on a pole type that's very popular for outdoor lights.  It's located maybe 40 feet or so from my antenna, on a post in the back yard (which my apartment faces).  But, the kicker, is that I also have the noise during the daytime, so I don't know if it's:  A.) the timer for this light;  B.) The lamp housing isn't weather sealed too well (I've seen the ones by the entrances, and their weather sealing is a joke), and moisture is causing problems in the CFL circuitry, or the wiring;  C.) one of my neighbors now has a noisemaker in their apartment.

73,
Ellen - AF9J

[Ian VK3KRI]

The p.c.b. has these parts:
1 PTC thermistor
1 inductor
1 transformer
6 film caps.
6 diodes
1 resistor
1 toroid
2 power transistors
1 22uf/200V aluminum electrolytic cap.

So who's the first to build a transmitter out of a light bulb !

[WA1GFZ]

I shared the data with my EMI gang sounds like a science project is in our future. I didn't notice it was a CE scan....at least it will be lower as RE. I will not have any glow tubes in my house. I told the XYL we will buy a lifetime supply if some moron passes a law. Bud you might try snapping a bead on the power lead to see if it helps. Most outlet boxes are big enough to hold a bead on the leads to limit common mode CE on the power lines. It might be an easy fix. Bud see if you can measure the RE off the bulb without exposed power leads across the bench ground plane. Maybe copper tape them to the plane to see if the RE is off the power leads or the bulb. fc

[WD8BIL]

If I ignore the .8 meter rule Frank I can set the socket mounting plate right on the center access hole of the turntable and bury the leads below the GP. Looks like lunch will be fun today !

[WA1GFZ]

That sounds like a good test. fc

[K6JEK]

Had a chance to run some scans on the new bulbs of the future. This sample I have is a sylvania 23 watter (blue trace). The red trace is a 100W GE normal light bulb.

The lower limit line is the FCC Part 15 Class B limit for conducted noise.

I infer this is a CFL.   I think the bulbs of the future will be LEDs similar to this one http://movie.diginfo.tv/2007/03/07/index.php?ofs=0&pid=3   I've been informed by my neighbor who designs chips for bigger versions of LED fixtures that the ones he's working on have four (count em, 1,2,3,4) switching power supplies in a single fixture.   He told me what they were all for but I was too dumbfounded to listen.    They are getting 70 lumens/watt, nearly 10x incandescent, but the big draw is 50,000 hours expected life.   Do I have too many zeros?   Anyway, much more than anything else.   But four switching power supplies?  Oof.

[AF9J]

50,000 hours?  That's MY kind of light.  But, I didn't know they used switching power supplies for LED lights.  We all know that if switching power supplies are built & designed properly, they can be pretty quiet. BUT, if aren't built or designed properly, they can be extremely noisy.

73,
Ellen - AF9J

[W1VD]

Bud

If you have time...could you have a look in the VLF and LF range as well? I do LF stuff and those bulbs are particularly bad down there - conducted noise is the big problem. Sure hope the 'greenie weenies' can be stopped from banning incandescents.

Jay W1VD

[Tom WA3KLR]

The 60 Watt frosted bulbs I have on hand come out to 13.7 Lumens per Watt.
So 70 Lumens per Watt is a 5 X improvement.

The LEDs and the CFL are about 3 X more efficient than the incandescents.  The LED and CFL manufacturers usually say 4X though.