Noisy wiring for FM reception


Old 07-23-07, 11:06 AM
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Join Date: Apr 2006
Posts: 46
Noisy wiring for FM reception

Hi all.... I had gone thru several days,of posting back with the running wiring out to my shop,a few months back.... You did great,and the job came out great... Except for one problem..... After I got everything wired,and the power turned on,I find that I have an unexceptable noise problem at my workbench area,with my,FM radio reception...

The shop was built and wired as a package.... I then had to run power out to it,(220v)....That part went ok.... Afterwards I find that the way the shop is wired inside,is causing some terrible noise interference somehow..... I think I have it cornered,but I'm not sure as to which part is causing the noise...... I have two wall outlets at the work bench,and three more on the walls around the shop.I have a need at the work bench,to use one of the outlets as a power source for my radio... (hey gotta have them sounds while working)..... Ha Ha .....
Anyway,the radio is being powered with a Wal Wart 9v converter...The lighting is via two 8' flourescent fixtures.....If the lights are on,I'm getting so much static on FM that you can't even hear the station any longer.Turn the lights off,and alls fine with reception......

Hears some more wiring detail.... The two light fixtures are on the same leg of Romex that the two wall outlets at the work bench are on....That is they are on the same breaker... Also the lights are wired with a 3 way setup.... I have a lightswitch at both doors,wired via 3way.....
I have kinda figured that the noise problem is being created by the lighting 3 way system,or the fact that the lights are on the same Romex,as the wall outlets,that are powering my 9v Wal Wart.....I do know that the noise is not being caused by a Rf problem,via the antenna.I could see this being a factor on AM,but not FM..... I've never heard of FM Rf problems with Flourescent fixtures....Also the radio being powered by the 9v converter,inside my home works just fine.It's when I try to use this setup out in the shop....It's just no good.Theres a wiring problem causing this noise and I need to locate,and remedy,reguardless of means necessary.
However as I stated,I do think I remember reading somewhere that 3way wall switches,and dimmers, can cause a problem.....But the dimmers cause Rf antenna static..... My problem is based around noise entering via the wall outlet circuit..... Either because the lights being flourescent,and on the same breaker,wired thru the light switches then to the wall outlets.Or it's the three way switches by themselves,or both.....Any of ya have any ideas here...?? ......... Thanks you guys do a great service,and you know it !!!
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Old 07-23-07, 12:11 PM
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,399
Since your radio is powered by a wall-wart can you try running it on battery to see if the problem still exists?

The three-way switches should have no bearing on this problem but flourescent lighting is always suspect. Can you try the wall-wart in a receptacle from the other side of the line than the lighting is powered?
Old 07-23-07, 12:15 PM
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
Receptacles and lights on the same circuit is usually not a good idea, especially in remote locations where you might end up in the dark if you trip the breaker.

Fluorescent lights are notorious for putting noise on the circuit.

I would suggest trying a different circuit for the radio.
Old 07-23-07, 01:38 PM
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Join Date: Apr 2006
Posts: 46
More on noise findings

Hey...thanks Furd and racraft .....I just came back in to report a few findings.
Now ..... I'm back to my first thoughts,that it was a Rf disturbance emitted from the Fluorescent lights,and picked put via antenna.... I ran an extension cord from the house out to the shop,plugged in the radio,and it did the same when the lights were turned on.Sooo no shop power,nor connection, what so ever was going thru the radio via the power source.The noise was the same,with the lights on......
The shop isn't finished on the interior,so it would be simple enough to,just run a seperate leg of Romex for the wall outlets,and get them on a breaker by themselves,and off of the light wiring. I will just do that anyway,because I already wanted to add two more wall outlets anyway.After the comment about going in the dark........It was a good point...

Getting back to the problem at hand....As I stated,removing the radio power input from the shop wiring had no possitive effect at all.So that leaves me with it must be a received Rf disturbance emitted from the lights.
The only thing there,is that I've never known Fluorescent fixtures to have this effect on the FM band.
Just one thought .......and a buncha crap to have to do to find out.Is that maybe the lights have been shorted..... by that I mean a shortcut applied to the installation....... Such as not being connected correctly wiring wise..... The only thing I can think of in that area,would be a possible omission of ground somewhere.
I could actually remove one fixture from the ceiling,and check to see if the ground wire is attached...Although I don't know if that would make any differance with my particilar problem.
It's going to be really dissapointing,to install an enternal antenna,and find out that the noise is still there.

I even picked the radio up and walked around inside the building,with it connected via the extension cord,and it made no differance....
One more finding,and I'm done..... I did find out that the severe static being created,is only noticeable in a certain area of the FM band....when I go toward either end of the tuning range,the static falls off to not noticeable........
So again,that leads me to think,it's Rf related.Which was my first thoughts...along with implimenting an outdoor enternal antenna.......First I wanted to make sure I explorered the possibility of it being in the wiring though...
One more thing I can try,is to load the radio up with six D cells,and see what effect getting away from the AC current has,if any... Actually I hope there is no differance...... I fill at that point,I'd have it isolated to a near (no doubt) that the static was Rf in nature,and not caused by the wall outlets,and the present wiring arrangement...... I'll let ya know what I find using DC power,from batteries. I'm stumped as to how these lights can emit so much noise......... Thanks
Old 07-23-07, 01:50 PM
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
Try a different FM radio.
Old 07-23-07, 03:34 PM
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Join Date: Apr 2006
Posts: 46
Smile Last reply

Ya see ...... It just goes to show ya ..... If it aint Monday,it's Tuesday,it's always something.....If some people that come here and post,asking questions,like me ............. Would just do a bit of leg works (sorta speak),and check things out,maybe the time of the good pros here,could get more done........ I'm beating myself up a bit,but thats enough for now....... Hey .....thanks once again Furd and racraft ........ Problem sorce nailed.... We know it was the lights......of course.... I have verifyed that.

I went up in the attic,and gathered a length of 300 ohm TV antenna leadin,thats been laying around here for years....I grabbed it because the simple FM twin leg Dipole (put on the wall) antennas use this type material.

I went out to the radio and wired this (about 15 ft)to the antenna input on the radio,and just simply thru the end out the window,it was lieing on the ground.
I turned the radio on,went to the light switch turned the lights on,and sure enough there's the static as I assumed it would be....
I then went back to the radio,and at the point near where the external antena connects,it has a small switch thats for internal,or external antenna input.
I switched it to external,and Bingo,all the static noise was gone.... This is with the radio power connected via the 9v WalWart.
It seems in fact ...... that the static was indeed Rf received,as it was being generated from the Fluorescent lights.However,all isn't completely solved,but the rest is simply,a need for a few pieces of additional hardware.
I can't use this antenna for AM,but the lights don't seem to be bothering the AM reception.So I'll have to flip the internal / external switch as necessary depending on the desired band,and antenna input.....
I live about 35 miles from the FM station of my listening,and needed a good external antenna anyway.... Just more the reason that I install one now............
Not to mention,that I was really pleased,with the lighting that was installed,and didn't even care for the idea of maybe having to go another lighting route.
I do (as I see it) have an advantage with this problem due to this particular radio.This is based solely to the fact that the radio I'm using has the ability to completely disconnect the internal whip antenna,via the mentioned switch,and that in itself helped to null the Rf input,from the Fluorescent lighting static.... Otherwise you'd still have the Rf input effect from the lighting even with the use of an external antenna.
Or,thats my 2 cents worth.
Maybe,for the readers(if any)that would have been in doubt,as I was.
Now we know.
Hey another crisis solved........ Thank you both.......

I also want to mention this here.Thank you both again,for the wiring help,on the other problem Question that I had earlier,a few months ago.
I just today left my input from the help you offered then... It was the question about installing a sub panel,and running 220v out to the shop...... Thanks to you all......... Another happy camper ........
Old 07-23-07, 03:43 PM
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Join Date: Apr 2006
Posts: 46
Smile One more comment

I do fill a need to say..... that although I have seemingly found a way around my static problem....... I have no idea why it was so bad out in the shop..
My point.......I still do not know if there is/was something done handled improperly with the wiring,that caused this problem......
I will point out,that I have Fluorescent lighting in my house,and it dose not cause this problem .....
Knowing me though,I'll never know.......Due to removing,and checking light fixtures is the only way of knowing for sure.......
I can at this point,live with it the way it is..........
Old 07-23-07, 05:07 PM
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Are the lights properly grounded?
Old 07-24-07, 11:02 PM
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Join Date: Apr 2006
Posts: 46
Smile Checking ground ?

Ray 2047 ..... My answer is "I do not know" .......
That was part of my last words......... I mentioned that I still didn't know why so much noise was being caused by those Fluroescent overhead lights....
I have had the chance to have removed,and reinstalled several of the wall switches,that the building builder installed.....
I found no improper wiring anywhere,that would be considered a shortcut,to the installation.All switches,were properly grounded....... However,I have not removed the ceiling fixtures,to check the wiring connections....
Primarily due to the fact that I lack the experience,to be knowledgeable enough to know what I was looking at....

I'm not a trained Electrician........ I would be able (of course) to notice if the ground wire wasn't even attached to the fixture,but that would be the extent of my checking........ I do not know right from wrong,as to grounding the light fixture.
Sence I didn't install them,I do not even have the benefit of inclosed instructions,that usually accompnany the purchase.

I do suppose,I could at least drop the fixtures from the ceiling,and check to see if the ground wire is attached........ I don't have any reason to figure it wouldn't be..... Other than the fact that these lights are really causing havoc with my FM reception.....

If the static was being perceived as to coming from the wiring,via the wall outlet.....I surely would be pursuing the ground,idea...
If that were the case though.The static wouldn't have been removed by switching to an outside antenna..... Or thats my thoughts.

Again though setting up an outside antenna,seems to have cleared up the static,indicating that it was indeed an Rf airborn frequency disturbance,picked up via the whip antenna,that I was dealing with......

Is it possible,that the Rf disturbance,was created by a faulty ground at the fixture? ........ Good question ....... I do not know if thats possible,or not.
I can see that it's reasonable,to think that it could be...... I suppose that the Fluorescent function,is due to or related to a rapid firing cycle,and it's possible that this could create some atmospheric disturbance,if there was a grounding need,and it wsn't in place.
I do not have a solid familiararity with the Fluorescent workings.
Old 07-25-07, 09:18 AM
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It's a pretty solid rule that you get what you pay for with fluorescent lights; the builder probably put in the cheapest fixtures he could find for a garage/shop type building. Cheap fixtures have noisy ballasts which flicker, audibly hum and pump out EMF noise like crazy even in the RF bands. More expensive fixtures (ballasts) are audibly silent and have EMF suppression.

Yes, a bad ground in either case would cause the fixture to be noisier than usual.
Old 07-25-07, 03:39 PM
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Join Date: Apr 2006
Posts: 46

ibpooks .........thanks for your input....... I had assumed,that there may be a differance in quality,between different fixtures of this type....
I wasn't sure about,just what the different quality points could do to this type of problem,or what influence the quality could have on the Rf disturbance effect......
Also yes..... I would also assume the builder,has provided the lowest cost applied specs......
I do know that the builder has stopped,maintaining a permanant on site electrican....The electrical build/install,is now shopped out,but to usually only one or two people..... Actually I guess,to whichever one takes the job,for what ever the percentage.....maybe..... I'm not sure about how the electrician gets paid.
I do know that all electrical componants.....all....including the wire,(Romex) boxes,everything,is provided by the electrican....... So from one building to another.....who knows what standards there are..... if any.

I'm reasonably sure that code is maintained,but the work,and or quality,probably is not a cared for standard.....

At this point I'm not going to entertain,the idea of changing out fixtures.
They will always be accessable,if in the future I find I can use the fixtures, an area where I want care about this problem,I may very well swap them out for whatever I can find that may be a better choice..........
I needed some word mentioned as to the area of performance of this Rf matter.....Concerning the Fluorescent lighting,and it's ability to cause this kind of disturbance.. I will follow your input as mentioned and do some shopping around for the particulars mentioned.

You know.....some I mentioned way earlier.....that use Fluorescent lighting,are faced with this area of build concerned....... from hospitals ....... to electronic works...... I'm also aware of the need for proper connections that help to eliminate Rf leakage,from entering into the reception....Most of this being closed circuit connections.
Trying to maintain a quiet Rf signal via an open air antenna,could be a real challenge....

As you mentioned though,I'll check for standards applied from different manufactures,based around this area of concern.....and see what I can find.
If this matter of Rf disturbance,created from leakage within the Fluorescent
lighting industry,is a matter that has been dealt with,and there are particular fixtures that handle this well........
I do not know if I want to afford,the costs....... I will pursue this issue though.
Thanks again........
Old 07-25-07, 04:08 PM
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For the most part the interference is reduced or eliminated with high quality fluorescent ballasts. Also in the types of commercial buildings you listed like hospitals and office buildings, lighting is isolated on a separate 277V transformer from the 120V receptacles, and wiring is run in metal conduit which dampens some of the interference.

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