T8 fluorescent fixture and FM radio signal

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Forum topic by TurnTurnTurn posted 12-19-2012 02:57 AM 4468 views 0 times favorited 17 replies Add to Favorites Watch
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613 posts in 3109 days

12-19-2012 02:57 AM

Topic tags/keywords: question

HELP!!! Up to now all of my shop lighting is provided by t40 fluorescent fixtures that included a cord and plug. I had to replace one of the fixture and bought a T8 direct wire fixture. Since I wanted to plug it in I simply added 2 wires and a plug. The light works fine, but I cannot put my FM radio within about 5-6 feet of this light because it will not get any reception. If I set the radio near the light the radio gets no signal until I unplug the light fixture and then the FM signal returns so I know it has something to do with this light. Any thoughts or suggestions to fix this issue? Thanks

-- TurnTurnTurn

17 replies so far

View Gary's profile


9331 posts in 3433 days

#1 posted 12-19-2012 02:59 AM

Had the same problem. Had to add the extra ground wire, then the radio worked

-- Gary, DeKalb Texas only 4 miles from the mill

View JoeinGa's profile


7736 posts in 2007 days

#2 posted 12-19-2012 03:00 AM

If you like (or need) the light where it is, find another place for the radio. Like across the shop maybe? That’s what I did when I encountered the same issue.

-- Perform A Random Act Of Kindness Today ... Pay It Forward

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613 posts in 3109 days

#3 posted 12-19-2012 03:01 AM

Thanks Gary, I will give that a try.

-- TurnTurnTurn

View hhhopks's profile


651 posts in 2377 days

#4 posted 12-19-2012 03:43 AM

That is interesting. I am not aware of this. What make and model is it?
Most likely it is the ballast of the fixture (like a transformer) that interfers with the radio signal.
EMI (lelectromagnetic interference) perhaps. I would think the fixture are suppose to meet certain EMI standard.

Folks with electronic device on their body for heath reasons (like a pacemaker) need to be concern about these things.

-- I'll be a woodworker when I grow up. HHHOPKS

View TopamaxSurvivor's profile


18271 posts in 3676 days

#5 posted 12-19-2012 04:42 AM

All these electronic ballasts and other electronic devices do strange things to electrical systems and equipment.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View redryder's profile


2393 posts in 3102 days

#6 posted 12-19-2012 06:26 AM

Go to satellite radio like I did. That FM radio will be in your next garage sale. You’ll never look back…...............

-- mike...............

View kizerpea's profile


774 posts in 2367 days

#7 posted 12-19-2012 01:20 PM

make a home made antenna an mount outside shop…i did an got alot more stations ..i bought a tunner with remote an speakers $40 from a yard sale now it rocks da shop!!!!google how to build a fm antenna..


View dhazelton's profile


2767 posts in 2297 days

#8 posted 12-19-2012 01:37 PM

An old set of TV rabbit ears or a small rooftop VHF antenna is a good radio antenna (the FM spectrum resides on VHF channel 6). Satellite radio isn’t for everyone and 15-16 bucks a month is hard to swallow when local radio is free.

View Sarit's profile


549 posts in 3140 days

#9 posted 12-19-2012 05:30 PM

The electronic ballast in these lights that are rated for commercial duty, often don’t have enough RFI shielding. Its best to get ones rated for residential applications. If you call the manufacturer of your ballast they will sometimes replace yours for another one that may work or at least recommend which version to use.

View Sarit's profile


549 posts in 3140 days

#10 posted 12-19-2012 05:40 PM

FYI, these are the lights I’m planning on getting once my garage remodel is done:

View teejk's profile


1215 posts in 2684 days

#11 posted 12-19-2012 06:54 PM

I have a steel building so I never got to see the impact of the lights since I already had issues. I had to take a wire outside the building. it is only cheap speaker wire (small hole) that I split to form a T and unless the deer knock it down, it works.

AM actually works better with the lights although there I have problems with cordless tool chargers (“click, click. click”).

View Tennessee's profile


2873 posts in 2514 days

#12 posted 12-19-2012 07:13 PM

Sarit, yours come rated with the residential ballast, you should be OK. TTT, adding the ground wire should eliminate most of the RF. Cheap ballast T8 units set up a magnetic field that acts as a shield for certain wavelengths of the radio spectrum. I’ve had the same problem setting up guitars – the pickups go nuts under certain types of cheap lights. I’d ground the light and later on, buy residential rated ones. Should say right on the box. I don’t think there is any reason to worry about pacemakers, otherwise every person with a pacemaker would be in trouble every time they walked into a building with a commercial flourescent fixture. Microwave band is much, much higher on the spectrum.

-- Tsunami Guitars and Custom Woodworking, Cleveland, TN

View teejk's profile


1215 posts in 2684 days

#13 posted 12-19-2012 07:47 PM

tennessee…I think all the T-8 fixtures are grounded since they use electronic “ballasts” (I heard that the primary reason for premature failure/warranty claims is because of poor ground).

T-12’s are soon to be dino’s (I think they got extensions on the US mandate until mid 2014) people transition to the new stuff, the issue will certainly get more focus. Until then, get a cheap antenna outside.

View crank49's profile


4030 posts in 2971 days

#14 posted 12-19-2012 08:18 PM

I’d be looking at T-5 bulbs and fixtures if I were you guys.

FYI the T# refers to the diameter of the tube. T-12 = 1 1/4” diameter, T-8 = 1” diameter, T-5 = 5/8” diameter.

After LEDs, which are very pricey, the next best product out there is the T-5 HO which stands for Hi Output. A nominal 48” long T-5 HO tube uses about 54 watts and produces more than twice the lumen output of a T-8 32watt tube. Also, they are electronically controlled so they can cycle on and off without degrading. Life expectancy is much greater. In industrial installations we install thousands of these T-5 lights to replace metal halide and similar fixtures.

View teejk's profile


1215 posts in 2684 days

#15 posted 12-19-2012 08:31 PM

thanks for that crank…not sure I’ve seen them in the big box stores yet but the concept is appealing. I have 2 banks of T8’s on my ceiling (bright white steel) and they are more than enough for general lighting (the bright white helps alot there and I would recommend that anybody doing a shop pay attention to that). But I do plan on adding task lighting over benches (if I ever get them cleaned off) and those T-5’s sound like the ticket.

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