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TV Interference - Fluorescent Lighting

T

TKM

Jan 1, 1970
0
Anyone have some suggestions about reducing TV interference from fluorescent
lighting in a residential situation?

The house, which is new, has numerous T8 and CFL lamps -- all electronically
ballasted; but it's only the undercabinet lights in the kitchen and laundry
area that cause the interference. These are F25T8. The fixtures are
properly grounded and the ballasts have the proper FCC marking; but the
pictures on the TVs in the house go nuts when the lamps are on. The house
doesn't have a cable TV system, just antennas on the sets.

Terry McGowan
 
D

Don Klipstein

Jan 1, 1970
0
Anyone have some suggestions about reducing TV interference from fluorescent
lighting in a residential situation?

The house, which is new, has numerous T8 and CFL lamps -- all electronically
ballasted; but it's only the undercabinet lights in the kitchen and laundry
area that cause the interference. These are F25T8. The fixtures are
properly grounded and the ballasts have the proper FCC marking; but the
pictures on the TVs in the house go nuts when the lamps are on. The house
doesn't have a cable TV system, just antennas on the sets.

Terry McGowan

If that happened to me, I would try a different ballast, preferably of a
brand known to serve me well. I would suspect that the cranky ballasts
are defective (RFI supression broken or not properly installed) or have
fraudulent use of the FCC marking.
After that, I would check to see if the safety ground is taking a
different path from the neutral outside the fixture (and get the household
wiring "more normal" if this is not the case). I would also bunch the
line leads and the fixture ground lead together, and have outgoing and
return leads for each lamp close together. Reducing "loop area" of a
current path sometimes reduces RF interference transmission.

I would also post what actually achieves the fix.

- Don Klipstein ([email protected])
 
V

Victor Roberts

Jan 1, 1970
0
Anyone have some suggestions about reducing TV interference from fluorescent
lighting in a residential situation?

The house, which is new, has numerous T8 and CFL lamps -- all electronically
ballasted; but it's only the undercabinet lights in the kitchen and laundry
area that cause the interference. These are F25T8. The fixtures are
properly grounded and the ballasts have the proper FCC marking; but the
pictures on the TVs in the house go nuts when the lamps are on. The house
doesn't have a cable TV system, just antennas on the sets.


FCC regs are not strict enough to prevent interference with
radio and TV receivers in the same house as the offending
device. We discovered this when we were designing the early
electrodeless fluorescent lamps. A ballast for use in a
residential environment should be designed to tighter limits
than required by the FCC.

I would take a look at the ballasts used with the T8 lamps
that do not cause interference and then those with the F25T8
lamps that do. If they are different brands or models, then
switch the ballasts from the F25T8 systems to the better
brand.

--
Vic Roberts
http://www.RobertsResearchInc.com
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TKM said:
The fixtures are properly grounded and the ballasts have the proper
FCC marking;

IMHO, in these latter days, all this means is that the manufacturer is
competent enough to operate a screen printing machine, or to hire
someone who can. I have disassembled PC power supplies that had all the
relevant markings but that were suspiciously light for the claimed
output power; usually the circuit board has the solder pads and silk
screen for components like the line filter chokes and capacitors, but
only a jumper wire (choke) or nothing (cap) is actually installed. So
I echo the recommendation to switch to a known-good (or at least
different) brand of ballast.

If this does fix it, and if you have more than one faulty ballast, it
might be interesting to open up one of the faulty ballasts (if possible)
to have a look. If it's scary, you might take it up with the relevant
safety agencies - this may or may not help but at least you can try.
Posting photographs on the Web, and telling everyone you know in the
lighting business that those ballasts suck, may be just as effective.

Matt Roberds
 
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