Sis lives upstairs. Mom lives downstairs. Sis just completed some home improvements that inlcuded installing a new flourescent light fixture in her kitchen. When she turns it on, mom’s rabbit-ear TV, located in the kitchen below, gets all staticy.
What’s going on here and how can I cure it?
Is the interference coming through the house’s power lines? If so, there is a gizmo that Radio Shack sells for about $12, that looks like a glorified extension cord (there’s an oversized female recepticle at one end) that claims to filter out “interference from appliances.” Would this solve the problem?
Or is it broadcast “noise”? In which case, can I shield the light fixture or the TV, or install some other kind of filter (from Radio Shack maybe?) ?
Maybe it’s a “solid state” ballast in the lamp. These put out high frequency electrical interference. It’s supposed to be very low level, but it might be enough to interfere when your TV is tuned to a distant station (or if you’re using a very bad arial.)
Either try grounding the metal part of the fixture (and make certain the ground wire actually goes to an earth stake or a cold water pipe.) That, or tear out the ballast entirely and replace it with one of the older iron-inductor ballasts.
Check to see if the light and tv are on the same circit.If so, try plugging the tv into a different outlet that is not on the same circuit as the light
I’m not an electrician. However, if I had installed the fixture myself, I’d go back and see if the ground connection had gone wrong. Once I had a connection pop loose as I was wrestling the stiff wires back into the junction box.
Make sure you have grounded the fixture.
To check for ground -
Turn off the circuit (or switch to light).
Take an ohm reading from the nuetral (the white wire) to the ground wire or the electrical box the wires come out of (if the box is metal it should be grounded).
You should get 0 ohms (a dead short) between the nuetral and the ground wire or the box. This indicates that you have a ground.
Make sure the fixture is physically connected to the ground wire or jumpered to the grounded box. There is a ground screw (green in color) or a green pigtail on the fixture that you should use for the connection of the ground wire.
Move the rabbit ears. Unless they are the ones that came with the TV. Then buy portable ones.Use coax
or
Put up a cheap outdoor antenna.use coax
or
Hook up to sis’s antenna.use coax
or
Try one of those TV antennas that use the house wiring.
It’s not RF interference, it’s electrical interference.
Picture an office with a dropped ceiling and flourescent lights. Picture a cheap office manager who puts unshielded cat five above the lights in the dropped celing instead of some place else (or doesn’t sheild it in any way).
Result: erratic network, dropped packets, total unreliability.
As others have mentioned, the lamp is probably emitting a bunch of high frequency garbage. The unknown, of course, is what path the interference is taking. It is likely one of the following:
a) The lamp is emitting RF noise via EM waves. There are three potential solutions to this problem:
Ground the fixture and/or electronic ballast (if not already grounded)
Stick a filter between the rabbit ears and TV
Buy a better lamp
b) The lamp is injecting noise via the home’s AC electrical system. Two potential solutions:
Plug the TV into an AC line filter
Buy a better lamp
So how do you know which path the noise is taking? To answer this, you’ll need to do some experimenting… Does the noise occur on VHF and UHF? Does the noise occur when a VCR is used with the TV’s “video in” jack?
I meant only that the light was not built to transmit TV signals, though it may be causing the interference.
Generally, I was speaking that you can’t test every item in every situation for non-interference … someone was talking about FCC regulations up there.
And an identical-sounding light fixture (flourecscent) was causing interference in the noted example of unshielded cat five cables running over/near flourescent lights above.
You can call it “RF” interference ifyou want … I declined to merely because the lights aren’t built to transmit on RF and aren’t held to the standards.
And it’s not necessarily a “lamp” that can be ripped out and replaced. In my kitchen, it’s a full flourescent fixture that is embedded in the ceiling; wouldn’t be a matter of changing out a simple lamp.
