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14-Mar-2017, 7:52 AM
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#1
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Junior Member
Join Date: Dec 2016
Posts: 21
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Picture affected by lite switch ...
Hey guys,
Just noticed something odd today. My tv picture pixilates badly when a certain lite switch in the house is turned on, I'm assuming this is being caused by interfering with the reception some how. The switch is "not" on the same circuit as the TV's power and is "not" on the same circuit as the signal booster's power. And, it's the only switch that does this. It reminds me of when I was a kid and the mixer in the kitchen would destroy the tv picture when running. The coax is new, dedicated run from antenna to tv. The coax is run separate from all romex in the attic. And, every lite in the is LED.
Any ideas?
Grassi.
Last edited by mikebuild; 14-Mar-2017 at 8:09 AM.
Reason: added info
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14-Mar-2017, 11:20 AM
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#2
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Antennas Direct Tech Supp
Join Date: Jan 2010
Posts: 2,942
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What you are experiencing is called a "switching transient" noise - Wiki article: https://en.wikipedia.org/wiki/Transient_(oscillation) . Most likely to affect VHF channels first but you didn't provide any details about WHICH channels were being affected.
The radiated electrical noise is being picked up by your antenna and just happens to overlap the affected channel(s) causing a loss of reception.
You cold try replacing the switch with a high-quality replacement and see if the issue was due to degraded internal contacts. While you're at it, check and see if the switch was properly grounded when it was installed.
Now, you made some sort of reference to LEDs in your last sentence fragment. LED light bulbs, especially inexpensive imports, have been implicated numerous times in cases of RFI, especially into VHF channels.
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14-Mar-2017, 12:59 PM
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#3
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Senior Member
Join Date: Dec 2009
Location: Delmar, NY
Posts: 1,236
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I think that one of the LED lights on that circuit is creating RF noise. I'd unscrew the bulbs one at a time until you find the culprit.
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14-Mar-2017, 1:57 PM
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#4
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Retired A/V Tech
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,747
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Quote:
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The switch is "not" on the same circuit as the TV's power and is "not" on the same circuit as the signal booster's power.....The coax is run separate from all romex in the attic.
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Interference can be radiated through the air or conducted through the power wiring, or both.
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And, every lite in the is LED.
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Every lite in the WHAT is LED?
If you have more than one LED lite, then unscrewing only one might not stop the interference.
Other people who have had this problem have had to try another brand of LED lite to solve the problem.
case history:
Having trouble receiving VHF signals.
http://forum.tvfool.com/showthread.php?t=16058
It was the dimmer AND the LED lights.
Last edited by rabbit73; 14-Mar-2017 at 2:10 PM.
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14-Mar-2017, 2:33 PM
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#5
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Senior Member
Join Date: Dec 2014
Posts: 341
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That switch or what it controls is bad and needs to be replaced.
Not just because it's creating interference, but the interference is telling you that you have a short of some kind. Could cause a fire one day.
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14-Mar-2017, 2:47 PM
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#6
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Antennas Direct Tech Supp
Join Date: Jan 2010
Posts: 2,942
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Quote:
Originally Posted by rickbb
....
Not just because it's creating interference, but the interference is telling you that you have a short of some kind. Could cause a fire one day.
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No, it probably means that the contact are noisy and the switch is failing. There is zero risk of fire but there is significant risk of a dark room when the lights eventually don't come on. There is no "short" of any kind, the term is misused due to a misunderstanding of what a "short" is. FWIW, the closed contacts of a switch comprise a "short" between switch contacts although an intentional one.
This, of course, assumes that the OP accurately described the symptom as a brief burst of interference when the switch is closed. I've seen numerous instances where this has been the case. My general expectation of the symptom, if it were the LED bulbs themselves, would be that the interference would be sustained beyond the initial switching interval. It's also possible that the problem is a poor connection of a bulb in its socket. A "dirty" or otherwise poor electrical connection at the bulb can cause that bulb or its socket to radiate electrical noise.
Ever notice how ambiguous descriptions of problems can lead to a spirited discussion of so many possibilities? 
Last edited by ADTech; 14-Mar-2017 at 2:51 PM.
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14-Mar-2017, 6:58 PM
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#7
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Retired A/V Tech
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,747
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Quote:
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Ever notice how ambiguous descriptions of problems can lead to a spirited discussion of so many possibilities?
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Yup, it happened here on this thread.
This indicates a possible transient OR continuous interference:
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My tv picture pixilates badly when a certain lite switch in the house is turned on,
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This indicates possible continuous interference:
Quote:
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It reminds me of when I was a kid and the mixer in the kitchen would destroy the tv picture when running.
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I went with the second choice.
Last edited by rabbit73; 14-Mar-2017 at 7:00 PM.
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14-Mar-2017, 7:54 PM
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#8
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Antennas Direct Tech Supp
Join Date: Jan 2010
Posts: 2,942
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I interpreted the symptom as a momentary transient.
Perhaps the OP will clarify.
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14-Mar-2017, 10:56 PM
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#10
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Moderator
Join Date: Oct 2010
Location: Greater Seattle Area
Posts: 4,773
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One thing is clear though... There are quite a few TV Fool members who desire to help.
It's appreciated.
__________________
If the well is dry and you don't see rain on the horizon, you'll need to dig the hole deeper. (If the antenna can't get the job done, an amp won't fix it.)
(Please direct account activation inquiries to 'admin')
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15-Mar-2017, 12:15 AM
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#11
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Junior Member
Join Date: Dec 2016
Posts: 21
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Thanks for the info guys ... current thread and prior.
The interference is constant with the light switch on.
All lights in the house (new construction) are LED. But that switch is the only one that causes interference.
My reception in general is very intermittent. A channel may be fine for quite awhile then suddenly pixelate, which makes it difficult to identify all channels effected by this noisy switch. But at this moment I can see that it is messing with 9 and 11 but not 13 (all three vhf , I believe).
I will look at switche(s) next (3 way light circuit) and check ground(s) as well.
Thanks again.
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15-Mar-2017, 1:10 AM
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#12
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Antennas Direct Tech Supp
Join Date: Jan 2010
Posts: 2,942
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Quote:
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The interference is constant with the light switch on.
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Thank you for that clarification as that was not discernible from your initial post. Clarity in describing symptoms is extremely helpful and is encouraged.
If it's continuous when the switch is on, then it's not the switch, it's the load (LED light bulbs) that the switch is controlling.
Unscrew one bulb at a time and see if you can pinpoint it, otherwise replace all the bulbs on that circuit with higher quality units.
Alternatively, see if you can increase the distance between the interfering lights and the receiving antenna by relocating the antenna (If feasible).
Last edited by ADTech; 15-Mar-2017 at 12:13 PM.
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15-Mar-2017, 8:19 PM
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#13
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Senior Member
Join Date: Dec 2014
Posts: 341
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