interference over cat 5 wiring

Discussion in 'General Electronics Chat' started by domino101, Dec 20, 2013.

  1. domino101

    Thread Starter New Member

    Dec 20, 2013
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    new to forum, could use some advise.

    my house has cat 5 wiring for hdmi video from a sat receivers to my tv sets. everything works good, but it get a video 'flicker' when turning on a ceiling fan, the furnace turns on, or certain electrical items are plugged in to a third household circuit. 3 circuits cause this issue, i have tried the obvious, relocating electrical cables to about a foot away, but same problem. the only thing left is that the 3 circuits causing the issues run parallel within inches of the main support steel i beam. can emi be strong enough to be inducted into the i beam? would that be amplified enough to case 'flickering'? if so, can simple grounding of the beam fix this?

    thanks
     
  2. #12

    Expert

    Nov 30, 2010
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    More likely the flicker is caused by noise on the power line, not pickup by the cat 5 cable.

    I have the same problem at my house and find it impossible to keep the power line so clean that a TV will not flicker when I change speeds on the ceiling fan, and I don't have any cat5 wire in the house except a 12 foot wire from the dsl modem to the wireless router.
     
  3. domino101

    Thread Starter New Member

    Dec 20, 2013
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    if true, what would resolve the issue?
     
  4. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Bigger caps on the TV power supply.
     
  5. crutschow

    Expert

    Mar 14, 2008
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    Can you pick up any over-the-air signals? If so you might try running the TV with that to see if you still have the problem. If you do than one solution might be to use a UPS to power the TV.
     
  6. #12

    Expert

    Nov 30, 2010
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    Since I have not defeated the problem, I can't say for sure. Some kind of filtering on the plug of the TV, but the interference will still be in the circuit breaker box and therefore can get to the satellite amplifier.

    Personally, I gave up and quit demanding that the TV never flicker, and I was a TV repairman for several years!
     
  7. dmshropshire

    Member

    Dec 1, 2013
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    Shooting into the dark here... Can you tell if its a power fluctuation on the TV or is it the video signal dropping out? Is there any further distortion in the picture after it happens? (no matter how small)
     
  8. #12

    Expert

    Nov 30, 2010
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    That's what crutschow was working on in post #5...how to tell the difference.
     
  9. domino101

    Thread Starter New Member

    Dec 20, 2013
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    More info here

    This happens on 2 different tvs on 2 independent circuits . both have cat 5 wiring to supply hdmi video. it really appears not to be a power related issue as i have independently supplied power from different sources with the same effect. it really appears to be just a momentary loss of signal
     
  10. #12

    Expert

    Nov 30, 2010
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    Did the different sources come from someplace that does not include your circuit breaker box for the house?
     
    inwo likes this.
  11. domino101

    Thread Starter New Member

    Dec 20, 2013
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    power supplied was from a different source from within the breaker panel.

    more info on the set up i have

    the cat 5 wiring runs from a remote closet where all video equipment is located. it then spreads out through the house as needed. along with the cat 5 wiring is also some coax and speaker wire...not currently used but available for a home theater system.. the wiring is open through the ceiling of the basement, and only disappears into the wall located under the 2 tvs that are being supplied. that in wall portion is only a vertical run about 3 feet long and unaccessible. it runs parallel to power wires which i thought was the problem, so i moved those approximatly 12 inches away with no help. it also runs across a metal return air duct still in parallel with the power wires, then makes a left turn across a metal i beam. i did run a ground wire from the return air duct. nothing i have done has helped, thats why i suspect the i beam causing issues.:confused::confused::confused:
     
  12. domino101

    Thread Starter New Member

    Dec 20, 2013
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    one other note...i had an hdmi cable from a different location supplying video for these tvs...never an issue.
     
  13. crutschow

    Expert

    Mar 14, 2008
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    Is that cable also connected to the satellite receiver?
     
  14. domino101

    Thread Starter New Member

    Dec 20, 2013
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    it was until i switched to the cat5 wires

    i would continue to use the hdmi cable, but we paid a lot of money to have the house wired for cat 5....plus it allows all the equipment to be located remotely. with the hdmi cable, the equipment was located near the tv.
     
  15. inwo

    Well-Known Member

    Nov 7, 2013
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    Are you using "HDMI over cat 5" devices?
    Many different types.
    Most use two shielded cat5e or cat 6. Some squeak by with one.
    I believe some are just passive baluns, without enough gain to be above the noise.

    If it is a cat5 fed satellite receiver, your provider should have answers.
    I was a DN retailer until end of last year. At that time cat5 feed to recievers worked but was not approved.

    Are cables shielded? Very important for long runs.
     
  16. domino101

    Thread Starter New Member

    Dec 20, 2013
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    the receivers are direct tv with coax input. the outputs are hdmi. yes, i do use the hdmi extenders, which convert hdmi to cat 5, then back to hdmi on the other end...then hdmi to the tv. there is a 12 volt transformer that plugs into the wall that powers these units. these units use 2 cat 5 cables that run between the ends.

    i am confident that these hdmi extenders are not the issue. i had a set of these in the past that also were flickering, and thats why i purchased new ones....which do the same. another t/s item i did was to plug in the 12 volt power supply to another source with no change.

    the cat 5 is unshielded...i wonder if it was, maybe i wouldnt be having issues. and the cat 5 run is only about 60 feet. hdmi cables are 2 feet each
     
  17. inwo

    Well-Known Member

    Nov 7, 2013
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    The specs I've read say that shielded cable is required over 100'.

    As you are less than that.:confused: Maybe?
     
  18. inwo

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    Nov 7, 2013
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  19. domino101

    Thread Starter New Member

    Dec 20, 2013
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    yes...about 60 feet
     
  20. domino101

    Thread Starter New Member

    Dec 20, 2013
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