interference over cat 5 wiring

Thread Starter

domino101

Joined Dec 20, 2013
14
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
 

#12

Joined Nov 30, 2010
18,224
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.
 

crutschow

Joined Mar 14, 2008
34,285
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.
 

#12

Joined Nov 30, 2010
18,224
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!
 
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)
 

Thread Starter

domino101

Joined Dec 20, 2013
14
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
 

#12

Joined Nov 30, 2010
18,224
Did the different sources come from someplace that does not include your circuit breaker box for the house?
 

Thread Starter

domino101

Joined Dec 20, 2013
14
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:
 

Thread Starter

domino101

Joined Dec 20, 2013
14
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.
 

inwo

Joined Nov 7, 2013
2,419
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.
 

Thread Starter

domino101

Joined Dec 20, 2013
14
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
 
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