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DougS
10-04-2005, 10:27 PM
I'm using a Speakercraft MZC-66 AV distribution amplifier/controller to distribute video from a living room satellite reciever to a kitchen TV (wall mounted LCD display) and I'm getting lots of moving scan lines on the TV.

I'm using composite video from the Satellite Reciever to the Distribution Amplifier/Controller. Then composite video out from the Distribution Amplifier over RG6 coax to a wallplate in the AV cabinet, using a RCA-to-F-Connector. From there it's 50' of RG6 to the wiring panel. A female-female F-connector connects to another 50' cable run to the kitchen wallplate. With a final RG6 cable with F-Connector-to-RCA to the TV.

Is the problem that the run is too long and/or too many connections? Would a signal amplifier in the wiring panel help?

TIA
/Doug

AHEM
10-04-2005, 10:41 PM
If you haven't done so already, the first thing that I would check would be the integrity of the ground (shield) connection on all of the connectors and adaptors.

ejfiii
10-04-2005, 10:55 PM
After you check the grounds as AHEM suggests, I would get rid of the F to RCA adapters. You can get RCA compression ends for RG6.

Then, if AHEM and this doesn't fix it, then I would get a spool of RG6 and run a straight cable from the equipment to the back of the TV - no connectors, no adapters, just a long cable snaked through the house if you have to. If that is a nice clear picture, then its either the connectors, adapters, or a wire problem in the wall. Wire problem in the wall could be anything.

Good luck.

AHEM
10-04-2005, 11:22 PM
I've seen problems similar to this quite frequently when diagnosing CATV signal problems.

Electricians, do to cost and being lazy, love to use those horrid twist on F connectors, and with those things, if they strip off all of the braid, and unlike a compression or even crimp connection, all continuity to shield is lost, which results in the RG-6 acting like a gigantic antenna that indiscriminity passes signal and whatever noise it can pick up along the run.

I'd bet money that it's a connectivity issue.

sirroundsound
10-05-2005, 06:51 AM
Is the satellite signal being sent to other TV's, the same way?
If so how do they look?
What about taking the distro out of the picture, hook the satellite composite video to the RG6 that feeds this kitchen TV, any difference?
The main thing to do first is try to determine where the problem is, in the wires? from the distro? from the satellite reciever? then it will be easier to offer possible solutions.

DougS
10-05-2005, 09:31 AM
Thanks for the advice. I'll first check with a direct connection between sat and TV, then distribution amp and TV. If this clears up the problem I'll check/replace the connections.

Cheers,
/Doug

Gary
10-05-2005, 06:36 PM
If you have rolling bars, it is more than likely a ground loop and not a signal issue.

DougS
10-06-2005, 10:02 AM
Ahem,

I haven't been back out to the jobsite yet but if it is a ground loop problem what's the best way to deal with it?

/Doug

ejfiii
10-06-2005, 10:41 AM
I may have misread something, but the original post says that its a living room satellite receiver sending a composite signal out to a Kitchen TV.

I am assuming that there is a TV in the living room that also watches this satellite receiver using a different output? Is this true? Or does this satellite receiver only feed the kitchen TV and just happens to be located in the living room?

My point is that if its a ground loop issue (which we dont know since the original post isn't clear on what kind of problems he is actually seeing. "lots of moving scan lines on the TV" is not all that helpful) the ground loop would also show up on the living room TV. Provided its a coax ground loop type of problem and not an electrical ground loop problem of course.



I'm using composite video from the Satellite Reciever to the Distribution Amplifier/Controller. Then composite video out from the Distribution Amplifier over RG6 coax to a wallplate in the AV cabinet, using a RCA-to-F-Connector. From there it's 50' of RG6 to the wiring panel. A female-female F-connector connects to another 50' cable run to the kitchen wallplate. With a final RG6 cable with F-Connector-to-RCA to the TV.

I count 4 composite connectors, 6 F connectors and 3 RCA to F adapters in your single video run.

DougS
10-06-2005, 11:59 AM
I'm using component video out from the sat receiver (Directv HD10) to the Living Room TV through an AV Reciever, then a different output ,composite video, to the Speakercraft Distribution Amplifier and Controller, MZC-66. Then a composite video out from the MZC-66, which according to the specs is amplified.

Total connections from sat to TV
- Sat to MZC-66 (Composite 2 RCA)
- MZC-66 to LV Rm wallplate (Composite over RG6, 1 RCA/F, 1 F)
- LV Rm wallplate to wiring panel (Composite over RG6, 2 F)
- Fem-Fem adapter at wiring panel (2 F)
- Wiring Panel to kitchen wallplate (Composite over RG6, 2 F)
- kitchen wallplate to TV (Composite over RG6, 1 F, 1 F/RCA)

To be more specific about scan lines, the TV is a Vizio 20" LCD TV. The scan lines are most noticeable when there's no picture, only a black screen, in which case the scan lines are not uniform, i.e., a single line, but rather blocks of pixels across the screen, about an inch wide, and move from bottom to top.

TIA for advice
/D

Gary
10-06-2005, 12:41 PM
In my experience this kind of rolling bar is most often the result of the monitor being on a different electrical phase than the source component or switcher.

Try running an extension cord from the TV back to the head end, plug into the same outlet as the satellite receiver and see if the problem goes away.

AHEM
10-07-2005, 01:55 AM
Does this house per chance have CATV in it as well? Bad cable grounds often induce visual noise such as you describe.