[mythtv-users] TV-out problems

[Matthew Schumacher]

Rick,

That is some good advice.  The only thing I would add is that electrical 
cables in the wall can also broadcast a lot of noise.  I used to have my 
monitor next to a particular wall in my old house and it had lines and 
such, but then when I moved to my new house it went away.  So if you 
turn everything off and still have problems then try setting it up on 
the kitchen table.

schu

Richard Lee-Morlang wrote:
> On Tue, 2003-04-22 at 13:35, Dave Weaver wrote:
> 
>>However this is all somewhat spoiled by a horizontal sweeping flicker -
>>about 3 'sweeps' per second. It's a bit like what you see when you see
>>computer monitors on TV, except it's a vertical lines moving in a
>>horizontal sweeping motion.
> 
> 
> I had similar problems but with horizontal lines moving in a vertical
> direction.
> 
>>From the research I did, it seems this is referred to as banding (at
> least in my case), and is caused by noise picked up by your cables. In
> my case, there were four primary sources of noise:
> 
> 1) a hub I had sitting near the rest of my equipment - when turned on,
> it severely interfered with the cable TV signal. The kind of
> interference varied depending on the channel. Solution: get rid of the
> hub.
> 2) if you have a cable tv signal or tv antenna plugged directly into
> your TV, the ground on that connection can interact with the ground on
> the cable connected to your computer, and cause noise in the image.
> Solution: unplug the cable from the tv, since I'm using myth to tune
> channels now anyway
> 3) I had a splitter on my cable connection so I could connect both my
> vcr and my myth box to the cable signal. When I connected the myth box
> directly, bypassing the splitter, the picture improved significantly.
> 4) I had bought a new NVidia Ti4200 card for my myth box. While trying
> to solve my noise problems, I noticed a small improvement in signal and
> picture quality when I tried my old NVidia MX440 card.
> 
> I also managed to add a lot of noise by trying out a different S-Video
> cable.
> 
> I would suggest:
> 1) turn off every electric device you can, hopefully leaving just your
> TV and computer running. If that improves the signal quality, turn
> devices back on, one by one, to see which ones contribute to noise
> 2) eliminate as many device interconnections on your computer and TV as
> possible. Start with only the power cords, and the video connection to
> the TV. Then gradually add more connections, starting with the cable
> signal to your tuner card. Take note of how each added connection
> affects the picture quality.
> 3) avoid running any cables near any of your device power supplies as
> much as possible
> 
> If you can narrow down where the noise is coming from by trial and error
> and process of elimination, you might find that all you need to do is go
> out and by a cable with better shielding to solve your problems. 
> 
> Rick
> 
> 
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