help with eliminating Interferences (Video Noise) using S-Video

[F07]

Hi everyone.
first of all, I've got to say that I've been following this website for over 5 years now and I think it is one of the best, most thorough and professional sites I have encountered.

I need some help with Video Noise that I always get when using analog cables such as composite and s-video.
I have a basic tv-card: Leadtek Winfast TV2000XP RM
I use ChrisTV Pro for viewing and capturing using MPEG software encoding.

I Connect my tv-card using a cable set-top box (STB) of my cable company. the cable company uses a set-top box of ADB, model 7200C.
I'm using a Phillips SCART to S-Video cable, model: SWV3612W/10, to connect the tv-card with the STB.

any TV Program I watch, I get these annoying Interfereces, which manifests themselves as best describable as "Waves".
Since I need to compress the Recordings using XviD Codec, these interferences cause the compressed file to be ugly, even though they are not visible at all times if you watch the original MPEG2 files.

the Interfereces are best viewable when there is motion and when the background is dark. like if a person wears a dark blue t-shirt you can see that it is not so smooth as it should be without the noise that is added.

if I posted a still image, the noise won't be so visible, cause it is best viewed when in motion. :\

so, bottom line is:
what is causing these Interfereces and how can I get rid of them? :\

please, anyone who can tell me what to do except buying another tv-card, will be much appreciated.

thank you so much in advance.

[edDV]

A picture cap would help. Are you capturing to 576i or 576p or?

Is this standard interlace?
Is this PAL cross colour/cross luma?
Is this deinterlace artifacting?

[F07]

Thanks for your reply...

hmm, as I said, I can post a picture of a capture, but the noise won't be visible as it is only visible in motion.

about Interlace/Progressive:
As I said above, I capture using ChrisTV and the program captures the content as interlaced, so no matter if the content is 576i or 576p, the interferences are always there. Even when I switch channels and the picture freezes for a second or 2 when it changes channels, there are waves.
so the problem is not on the recorded file. it is visible while watching live.

I can describe the problem, when in motion, as waves and even "smoke" (:O)...it's always passing to the right...

People told me that these interferences are called Radio Freqeuncy and it is caused because the PC and any other electronic equipment are emitting high frequencies which cause this effect (or "noise").

I know that it is not caused by interlacing or deinterlacing or any other post-processing effects\filters.

I bought a scart-to-svideo cable just for the elimination of this noise, cause every person I asked, told me that an expensive and gold plated cable will do the trick.

i'm so frustrated about this. never in my 3 years of analog tv-card experience I managed to get a clear picture. :\

if you or anyone else have any other ideas, I will gladly appreciated it...

Thank you so much.