Problems Capturing from Cable with ADVC-100

[TheUglyDuckling]

Recently, I split my cable (television) line in order to be able to digitally cap the signal with my ADVC-100. I lead the new RF cable into the back of the Sony VCR which is located next to my computer, and the signal goes out through the composite video out jacks and into the ADVC-100, just like it would when I am backing up VHS tapes.

Everything seemed to work (at first glance), but it became readily apparent that the incoming signal had a great amount of interference -- a low hum was present in the audio, and the video waved slightly. This surprised me, since I'd used a shielded RF cable, but it did not seem to be a completely unreasonable to assume that the cable line was picking up interference from other cables.

Now, if the problem was as simple as my cable line picking up interference from the power cables under my desk, I would not be confused. However, now that I've connected the cable signal to the back of my VCR, the signal from VHS playback (which was fine before, and shouldn't be dependent on the cable signal) is affected by the same interference. Am I wrong in thinking that this shouldn't be happening, since the VHS playback should not be affected by interference from the incoming cable signal?

Has anyone experienced a similar problem, or does anybody have any idea how to fix it? Might a different VCR resolve these issues?

Thanks in advance,
TheUglyDuckling

[redwudz]

Try unplugging the cable from the VCR and see if the VHS output still has the interference. I am assuming you have plugged the VHS player into a TV to rule out the computer as the interference source.

What it sounds like is a grounding problem, either with your cable or your VHS player. Try plugging the VHS player into a different outlet. If no changes, try a different VHS player. It may have a internal loose connection.

If all your outlets are three wire (With the ground lug), you shouldn't have these problems unless there is a loose connection or bad cable somewhere.

[pluche]

apart from a potential "grounding problem" as already mentionned, such problems can also be caused by the cable signal splitter; it had that once, I removed the splitter and problems were gone;
what I use now is a kind of splitter/amplifier : one RF entrance (attached to the cable line) and 6 RF out; so the TV - DVD recorder - etc... get each their own signal and I get a very clean signal everywhere;
one of the outlets is attached to my older sVHS recorder, which I use as TV tuner and via the sVHS connect to a analog/digital converter and via firewire to my computer; I use that for recording certain programs and eliminate commercials

[iantri]

If it affects VHS playback and it only affects it when the cable is plugged in, one could only reasonably assume it is a problem with the cable, no?

Sounds as if somehow the cable has been incorrectly connected to ground or there is some sort of electrical in it. This is extremely bad!

Does your cable come in near your electricity? Go and see if the installer hasn't gone and tied them together; it happens sometimes. It's bad, but they do it anyway. Also check if it is properly grounded out there (but only if you know what you are doing.. don't want you to go and kill yourself.. ).

Is it an amplified splitter? To expand on what pluche said, the amplified splitter could also be improperly grounded, which is where the problem could be introduced.