Join Date: Apr 2001
Location: Belmont, CA, USA
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Of course it is bad having H and V twisted together....
Twisted pairs are meant for a balanced signal, and if the signals
on the different wires aren't mirror images, you get lots of crosstalk. So H gets a small ghost of V, and V gets a small ghost of H.
But because H and V are only sync signals, this doesn't matter a whole lot unless you try to have a really really long run.
As long as the signal from the crosstalk doesn't exceed sync level,
it shouldn't be visible in any way.
As far as getting away with fewer conductors by sharing the return for R,G and B, this would be a bad idea, exactly for this reason of crosstalk.
For a very very short run, straight through cable (rather than twisted pairs) work for this approach (very cheap VGA cables work this way). But for long runs, you will get crosstalk.