Newsgroups: alt.home-theater.misc,comp.dcom.cabling,rec.video,rec.audio.tech
Subject: Re: RCA cables, wire types to use
References:  <[email protected]>
[email protected] (Stewart Pinkerton) writes:

> On 24 Apr 2002 10:05:27 -0700, [email protected] (Mouse Anony)
> wrote:
> 
> >Hi,
> >
> >I'm planning to connect my computer which has a Radeon 8500 (with TV
> >out) to my VCR in another room. The total length will be about 15m
> >(50ft for you Americans). I understand that this is quite long and may
> >not work but I still intend to try. I will be connecting to the
> >composite video RCA connector.
> >
> >I've been doing some research and I believe that I should get 75ohm
> >coaxial wire for the video. I will probably use either some old 75ohm
> >BNC network wire or some 75ohm RF wire. Is there any reason why I
> >should not use either of these? Is there really any special wire for
> >composite video?
> 
> Any well-made 75-ohm cable will be fine. Avoid cheap TV aerial cable,
> use proper pro-grade video cable, which has much heavier shielding.

You are fight on this.
 
> >As for the audio, well I'm still a bit confused about this. I believe
> >it isn't so critical. But what is the best kind of wire? Note that
> >this will be coming from the line out (i.e. unamplified) of my onboard
> >sound (ALC210 chip) or maybe my Audigy to the VCR. I think that I need
> >some kind of coaxial wire but what kind? Someone said TP but this just
> >sounds wrong...
> 
> Twisted pair is very good for reducing pickup of mains hum, 

Yes, if used together with balanced audio signals / interfaces.

With unbalanced interconnection twisted pair does not perform
that well as in balanced system. Unshielded twisted pair gives
poor performance when directly connected to unbalanced system.
Shielded twisted pair work OK in both balanced and unbalanced
audio interconnections.

> which is
> the most likely problem on a long run in a domestic environment. 

You are right. Poor shielding on cable and near mains cable/transformr
is one reason to pick up hum. Other common reason is ground loop,
where the cable shield does not help much.
Information what really helps to solve ground loops can be found at
 http://www.epanorama.net/documents/groundloop/index.html)

> Good
> microphone cable (twisted pair with shield) is probably the best
> option - works pretty well over the same distance in studios!

It is an excellent cable cable for sudio system where
balanced interconnection is the norm. And it works well
also with unbalanced signal source (although nowhere near
how well it woudl work on balanced environment).

-- 
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at 
http://www.epanorama.net/