The question has arisen before of how Star Quad cabling works and why do we need it.

I just found this very interesting link

http://www.canare.com/starquad.html

What is the longest run of cable you can effectively use? 100'? 200'? more???

Yes, starquad is supposed to be good at RF rejection. I have heard a few
things about it not being the best cable when you are *not* needing RF
shielding. However, those cases are most likely 'golden ears'
(with sh*t between) listening on systems WAY better than anyone on
this board could afford.

I like the suppleness of the cable, but the extra wires are a bit annoying
to deal with when soldering TRS connectors.

For cable that is bomb proof and a solid contender, Belden 8412 gets my
vote, but not that easy to deal with either.
For real thin stuff that has great specs, Mogami.

You are supposed to be able to run up to 600' balanced, but much over
200' you are going to lose signal. My rule, keep your cable run as short
as possible always.

Jay Rose's books have some information on starquad cable. Symnopsis: It does give extra intereference rejection for mic-level signals. Don't bother with line-level signals.

Glenn
It will give better rejection on line level as well, Line level is less likely to experience interference is all. On a long run any help would be good I imagine.