What to look for in a coax cable?

[irishScott]

I need a 20-30' coax cable for my dorm. I've got a few lying around, but when I hook them up the picture always has some sort of minor distortion. Watchable, but definitely not full quality. I tried a friend's cable and the picture came in perfect, so it's definitely the cable. Any recommendations/suggestions? Does copper vs Aluminum make a difference?

 

[mshan]

http://www.bluejeanscable.com/store/rf/index.htm

 

[The Boston Dangler]

you want RG-6 cable, quad-shielded, with threaded F connectors. gold connectors on this are just silly.