There is one important fact Iâ€™d like to stress:
ALL WIRE IS NOT CREATED EQUAL!!!
Truthfully, there are physical characteristics of the wire itself that tend to limit the quality of video signal you can get from it.
One thing that seems to attract interference with a composite video coax is â€“if the cable has a bare copper wire mesh shield for the ground wire. Better cable has a tinned copper mesh. Another thing is the amount and type of insulation used on the center conductor and whether that conductor is solid or stranded.
One thing Iâ€™ve also noticed with factory preassembled composite video cables is that not all the wire strands of the ground mesh are soldered to the RCA connector. I guess the factory was either in a rush for mass assembly or they feel itâ€™s not necessary for all of the ground wire to be attached.
As I have mentioned before there are a lot of metal RCA connectors which do not have any silicone rubber to block interference between the positive center pole and the negative.
Also Iâ€™d like you to know that some low end composite video cables have a steel spring for strain relief â€“it looks like brass but its not and its magnetic and can be a cause of some interference problems (i.e.black curvy lines) even if it has silicone rubber covering everything inside the RCA connector.
So what do I recommend for everybody is monster cable M1000-series composite video cable. Then unscrew the connector and fill it with silicone rubber. Also there are noise clamps specifically designed to go on power cable, RF cable, and audio cables. They increase the resistance at the input jacks to block RFI interference.
Of course you could always make your own cables.