Well their original cable was rg59 and was corroded, split open, pretty much beat to the end of its life so since I was running very long spans I decided to go with RG6quad shield since it was a high interference environment. I did not know that it is not good at low frequencies. The longest span is still good but the rest of the cameras are shot, they were dead before I changed the wiring. What would be your suggestion for very long runs, say 100 meters and in very close proximity to fluorescent fixtures?