Before revision: To get 600 Ω parallel line, the same wires would be spaced ; 600 Ω is roughly the practical limit for transmission lines made wires wires rather than thicker tubing or copper clad steel cable .
After revision: To get 600 Ω parallel line, the same wires would be spaced ; 600 Ω is roughly the practical limit for transmission lines made with wire rather than thicker , or with aluminum or copper pipe copper clad steel cable .