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Ground wire
The feed line is the cable or other transmission line that connects the antenna with the radio transmitter or receiver
In the transmission cooler line. Two wire connector
not unless the wire is exceptionally small, if if is 12 AWG or even 14 AWG you will be ok unless you are using it for a transmission line (unlikely)
The smallest wire you can use safely is a 21 AWG wire but that's not a wire used in the walls
Copper or aluminum wires.