On 24/11/2019 18:11, Bill Wright wrote:
I'd like to do it that way but it would be hard (for me) to make
something that would do it, and would withstand all weathers.

Several years ago I added some contact strips for the sliding gate at
work. I ran the wires to them via a carbon fibre fishing rod sitting
half way back from the gate. It lasted for a few years until a more
modern, safer, gate was installed. The whip in the rod meant the loop
of wire did not sag much as the gate opened.