There used to be a device used to transform ordinary wire into very high power transmission line. It launched the wave along the surface of the wire, following the path of the wire, but not actually transmitting power through the wire. Was used for feeding TV station antennas. Unfortunately it is probably not possible to do this at HF frequencies!
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That would be Goubau line - Wikipedia
Back on-topic: I use a single wire from a large spool of computer ribbon cable. It is very light, flexible, can be stripped with your fingernails and usually lasts a few activations. It does stretch a bit and ultimately breaks, but it works for me.
73,
Wouter Jan PE4WJ