Hello.

Random wire to me means try and tune This. ;)
With that said, I have placed trailer landing gear on boards that sit on old tires and tuned one as the radiator and the other as a counterpoise.
Do I say random trailer antenna?
The point being random may mean that although the size may be known it is in fact a random object.
In San Antonio there was this Gamewell fire telegraph system.
Although the stations are all gone some of the overhead wiring is still around.
I have spliced into the type BB telegraph wire and use that for my 160 meter antenna.
This might be considered random wire as it is about as random as one can get.
I made sure that it was not connected to anything beforehand and was in good repair.