Hi,
I cannot come up with an answer.

Let's say I have a coax cable with 83% velocity factor. I want to use
its inner conductor (that is solid copper single conductor) so I remove
the outer sheath and the braid.

I am left with the inner conductor and what was the dielectric, now
performing as an insulator around my wire.

What is the resulting velocity factor?
* 83%, as the original cable
* 100%, copper's
* something else?

I have experienced that wire dipoles and verticals built with insulated
electric wire have a final length shorter than the theoretical value. I
"suspected" the PVC coating to vary the velocity factor. Am I wrong?

Thank you in advance for your hints.
Paolo IK1ZYW