"David" wrote
Does anyone know where I can find Er tables for various type and
diameter
of metal tubing so I can calculate Velocity coefficient Vp ?

=====================================
The velocity factor of any conductor, including tubes, depends only on
what surrounds it.

If the surroundings are air, which is mainly oxygen and nitrogen, then
the VF = 1.00, equivalent, in metric units, to a velocity of 300
metres per micro-second. Or in ancient, old-fashioned units, it is the
far-less-convenient 669600000 miles per hour, give or take a few
100,000 miles. Who cares?
---
Reg.