Addressed to nobody in particular.

From basic transmission line theory, the velocity of propagation along
a coil is estimated by -

V = 1 / Sqrt( L * C ) metres per second,

where L and C are henrys and farads per metre respectively. The
formula for L and C can be found in your Bibles from coil dimensions,
numbers of turns, etc.

The velocity factor = V / c and Zo = Sqr( L / C ).

Attenuation (loss) = R / 2 / Zo nepers, where R is wire resistance
plus radiation resistance.

From which other interesting facts can be deduced.
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Reg.