[Antennas] Velocity factor for wire?

[Merv Stump]

Chris, I doubt that you will find a velocity factor for wire which is
general enough and accurate enough to be of much help.  However, keep in
mind the following:

1.  The formula for calculating a half-wave length is 492/fMHz.  However
the formula we use for calculating the length of a half-wave antenna is
468/fMHz.  468/492 is .95.  Some of this differential is due to "end
effect" but most is due to the velocity factor.  So one might say (with
some reservations) that the velocity factor of wire is .95.

Now comes the "howevers"

2.  The formula for calculating the length of a full-wave length is
984/fMHz, however as Orr and many others have documented full-wave loops
are electrically short so the formula we use for calculating the length
of a full-wave loop antenna is 1005/fMHz.

3.  One more "however" - insulated wire is electrically long by from 1
to 3 percent.  Bottom line - when using insulated wire for an antenna I
use the appropriate formula and then reduce the length by 2%. 

All of which is why God made wire cutters and soldering irons, as well
as modeling programs. 

Merv, W2OE