On Wednesday, May 7, 2014 9:18:34 PM UTC-4, Foxs Mercantile wrote:
On 5/7/2014 11:26 AM, KB6NU via rec.radio.info Admin wrote:

This is not to say that velocity factor isnt a real phenomenon,
just that it isnt a factor when cutting a length of wire for use
in a dipole.

Well, actually it is. You'll find that a piece of bare wire will
be somehwat longer than a piece of insulated wire. For example,
using THHN electrical house wire for an antenna.

I have to agree with Jeff.

What happens is that there are quite a few factors into what makes the correct length for a wire antenna. Height above ground, loads of course, capacity hats, ground type, wire size. And the insulation on the wire has an effect.

If you look at an antenna design program, say EZ-Nec, you'll see that both the insulation thickness and the dieletric have an effect upon how fast the RF travels through the wire. Capacitive effects? Yup.

http://en.wikipedia.org/wiki/Velocity_factor

Explains VF

Some antennas have been constructed that use the VF to a relative extreme. It's no free lunch, but can make for interesting antennas.