yes, a wire in free space has a velocity factor... if the formula for
the antenna in question does not all ready take that velocity factor
into consideration, you will need to consider the velocity...

.... there is also "end effect"...

.... simplest thing to do would be to use the formula which takes this
all into consideration...

.... first, I would google for "shortened antennas" or "shortened
radiators" and get a bit more familiar with "loading" the antenna to
resonance...

Warmest regards,
John
"redhat" wrote in message
ps.com...
what about the velocity factor of the wire, should i use it in the
equation of the antenna length or not?