On 16 Oct 2003 09:59:07 -0700, (Tom Bruhns) wrote:

Roy Lewallen wrote in message ...
It's not clear to me what's meant by the voltage (presumably relative to
ground) at the tip of a dipole. Suppose it's a quarter wavelength above
ground. How would you measure it? Or, how would you measure the voltage
at the top of a quarter wavelength vertical?

Roy Lewallen, W7EL

Indeed... Or putting it another way, the potential between two points
does not have a unique value in the presence of a time-varying
magnetic field, which certainly is the case for a radiating dipole.
If you measure the voltage drop along the wire, it's essentially zero,
so along the wire the voltage between the end points of the dipole is
essentially the same as the voltage across the feedpoint. The only
difference between the ends and the feedpoint is due to I*R drop in
the wire. The voltage at the top of Roy's vertical, made out of

Ahhh...with the impedance variation I beg to differ.
Otherwise how could I draw a 3 or 4 inch arc off the end of a 160
meter dipole.

The end of the antenna is high impedance while the center (in the case
of a half wave dipole) is low. Low voltage and high current at the
center with high voltage and low current at the ends.

Roger Halstead (K8RI EN73 & ARRL Life Member)
www.rogerhalstead.com
N833R World's oldest Debonair? (S# CD-2)