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

Cecil Moore wrote:
Jeffdeham wrote:

Cecil Moore wrote:

V^2/600=100w


Where did the value of V and 600 come from in this formula?


V is the unknown. 600 ohms is the approximate ball park feedpoint
impedance for a traveling-wave antenna.

I'd like to be able to calculate the voltages also for let's say my 5
watt QRP rig.


Remember, it is a really rough estimate. For 5w, V^2/600=5w, so
V ~ 55v RMS. The peak voltage at the end of a dipole fed with 5w
would be very roughly 150 volts.