On 5 Mar, 08:04, "Wayne" wrote:
When the subject of antenna efficiency comes up, it often involves a
discussion of ground losses on verticals. What about, for example, a
dipole? Could one calculate "power out/power in" by measuring the VSWR and
declaring that everything not reflected was transmitted? It would seem more
accurate to actually measure power out and power in, but that introduces
inaccuracies by having to calibrate the setup. Thoughts?

In my opinion NO!

You have two resistances, one for Radiation
and one for wire resistance ie skin resistance
However, you can measure the resistance as a loss and then utelise
your equation for a dipole that is resonant.
If more than one element is being measured then each element must be
resonant in situ before you can repeat that particular
method.
My thought behind this is and I can be in error, that some "radiation"
in its formative
period may well cancel each other in the near field.
Art