Any antenna will be either "inductive" or "capacitive", depending on its
length as relative to the frequency its designed for. If it is short for the
frequency, it is usually capacitive, and if it is long for the frequency, it
will exhibit inductive qualities. The combination of these inductive and
capacitive factors, added vectorially, results in the "Z", or impedance , of
the antenna. Impedance is actually sort of a lossless form of resistance.
More info on these factors can be found in the arrl antenna handbook,
available from the arrl headquarters in Newington, Connecticut.

"Z" was a factor in these discuassions and arguments I have been having with
people about how their antenna's active element was "grounded' over the
years. for DC purposes, it may be grounded, but they fail to take into
account that the antenna's impedance to ground is actually higher than that
when RF energy is applied to it... The antenna is usually "grounded", so to
speak, through a reactive element that produces quite a high impedance
between ground and the active antenna element at RF. If it didn't , the
antenna would send and receive nothing, since all signals WOULD get shorted
to ground ! But, it seems the gist of this argument, which any novice ham
operator is more than familiar with, escapes them....

wrote in message
oups.com...
I know in a ground plane the angle of the radials can, but what about a
simple, multiple element yagi?
How does one measure what the impedance is or will be?