> the impedance is 36.0 ohms, independent of diameter for a range of
> diameters from 0.00001 to .02 wavelengths. This doesn't agree with
> any textbooks on the subject that I have read.
Don't most textbook methods of radiation resistance
calculation determine the total power radiated by an antenna, then
divide by the square of the base current, known from the assumed
current distribution, to get the radiation resistance? This would
seem to be independent of wire diameter since the power density (E x
H) caused by the current distribution gets integrated over a large
sphere enclosing the antenna. Reactance, on the other hand, depends
on the ratio of the voltage at the base divided by the current, and
can have complex values, a "fat" conductor being harder to drive and
having a lower rate of change of voltage for the same current step,
hence larger capacitance.
73, Paul, AA1LL
Paul E. Gili
Sanders, A Lockheed-Martin Co.
Voice: 603-885-3938
Facsimile: 603-885-1005
Received on Tue Sep 21 1999 - 06:51:30 EDT
This archive was generated by hypermail 2.2.0 : Sat Oct 02 2010 - 00:10:39 EDT