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Old July 16th 03, 07:17 PM
Dilon Earl
Posts: n/a

On Tue, 15 Jul 2003 01:20:02 -0700, Roy Lewallen

No, an antenna doesn't "match" the impedance of free space. The input
impedance of an antenna is the ratio of V to I. The impedance of free
space is the ratio of the E field to the H field of a plane wave. They
both happen to have units of ohms, but they're different things and
there's no "matching" going on. If you apply 100 watts to an antenna,
resonant or not, 100 watts will be radiated, less loss, regardless of
the antenna's input impedance.
Roy Lewallen, W7EL

Hope you don't mind if I ask you a couple of questions about your
last sentence.
Given a 75 ohm dipole fed 100 watts with 75 0hm coax. Assume no
losses, now if the antenna's input impedance is changed to say 50 ohms
(non-reactive). You would have some loss with the mismatch between
the coax and antenna?
The transmitter would see 50 ohms?