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Old August 8th 03, 03:46 PM
Yuri Blanarovich
 
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Hi,

I looked through Albert Shadowitz's "The Electromagnetic Field",
and found on page 554 support for my original statement that antennas
"match" to the impedance of free space (377 Ohms).

I didn't buy the book, but professor Shadowitz did write on this
page about how creating antennas to most efficiently transfer power to
free space is a similar problem to matching a circuits source to its
load. He goes on to make a short comparison between source/load
impedances to an antenna matching to the impedance of free-space.

Food for thought and no doubt, debate.


Slick



Yep,
I tried to question that few moons back, but was "convinced" here that it is
not important.
Generally antenna exhibits all kinds of impedances along its length. I was
reasoning that antenna having its lowest impedance higher or closer to 377 ohm
should have better efficiency in coupling to the space (air). So loops and
folded dipoles should be better in that respect. K8CFU et al, when doing
experiments with verticals and radials, found that folded monopole measured
higher signal levels (over simple monopole) than expected.
Any progress since then?

Yuri, K3BU