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Old July 7th 06, 08:46 PM posted to rec.radio.amateur.homebrew
Joel Kolstad Joel Kolstad is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 102
Default What is a wire antenna's impedance?

wrote in message
ups.com...
I searched all over the Internet and many books but just could not find
a formula or rough number of a wire antenna's impedance (not dipole or
anything else, just a simple, plain wire).


Have you tried "Antennas for All Applications" by Kraus
(http://www.amazon.com/gp/product/007...1652?ie=UTF8)?
It has plenty of plots of input impedance for various antennas. Any
university library will have some edition of Kraus' book; it's been around for
decades.

I'm about 99% certain the ARRL handbook has plenty of antenna impledance plots
as well.

But I just don't know the wire's impedance's range,
say, is it in the 50-80 ohms or in the 500-600 ohms range or even
1000-2000 ohms?


For most antennas at least in the ballpark of resonance, you'll be in the
30-300 ohm range. Real antennas often have tens to hundreds of ohms of
reactance as well, though.

So take an
example, if I use a wire antenna, say, 22 AWG, spools of solid, and the
length=wavelength/4, what is its approximate impedance?


In the ballpark of 72 ohms assuming it's a dipole (lambda/4 on either side);
if you're operating lambda/4 above a ground plane, it'll be roughly half that.

---Joel Kolstad