Thread: Impedance of a wire over the earth
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Old September 19th 06, 02:44 AM posted to rec.radio.shortwave
Telamon Telamon is offline
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First recorded activity by RadioBanter: Jul 2006
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Default Impedance of a wire over the earth
In article .com,
wrote:

Given the on going OT flame feast I decided to enliven everyone's day
by posting something actually on topic.

Many, maybe most, or us have a random wire for an antenna.

Many may have wondered what the impedance of that wire might be.

http://www.microwaves101.com/encyclopedia/calwground.cfm

Enter 1 for the Permitivity. While insulation will have a very minor
effect, the air surrounding the antenna will swamp the insulations
contribution.

Wire size can be found at
http://www.tfcbooks.com/referenc/wiresize.htm.

Because most real world wires sag, I pick the highest point and
lowest point and average them.

Tests with a receiver and a RF noise bridge shows measured values
very close to the calculated values.

Impedance of a wire over ground.

Z= 138 * log (4* height / wire diameter)

--
Telamon
Ventura, California
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