impedance of a wire antenna, knowing it's length and height above ground?

Brian

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Anyone here know of a formula or other manner in which to determine the

impedance of a wire antenna, knowing it's length and height above ground?

impedance of a wire antenna, knowing it's length and height above ground?

Brian

Sorry, can't spell today. Should've been discerning I believe.

Quote:> Anyone here know of a formula or other manner in which to determine the

> impedance of a wire antenna, knowing it's length and height above ground?

> Brian

> Anyone here know of a formula or other manner in which to determine the

> impedance of a wire antenna, knowing it's length and height above ground?

Z is in ohms

H is the height of the wire above ground in feet.

D is the diameter of the wire in inches

The length of the wire does not matter.

This is Z is the result of electric field effects measured relative from

earth ground.

You can see by formula that the higher the wire is the higher the

impedance and the larger the wire size the lower the impedance will be

for the wire.

A typical wire will represent hundreds of ohms. An 18 guage wire would

be ~ 500 to ~ 600 ohms 5 to 15 feet above ground.

--

Telamon

Ventura, California

A good source for these formulas is the ARRL antenna book. The ARRLQuote:> Anyone here know of a formula or other manner in which to determine

the

> impedance of a wire antenna, knowing it's length and height above

ground?

> Brian

radio amateur's handbook also has some antenna formulas, and is often

found in public libraries.

Here's a couple of radio amateur sites:

http://www.cebik.com/radio.html

Look for the "Practical Antenna Notes"

Reg Edwards has written some computer programs which greatly simplify

using some of the more complicated formulas. There are a few of them

for antennas:

http://www.btinternet.com/~g4fgq.regp/page3.html#S301"

But the effects of the antenna's impedance are far more important when

transmitting. As a practical matter, receivers work fine over a broad

range of impedances.

Frank Dresser

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