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Old 06-30-2012, 09:32 AM   #1
Thadde
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Default Complexe resistanc of an endfed wire

Hallo everybody

I am interested to calculate the complexe resistance of an endfed wire antenna. The following is known:

-Length of the wire

-Diameter of the wire (mm)

-High above the ground

-Working frequency

Is there anybody who knows to calculate it with the necessary formulas?
Thanks in advance with mni 73 de Thadde HB9DNB Switzerland
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Old 06-30-2012, 10:32 AM   #2
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Welcome to Open Roads Radio.net.

Do you mean the impedance (Z) of the antenna?

There's some pretty smart folks on here, I bet someone will get you an answer. I have plans today but finding that answer in one of my books sounds like a project for tomorrow.

OK, all you engineers - what's the formula?
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Old 06-30-2012, 11:55 AM   #3
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You might take a look at,

http://www.cebik.com/content/index.htm
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Old 06-30-2012, 12:54 PM   #4
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OR down load this Article (pdf) .
http://www.kc7hxc.us/links/radio/hf/...ire-kc7hxc.pdf
OR
http://www.smeter.net/antennas/end-fed-matching.php
OR
http://www.laarrl.org/pdfs/upthecoax10.pdf
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Old 07-01-2012, 06:37 AM   #5
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Let me add two more sites to the list.

http://www.aa5tb.com/efha.html

AND

http://www.njqrp.org/n2cxantennas/halfer/index.html

As you most likely know, impedance whether simple or complex , is going to be relative to frequency, if you are concerned with a single band it should be fairly simple , but the more harmonically related bands you try for the more complex things become, an antenna analyzer IS the best tool to use here, a "GRID DIP METER" would be the next best .

Good Luck & 73, John
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Old 07-01-2012, 11:40 AM   #6
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Hey Thadde,

Give us the numbers to plug into the formula. That should be more fun!!
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Old 07-01-2012, 03:41 PM   #7
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If you buy the ARRL antenna book, the program you need is on a CD taped to the inside cover (Back I think).
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