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Thadde
06-30-2012, 10:32 AM
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

Radio
06-30-2012, 11:32 AM
:welcome:

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?

W9WLS
06-30-2012, 12:55 PM
You might take a look at,

http://www.cebik.com/content/index.htm

W9WLS
06-30-2012, 01:54 PM
OR down load this Article (pdf) .
http://www.kc7hxc.us/links/radio/hf/Long-Wire%20Notes/longwire-kc7hxc.pdf
OR
http://www.smeter.net/antennas/end-fed-matching.php
OR
http://www.laarrl.org/pdfs/upthecoax10.pdf

W9WLS
07-01-2012, 07:37 AM
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

Radio
07-01-2012, 12:40 PM
Hey Thadde,

Give us the numbers to plug into the formula. That should be more fun!! :think:

wa8yxm
07-01-2012, 04:41 PM
If you buy the ARRL antenna book, the program you need is on a CD taped to the inside cover (Back I think).