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Circular polarization - Texas Eggbeater

Oct 18th 2020, 16:39

K9YO

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
I am building a Texas eggbeater http://wb5rmg.somenet.net/k5oe/Eggbeater_2.html
using the matching network given in http://www.arrl.org/files/file/ETP/ISS20Antenna/ISS20Antenna%20article.pdf because you can no longer find the coax mentioned in the first reference.

I have everything bent and connected. I used my new nano vna and did an analysis. This is what I got? I am not quite sure how to read it. Is the antenna OK?

Ugh! you cannot paste a picture. Thanks for reading this.

Ken
Oct 19th 2020, 06:41

W1VT

Super Moderator

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
The difference is that the ISS uses simple dipole elements above a ground plane for a 50 ohm impedance, while an eggbeater uses loop antennas that typically have an impedance of 100 to 140 ohms which is much higher than that.

ebay may be a source of surplus RG-62 93 ohm coax.

https://on6wg.pagesperso-orange.fr/Doc/Eggbeater-Ant-Revisited-English.pdf
This article describes how to make parallel 100 ohm line out of 50 ohm coax and feed an eggbeater.

Zak Lau W1VT
ARRL Senior Lab Engineer

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