Circular polarization - Texas Eggbeater
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| Oct 18th 2020, 16:39 | |
K9YOTotal 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 | |
W1VTSuper Moderator 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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