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Old February 17th 10, 09:40 PM posted to rec.radio.amateur.antenna
Owen Duffy Owen Duffy is offline
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First recorded activity by RadioBanter: Dec 2006
Posts: 1,169
Default Zepp antenna the ultimate OCF?

K7ITM wrote in news:1a1dd526-f947-482c-84d9-dd789a6b8f75
@e19g2000prn.googlegroups.com:
....
I don't think it guarantees it.


That is the issue with the Zepp. Radiation is the result of current flowing
in the 'flat top' and the common mode component of current flowing in the
not-standardised feed line.

If the feedline was say a quarter wave vertical section (as is often
depicted) with the common mode point at the bottom effectively grounded
(not usually clearly described), you have a three quarter wave L fed one
quarter wave from the end. If the common mode point referred to above was
effectively isolated from ground, you have a different antenna, different
boundary conditions to satisfy. Still, the are all Zepps to us!

Owen