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Hf Antenna Question
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October 24th 06, 12:56 AM posted to rec.radio.amateur.antenna,alt.ham-radio.hf
Cecil Moore
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First recorded activity by RadioBanter: Jul 2006
Posts: 1,614
Hf Antenna Question
wrote:
I've never actually really compared bunching to helical wound.
The one they specify to build for my triband yagi is a helical
coil. On that antenna, I've used both methods, but not at the
same time to really compare. I didn't notice any real noticable
difference in operation though.
You wouldn't notice much difference for a single band
and maybe not even for a tribander. The helical has a
greater bandwidth than the bunched. For instance, at:
http://www.k1ttt.net/technote/airbalun.html
there's an 8 turn helical Vs 8 turn bunched. If the
target choking impedance is 500 ohms minimum, the helical
covers 6-24 MHz, a 4:1 ratio, while the bunched covers
4-10 MHz, a 2.5:1 ratio. The helical also has about two
times the maximum choking impedance as the bunched one.
--
73, Cecil
http://www.w5dxp.com
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